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# Customising Roundup

Contents

- Customising Roundup

## What You Can Do

Before you get too far, it's probably worth having a quick read of the Roundup design documentation.

Customisation of Roundup can take one of six forms:

1. tracker configuration changes
2. database, or tracker schema changes
3. "definition" class database content changes
4. behavioural changes, through detectors
5. security / access controls
6. change the web interface

The third case is special because it takes two distinctly different forms depending upon whether the tracker has been initialised or not. The other two may be done at any time, before or after tracker initialisation. Yes, this includes adding or removing properties from classes.

## Trackers in a Nutshell

Trackers have the following structure:

Tracker File | Description
--- | ---
config.ini | Holds the basic tracker configuration
schema.py | Holds the tracker schema
initial_data.py | Holds any data to be entered into the database when the tracker is initialised.
db/ | Holds the tracker's database
db/files/ | Holds the tracker's upload files and messages
db/backend_name | Names the database back-end for the tracker
detectors/ | Auditors and reactors for this tracker
extensions/ | Additional web actions and templating utilities.
html/ | Web interface templates, images and style sheets
lib/ | optional common imports for detectors and extensions

## Tracker Configuration

The `config.ini` located in your tracker home contains the basic configuration for the web and e-mail components of roundup's interfaces.

Changes to the data captured by your tracker is controlled by the tracker schema. Some configuration is also performed using permissions - see the security / access controls section. For example, to allow users to automatically register through the email interface, you must grant the "Anonymous" Role the "Email Access" Permission.

The following is taken from the Python Library Reference (May 20, 2004) section "ConfigParser -- Configuration file parser":

> The configuration file consists of sections, led by a "[section]" header and followed by "name = value" entries, with line continuations on a newline with leading whitespace. Note that leading whitespace is removed from values. The optional values can contain format strings which refer to other values in the same section. Lines beginning with "#" or ";" are ignored and may be used to provide comments.

> For example:

>     [My Section]
>     foodir = %(dir)s/whatever
>     dir = frob

> would resolve the "%(dir)s" to the value of "dir" ("frob" in this case) resulting in "foodir" being "frob/whatever".

Section main
  database -- `db`
    Database directory path. The path may be either absolute or relative to the directory containig this config file.
  templates -- `html`
    Path to the HTML templates directory. The path may be either absolute or relative to the directory containig this config file.
  static_files -- default blank
    Path to directory holding additional static files available via Web UI. This directory may contain sitewide images, CSS stylesheets etc. and is searched for these files prior to the TEMPLATES directory specified above. If this option is not set, all static files are taken from the TEMPLATES directory The path may be either absolute or relative to the directory containig this config file.
  admin_email -- `roundup-admin`
    Email address that roundup will complain to if it runs into trouble. If the email address doesn't contain an `@` part, the MAIL_DOMAIN defined below is used.
  dispatcher_email -- `roundup-admin`
    The 'dispatcher' is a role that can get notified of new items to the database. It is used by the ERROR_MESSAGES_TO config setting. If the email address doesn't contain an `@` part, the MAIL_DOMAIN defined below is used.
  email_from_tag -- default blank
    Additional text to include in the "name" part of the From: address used in nosy messages. If the sending user is "Foo Bar", the From: line is usually: `"Foo Bar" <issue_tracker@tracker.example>` the EMAIL_FROM_TAG goes inside the "Foo Bar" quotes like so: `"Foo Bar EMAIL_FROM_TAG" <issue_tracker@tracker.example>`
  new_web_user_roles -- `User`
    Roles that a user gets when they register with Web User Interface. This is a comma-separated list of role names (e.g. `Admin,User`).
  new_email_user_roles -- `User`
    Roles that a user gets when they register with Email Gateway. This is a comma-separated string of role names (e.g. `Admin,User`).
  error_messages_to -- `user`
    Send error message emails to the `dispatcher`, `user`, or `both`? The dispatcher is configured using the DISPATCHER_EMAIL setting. Allowed values: `dispatcher`, `user`, or `both`
  html_version -- `html4`
    HTML version to generate. The templates are `html4` by default. If you wish to make them xhtml, then you'll need to change this var to `xhtml` too so all auto-generated HTML is compliant. Allowed values: `html4`, `xhtml`
  timezone -- `0`
    Numeric timezone offset used when users do not choose their own in their settings.
  instant_registration -- `yes`
    Register new users instantly, or require confirmation via email? Allowed values: `yes`, `no`
  email_registration_confirmation -- `yes`
    Offer registration confirmation by email or only through the web? Allowed values: `yes`, `no`
  indexer_stopwords -- default blank
    Additional stop-words for the full-text indexer specific to your tracker. See the indexer source for the default list of stop-words (e.g. `A,AND,ARE,AS,AT,BE,BUT,BY, ...`).
  umask -- `02`
    Defines the file creation mode mask.
Section tracker
  name -- `Roundup issue tracker`
    A descriptive name for your roundup instance.
  web -- `http://host.example/demo/`
    The web address that the tracker is viewable at. This will be included in information sent to users of the tracker. The URL MUST include the cgi-bin part or anything else that is required to get to the home page of the tracker. You MUST include a trailing '/' in the URL.
  email -- `issue_tracker`
    Email address that mail to roundup should go to.
  language -- default blank
    Default locale name for this tracker. If this option is not set, the language is determined by the environment variable LANGUAGE, LC_ALL, LC_MESSAGES, or LANG, in that order of preference.
Section web
  allow_html_file -- `no`
    Setting this option enables Roundup to serve uploaded HTML file content as HTML. This is a potential security risk and is therefore disabled by default. Set to 'yes' if you trust all users uploading content to your tracker.
  http_auth -- `yes`
    Whether to use HTTP Basic Authentication, if present. Roundup will use either the REMOTE_USER or HTTP_AUTHORIZATION variables supplied by your web server (in that order). Set this option to 'no' if you do not wish to use HTTP Basic Authentication in your web interface.
  use_browser_language -- `yes`
    Whether to use HTTP Accept-Language, if present. Browsers send a language-region preference list. It's usually set in the client's browser or in their Operating System. Set this option to 'no' if you want to ignore it.
  debug -- `no`
    Setting this option makes Roundup display error tracebacks in the user's browser rather than emailing them to the tracker admin."),
Section rdbms

  Settings in this section are used by Postgresql and MySQL backends only

  name -- `roundup`
    Name of the database to use.
  host -- `localhost`
    Database server host.
  port -- default blank
    TCP port number of the database server. Postgresql usually resides on port 5432 (if any), for MySQL default port number is 3306. Leave this option empty to use backend default.
  user -- `roundup`
    Database user name that Roundup should use.
  password -- `roundup`
    Database user password.
  read_default_file -- `~/.my.cnf`
    Name of the MySQL defaults file. Only used in MySQL connections.
  read_default_group -- `roundup`
    Name of the group to use in the MySQL defaults file. Only used in MySQL connections.
Section logging
  config -- default blank
    Path to configuration file for standard Python logging module. If this option is set, logging configuration is loaded from specified file; options 'filename' and 'level' in this section are ignored. The path may be either absolute or relative to the directory containig this config file.
  filename -- default blank
    Log file name for minimal logging facility built into Roundup. If no file name specified, log messages are written on stderr. If above 'config' option is set, this option has no effect. The path may be either absolute or relative to the directory containig this config file.
  level -- `ERROR`
    Minimal severity level of messages written to log file. If above 'config' option is set, this option has no effect. Allowed values: `DEBUG`, `INFO`, `WARNING`, `ERROR`
Section mail

  Outgoing email options. Used for nosy messages, password reset and registration approval requests.

  domain -- `localhost`
    Domain name used for email addresses.
  host -- default blank
    SMTP mail host that roundup will use to send mail
  username -- default blank
    SMTP login name. Set this if your mail host requires authenticated access. If username is not empty, password (below) MUST be set!
  password -- default blank
    SMTP login password. Set this if your mail host requires authenticated access.
  port -- default 25
    SMTP port on mail host. Set this if your mail host runs on a different port.
  local_hostname -- default blank
    The fully qualified domain name (FQDN) to use during SMTP sessions. If left blank, the underlying SMTP library will attempt to detect your FQDN. If your mail host requires something specific, specify the FQDN to use.
  tls -- `no`
    If your SMTP mail host provides or requires TLS (Transport Layer Security) then you may set this option to 'yes'. Allowed values: `yes`, `no`
  tls_keyfile -- default blank
    If TLS is used, you may set this option to the name of a PEM formatted file that contains your private key. The path may be either absolute or relative to the directory containig this config file.
  tls_certfile -- default blank
    If TLS is used, you may set this option to the name of a PEM formatted certificate chain file. The path may be either absolute or relative to the directory containig this config file.
  charset -- utf-8
    Character set to encode email headers with. We use utf-8 by default, as it's the most flexible. Some mail readers (eg. Eudora) can't cope with that, so you might need to specify a more limited character set (eg. iso-8859-1).
  debug -- default blank
    Setting this option makes Roundup to write all outgoing email messages to this file instead of sending them. This option has the same effect as environment variable SENDMAILDEBUG. Environment variable takes precedence. The path may be either absolute or relative to the directory containig this config file.
  add_authorinfo -- `yes`
    Add a line with author information at top of all messages send by roundup.
  add_authoremail -- `yes`
    Add the mail address of the author to the author information at the top of all messages. If this is false but add_authorinfo is true, only the name of the actor is added which protects the mail address of the actor from being exposed at mail archives, etc.
Section mailgw

  Roundup Mail Gateway options

  keep_quoted_text -- `yes`
    Keep email citations when accepting messages. Setting this to `no` strips out "quoted" text from the message. Signatures are also stripped. Allowed values: `yes`, `no`
  leave_body_unchanged -- `no`
    Preserve the email body as is - that is, keep the citations and signatures. Allowed values: `yes`, `no`
  default_class -- `issue`
    Default class to use in the mailgw if one isn't supplied in email subjects. To disable, leave the value blank.
  language -- default blank
    Default locale name for the tracker mail gateway. If this option is not set, mail gateway will use the language of the tracker instance.
  subject_prefix_parsing -- `strict`
    Controls the parsing of the [prefix] on subject lines in incoming emails. `strict` will return an error to the sender if the [prefix] is not recognised. `loose` will attempt to parse the [prefix] but just pass it through as part of the issue title if not recognised. `none` will always pass any [prefix] through as part of the issue title.
  subject_suffix_parsing -- `strict`
    Controls the parsing of the [suffix] on subject lines in incoming emails. `strict` will return an error to the sender if the [suffix] is not recognised. `loose` will attempt to parse the [suffix] but just pass it through as part of the issue title if not recognised. `none` will always pass any [suffix] through as part of the issue title.
  subject_suffix_delimiters -- `[]`
    Defines the brackets used for delimiting the commands suffix in a subject line.
  subject_content_match -- `always`
    Controls matching of the incoming email subject line against issue titles in the case where there is no designator [prefix]. `never` turns off matching. `creation + interval` or `activity + interval` will match an issue for the interval after the issue's creation or last activity. The interval is a standard Roundup interval.
  refwd_re -- `(\s*\W?\s*(fw|fwd|re|aw|sv|ang)\W)+`
    Regular expression matching a single reply or forward prefix prepended by the mailer. This is explicitly stripped from the subject during parsing. Value is Python Regular Expression (UTF8-encoded).
  origmsg_re -- `` ^[>|s]*-----s?Original Messages?-----$``
    Regular expression matching start of an original message if quoted the in body. Value is Python Regular Expression (UTF8-encoded).
  sign_re -- `^[>|\s]*-- ?$`
    Regular expression matching the start of a signature in the message body. Value is Python Regular Expression (UTF8-encoded).
  eol_re -- `[\r\n]+`
    Regular expression matching end of line. Value is Python Regular Expression (UTF8-encoded).
  blankline_re -- `[\r\n]+\s*[\r\n]+`
    Regular expression matching a blank line. Value is Python Regular Expression (UTF8-encoded).
Section pgp

  OpenPGP mail processing options

  enable -- `no`
    Enable PGP processing. Requires pyme.
  roles -- default blank
    If specified, a comma-separated list of roles to perform PGP processing on. If not specified, it happens for all users.
  homedir -- default blank
    Location of PGP directory. Defaults to $HOME/.gnupg if not specified.
Section nosy

  Nosy messages sending

  messages_to_author -- `no`
    Send nosy messages to the author of the message. Allowed values: `yes`, `no`, `new`
  signature_position -- `bottom`
    Where to place the email signature. Allowed values: `top`, `bottom`, `none`
  add_author -- `new`
    Does the author of a message get placed on the nosy list automatically? If `new` is used, then the author will only be added when a message creates a new issue. If `yes`, then the author will be added on followups too. If `no`, they're never added to the nosy. Allowed values: `yes`, `no`, `new`
  add_recipients -- `new`
    Do the recipients (`To:`, `Cc:`) of a message get placed on the nosy list? If `new` is used, then the recipients will only be added when a message creates a new issue. If `yes`, then the recipients will be added on followups too. If `no`, they're never added to the nosy. Allowed values: `yes`, `no`, `new`
  email_sending -- `single`
    Controls the email sending from the nosy reactor. If `multiple` then a separate email is sent to each recipient. If `single` then a single email is sent with each recipient as a CC address.
  max_attachment_size -- `2147483647`
    Attachments larger than the given number of bytes won't be attached to nosy mails. They will be replaced by a link to the tracker's download page for the file.

You may generate a new default config file using the `roundup-admin genconfig` command.

Configuration variables may be referred to in lower or upper case. In code, variables not in the "main" section are referred to using their section and name, so "domain" in the section "mail" becomes MAIL_DOMAIN. The configuration variables available are:

### Extending the configuration file

You can't add new variables to the config.ini file in the tracker home but you can add two new config.ini files:

- a config.ini in the `extensions` directory will be loaded and attached to the config variable as "ext".
- a config.ini in the `detectors` directory will be loaded and attached to the config variable as "detectors".

For example, the following in `detectors/config.ini`:

    [main]
    qa_recipients = email@example.com

is accessible as:

    db.config.detectors['QA_RECIPIENTS']

Note that the name grouping applied to the main configuration file is applied to the extension config files, so if you instead have:

    [qa]
    recipients = email@example.com

then the above `db.config.detectors['QA_RECIPIENTS']` will still work.

## Tracker Schema

Note

if you modify the schema, you'll most likely need to edit the web interface HTML template files and detectors to reflect your changes.

A tracker schema defines what data is stored in the tracker's database. Schemas are defined using Python code in the `schema.py` module of your tracker.

### The `schema.py` module

The `schema.py` module contains two functions:

open
  This function defines what your tracker looks like on the inside, the schema of the tracker. It defines the Classes and properties on each class. It also defines the security for those Classes. The next few sections describe how schemas work and what you can do with them.
init
  This function is responsible for setting up the initial state of your tracker. It's called exactly once - but the `roundup-admin initialise` command. See the start of the section on database content for more info about how this works.

### The "classic" schema

The "classic" schema looks like this (see section setkey(property) below for the meaning of `'setkey'` -- you may also want to look into the sections setlabelprop(property) and setorderprop(property) for specifying (default) labelling and ordering of classes.):

    pri = Class(db, "priority", name=String(), order=String())
    pri.setkey("name")

    stat = Class(db, "status", name=String(), order=String())
    stat.setkey("name")

    keyword = Class(db, "keyword", name=String())
    keyword.setkey("name")

    user = Class(db, "user", username=String(), organisation=String(),
        password=String(), address=String(), realname=String(),
        phone=String(), alternate_addresses=String(),
        queries=Multilink('query'), roles=String(), timezone=String())
    user.setkey("username")

    msg = FileClass(db, "msg", author=Link("user"), summary=String(),
        date=Date(), recipients=Multilink("user"),
        files=Multilink("file"), messageid=String(), inreplyto=String())

    file = FileClass(db, "file", name=String())

    issue = IssueClass(db, "issue", keyword=Multilink("keyword"),
        status=Link("status"), assignedto=Link("user"),
        priority=Link("priority"))
    issue.setkey('title')

### What you can't do to the schema

You must never:

Remove the users class
  This class is the only required class in Roundup.
Remove the "username", "address", "password" or "realname" user properties
  Various parts of Roundup require these properties. Don't remove them.
Change the type of a property
  Property types must never be changed - the database simply doesn't take this kind of action into account. Note that you can't just remove a property and re-add it as a new type either. If you wanted to make the assignedto property a Multilink, you'd need to create a new property assignedto_list and remove the old assignedto property.

### What you can do to the schema

Your schema may be changed at any time before or after the tracker has been initialised (or used). You may:

Add new properties to classes, or add whole new classes
  This is painless and easy to do - there are generally no repurcussions from adding new information to a tracker's schema.
Remove properties
  Removing properties is a little more tricky - you need to make sure that the property is no longer used in the web interface or by the detectors.

### Classes and Properties - creating a new information store

In the tracker above, we've defined 7 classes of information:

> priority
>   Defines the possible levels of urgency for issues.
> status
>   Defines the possible states of processing the issue may be in.
> keyword
>   Initially empty, will hold keywords useful for searching issues.
> user
>   Initially holding the "admin" user, will eventually have an entry for all users using roundup.
> msg
>   Initially empty, will hold all e-mail messages sent to or generated by roundup.
> file
>   Initially empty, will hold all files attached to issues.
> issue
>   Initially empty, this is where the issue information is stored.

We define the "priority" and "status" classes to allow two things: reduction in the amount of information stored on the issue and more powerful, accurate searching of issues by priority and status. By only requiring a link on the issue (which is stored as a single number) we reduce the chance that someone mis-types a priority or status - or simply makes a new one up.

#### Class and Items

A Class defines a particular class (or type) of data that will be stored in the database. A class comprises one or more properties, which gives the information about the class items.

The actual data entered into the database, using `class.create()`, are called items. They have a special immutable property called `'id'`. We sometimes refer to this as the itemid.

#### Properties

A Class is comprised of one or more properties of the following types:

- String properties are for storing arbitrary-length strings.
- Password properties are for storing encoded arbitrary-length strings. The default encoding is defined on the `roundup.password.Password` class.
- Date properties store date-and-time stamps. Their values are Timestamp objects.
- Number properties store numeric values.
- Boolean properties store on/off, yes/no, true/false values.
- A Link property refers to a single other item selected from a specified class. The class is part of the property; the value is an integer, the id of the chosen item.
- A Multilink property refers to possibly many items in a specified class. The value is a list of integers.

All Classes automatically have a number of properties by default:

creator
  Link to the user that created the item.
creation
  Date the item was created.
actor
  Link to the user that last modified the item.
activity
  Date the item was last modified.

#### FileClass

FileClasses save their "content" attribute off in a separate file from the rest of the database. This reduces the number of large entries in the database, which generally makes databases more efficient, and also allows us to use command-line tools to operate on the files. They are stored in the files sub-directory of the `'db'` directory in your tracker. FileClasses also have a "type" attribute to store the MIME type of the file.

#### IssueClass

IssueClasses automatically include the "messages", "files", "nosy", and "superseder" properties.

The messages and files properties list the links to the messages and files related to the issue. The nosy property is a list of links to users who wish to be informed of changes to the issue - they get "CC'ed" e-mails when messages are sent to or generated by the issue. The nosy reactor (in the `'detectors'` directory) handles this action. The superseder link indicates an issue which has superseded this one.

They also have the dynamically generated "creation", "activity" and "creator" properties.

The value of the "creation" property is the date when an item was created, and the value of the "activity" property is the date when any property on the item was last edited (equivalently, these are the dates on the first and last records in the item's journal). The "creator" property holds a link to the user that created the issue.

#### setkey(property)

Select a String property of the class to be the key property. The key property must be unique, and allows references to the items in the class by the content of the key property. That is, we can refer to users by their username: for example, let's say that there's an issue in roundup, issue 23. There's also a user, richard, who happens to be user 2. To assign an issue to him, we could do either of:

    roundup-admin set issue23 assignedto=2

or:

    roundup-admin set issue23 assignedto=richard

Note, the same thing can be done in the web and e-mail interfaces.

#### setlabelprop(property)

Select a property of the class to be the label property. The label property is used whereever an item should be uniquely identified, e.g., when displaying a link to an item. If setlabelprop is not specified for a class, the following values are tried for the label:

> - the key of the class (see the setkey(property) section above)
> - the "name" property
> - the "title" property
> - the first property from the sorted property name list

So in most cases you can get away without specifying setlabelprop explicitly.

#### setorderprop(property)

Select a property of the class to be the order property. The order property is used whenever using a default sort order for the class, e.g., when grouping or sorting class A by a link to class B in the user interface, the order property of class B is used for sorting. If setorderprop is not specified for a class, the following values are tried for the order property:

> - the property named "order"
> - the label property (see setlabelprop(property) above)

So in most cases you can get away without specifying setorderprop explicitly.

#### create(information)

Create an item in the database. This is generally used to create items in the "definitional" classes like "priority" and "status".

#### A note about ordering

When we sort items in the hyperdb, we use one of a number of methods, depending on the properties being sorted on:

1. If it's a String, Number, Date or Interval property, we just sort the scalar value of the property. Strings are sorted case-sensitively.
2. If it's a Link property, we sort by either the linked item's "order" property (if it has one) or the linked item's "id".
3. Mulitlinks sort similar to #2, but we start with the first Multilink list item, and if they're the same, we sort by the second item, and so on.

Note that if an "order" property is defined on a Class that is used for sorting, all items of that Class must have a value against the "order" property, or sorting will result in random ordering.

### Examples of adding to your schema

The Roundup wiki has examples of how schemas can be customised to add new functionality.

## Detectors - adding behaviour to your tracker

Detectors are initialised every time you open your tracker database, so you're free to add and remove them any time, even after the database is initialised via the `roundup-admin initialise` command.

The detectors in your tracker fire before (auditors) and after (reactors) changes to the contents of your database. They are Python modules that sit in your tracker's `detectors` directory. You will have some installed by default - have a look. You can write new detectors or modify the existing ones. The existing detectors installed for you are:

nosyreaction.py
  This provides the automatic nosy list maintenance and email sending. The nosy reactor (`nosyreaction`) fires when new messages are added to issues. The nosy auditor (`updatenosy`) fires when issues are changed, and figures out what changes need to be made to the nosy list (such as adding new authors, etc.)
statusauditor.py
  This provides the `chatty` auditor which changes the issue status from `unread` or `closed` to `chatting` if new messages appear. It also provides the `presetunread` auditor which pre-sets the status to `unread` on new items if the status isn't explicitly defined.
messagesummary.py
  Generates the `summary` property for new messages based on the message content.
userauditor.py
  Verifies the content of some of the user fields (email addresses and roles lists).

If you don't want this default behaviour, you're completely free to change or remove these detectors.

See the detectors section in the design document for details of the interface for detectors.

### Detector API

Auditors are called with the arguments:

    audit(db, cl, itemid, newdata)

where `db` is the database, `cl` is an instance of Class or IssueClass within the database, and `newdata` is a dictionary mapping property names to values.

For a `create()` operation, the `itemid` argument is None and newdata contains all of the initial property values with which the item is about to be created.

For a `set()` operation, newdata contains only the names and values of properties that are about to be changed.

For a `retire()` or `restore()` operation, newdata is None.

Reactors are called with the arguments:

    react(db, cl, itemid, olddata)

where `db` is the database, `cl` is an instance of Class or IssueClass within the database, and `olddata` is a dictionary mapping property names to values.

For a `create()` operation, the `itemid` argument is the id of the newly-created item and `olddata` is None.

For a `set()` operation, `olddata` contains the names and previous values of properties that were changed.

For a `retire()` or `restore()` operation, `itemid` is the id of the retired or restored item and `olddata` is None.

### Additional Detectors Ready For Use

Sample additional detectors that have been found useful will appear in the `'detectors'` directory of the Roundup distribution. If you want to use one, copy it to the `'detectors'` of your tracker instance:

newissuecopy.py
  This detector sends an email to a team address whenever a new issue is created. The address is hard-coded into the detector, so edit it before you use it (look for the text 'team@team.host') or you'll get email errors!
creator_resolution.py
  Catch attempts to set the status to "resolved" - if the assignedto user isn't the creator, then set the status to "confirm-done". Note that "classic" Roundup doesn't have that status, so you'll have to add it. If you don't want to though, it'll just use "in-progress" instead.
email_auditor.py
  If a file added to an issue is of type message/rfc822, we tack on the extension .eml. The reason for this is that Microsoft Internet Explorer will not open things with a .eml attachment, as they deem it 'unsafe'. Worse yet, they'll just give you an incomprehensible error message. For more information, see the detector code - it has a length explanation.

### Auditor or Reactor?

Generally speaking, the following rules should be observed:

Auditors
  Are used for vetoing creation of or changes to items. They might also make automatic changes to item properties.
Reactors
  Detect changes in the database and react accordingly. They should avoid making changes to the database where possible, as this could create detector loops.

### Vetoing creation of or changes to items

Auditors may raise the `Reject` exception to prevent the creation of or changes to items in the database. The mail gateway, for example, will not attach files or messages to issues when the creation of those files or messages are prevented through the `Reject` exception. It'll also not create users if that creation is `Reject`'ed too.

To use, simply add at the top of your auditor:

    from roundup.exceptions import Reject

And then when your rejection criteria have been detected, simply:

    raise Reject

### Generating email from Roundup

The module `roundup.mailer` contains most of the nuts-n-bolts required to generate email messages from Roundup.

In addition, the `IssueClass` methods `nosymessage()` and `send_message()` are used to generate nosy messages, and may generate messages which only consist of a change note (ie. the message id parameter is not required - this is referred to as a "System Message" because it comes from "the system" and not a user).

## Database Content

Note

If you modify the content of definitional classes, you'll most likely need to edit the tracker detectors to reflect your changes.

Customisation of the special "definitional" classes (eg. status, priority, resolution, ...) may be done either before or after the tracker is initialised. The actual method of doing so is completely different in each case though, so be careful to use the right one.

Changing content before tracker initialisation
  Edit the initial_data.py module in your tracker to alter the items created using the `create( ... )` methods.
Changing content after tracker initialisation

  As the "admin" user, click on the "class list" link in the web interface to bring up a list of all database classes. Click on the name of the class you wish to change the content of.

  You may also use the `roundup-admin` interface's create, set and retire methods to add, alter or remove items from the classes in question.

See "adding a new field to the classic schema" for an example that requires database content changes.

## Security / Access Controls

A set of Permissions is built into the security module by default:

- Create (everything)
- Edit (everything)
- View (everything)

These are assigned to the "Admin" Role by default, and allow a user to do anything. Every Class you define in your tracker schema also gets an Create, Edit and View Permission of its own. The web and email interfaces also define:

Email Access
  If defined, the user may use the email interface. Used by default to deny Anonymous users access to the email interface. When granted to the Anonymous user, they will be automatically registered by the email interface (see also the `new_email_user_roles` configuration option).
Web Access
  If defined, the user may use the web interface. All users are able to see the login form, regardless of this setting (thus enabling logging in).
Web Roles
  Controls user access to editing the "roles" property of the "user" class. TODO: deprecate in favour of a property-based control.

These are hooked into the default Roles:

- Admin (Create, Edit, View and everything; Web Roles)
- User (Web Access; Email Access)
- Anonymous (Web Access)

And finally, the "admin" user gets the "Admin" Role, and the "anonymous" user gets "Anonymous" assigned when the tracker is installed.

For the "User" Role, the "classic" tracker defines:

- Create, Edit and View issue, file, msg, query, keyword
- View priority, status
- View user
- Edit their own user record

And the "Anonymous" Role is defined as:

- Web interface access
- Create user (for registration)
- View issue, file, msg, query, keyword, priority, status

Put together, these settings appear in the tracker's `schema.py` file:

    #
    # TRACKER SECURITY SETTINGS
    #
    # See the configuration and customisation document for information
    # about security setup.

    #
    # REGULAR USERS
    #
    # Give the regular users access to the web and email interface
    db.security.addPermissionToRole('User', 'Web Access')
    db.security.addPermissionToRole('User', 'Email Access')

    # Assign the access and edit Permissions for issue, file and message
    # to regular users now
    for cl in 'issue', 'file', 'msg', 'query', 'keyword':
        db.security.addPermissionToRole('User', 'View', cl)
        db.security.addPermissionToRole('User', 'Edit', cl)
        db.security.addPermissionToRole('User', 'Create', cl)
    for cl in 'priority', 'status':
        db.security.addPermissionToRole('User', 'View', cl)

    # May users view other user information? Comment these lines out
    # if you don't want them to
    db.security.addPermissionToRole('User', 'View', 'user')

    # Users should be able to edit their own details -- this permission
    # is limited to only the situation where the Viewed or Edited item
    # is their own.
    def own_record(db, userid, itemid):
        '''Determine whether the userid matches the item being accessed.'''
        return userid == itemid
    p = db.security.addPermission(name='View', klass='user', check=own_record,
        description="User is allowed to view their own user details")
    db.security.addPermissionToRole('User', p)
    p = db.security.addPermission(name='Edit', klass='user', check=own_record,
        description="User is allowed to edit their own user details")
    db.security.addPermissionToRole('User', p)

    #
    # ANONYMOUS USER PERMISSIONS
    #
    # Let anonymous users access the web interface. Note that almost all
    # trackers will need this Permission. The only situation where it's not
    # required is in a tracker that uses an HTTP Basic Authenticated front-end.
    db.security.addPermissionToRole('Anonymous', 'Web Access')

    # Let anonymous users access the email interface (note that this implies
    # that they will be registered automatically, hence they will need the
    # "Create" user Permission below)
    # This is disabled by default to stop spam from auto-registering users on
    # public trackers.
    #db.security.addPermissionToRole('Anonymous', 'Email Access')

    # Assign the appropriate permissions to the anonymous user's Anonymous
    # Role. Choices here are:
    # - Allow anonymous users to register
    db.security.addPermissionToRole('Anonymous', 'Create', 'user')

    # Allow anonymous users access to view issues (and the related, linked
    # information)
    for cl in 'issue', 'file', 'msg', 'keyword', 'priority', 'status':
        db.security.addPermissionToRole('Anonymous', 'View', cl)

    # [OPTIONAL]
    # Allow anonymous users access to create or edit "issue" items (and the
    # related file and message items)
    #for cl in 'issue', 'file', 'msg':
    #   db.security.addPermissionToRole('Anonymous', 'Create', cl)
    #   db.security.addPermissionToRole('Anonymous', 'Edit', cl)

### Automatic Permission Checks

Permissions are automatically checked when information is rendered through the web. This includes:

1. View checks for properties when being rendered via the `plain()` or similar methods. If the check fails, the text "[hidden]" will be displayed.
2. Edit checks for properties when the edit field is being rendered via the `field()` or similar methods. If the check fails, the property will be rendered via the `plain()` method (see point 1. for subsequent checking performed)
3. View checks are performed in index pages for each item being displayed such that if the user does not have permission, the row is not rendered.
4. View checks are performed at the top of item pages for the Item being displayed. If the user does not have permission, the text "You are not allowed to view this page." will be displayed.
5. View checks are performed at the top of index pages for the Class being displayed. If the user does not have permission, the text "You are not allowed to view this page." will be displayed.

### New User Roles

New users are assigned the Roles defined in the config file as:

- NEW_WEB_USER_ROLES
- NEW_EMAIL_USER_ROLES

The users may only edit their issues example shows customisation of these parameters.

### Changing Access Controls

You may alter the configuration variables to change the Role that new web or email users get, for example to not give them access to the web interface if they register through email.

You may use the `roundup-admin` "`security`" command to display the current Role and Permission configuration in your tracker.

#### Adding a new Permission

When adding a new Permission, you will need to:

1. add it to your tracker's `schema.py` so it is created, using `security.addPermission`, for example:

       self.security.addPermission(name="View", klass='frozzle',
           description="User is allowed to access frozzles")

   will set up a new "View" permission on the Class "frozzle".

2. enable it for the Roles that should have it (verify with "`roundup-admin security`")

3. add it to the relevant HTML interface templates

4. add it to the appropriate xxxPermission methods on in your tracker interfaces module

The `addPermission` method takes a couple of optional parameters:

properties
  A sequence of property names that are the only properties to apply the new Permission to (eg. `... klass='user', properties=('name', 'email') ...`)
check
  A function to be execute which returns boolean determining whether the Permission is allowed. The function has the signature `check(db, userid, itemid)` where `db` is a handle on the open database, `userid` is the user attempting access and `itemid` is the specific item being accessed.

#### Example Scenarios

See the examples section for longer examples of customisation.

anonymous access through the e-mail gateway
  Give the "anonymous" user the "Email Access", ("Edit", "issue") and ("Create", "msg") Permissions but do not not give them the ("Create", "user") Permission. This means that when an unknown user sends email into the tracker, they're automatically logged in as "anonymous". Since they don't have the ("Create", "user") Permission, they won't be automatically registered, but since "anonymous" has permission to use the gateway, they'll still be able to submit issues. Note that the Sender information - their email address - will not be available - they're anonymous.
automatic registration of users in the e-mail gateway
  By giving the "anonymous" user the ("Create", "user") Permission, any unidentified user will automatically be registered with the tracker (with no password, so they won't be able to log in through the web until an admin sets their password). By default new Roundup trackers don't allow this as it opens them up to spam. It may be enabled by uncommenting the appropriate addPermissionToRole in your tracker's `schema.py` file. The new user is given the Roles list defined in the "new_email_user_roles" config variable.
only developers may be assigned issues
  Create a new Permission called "Fixer" for the "issue" class. Create a new Role "Developer" which has that Permission, and assign that to the appropriate users. Filter the list of users available in the assignedto list to include only those users. Enforce the Permission with an auditor. See the example restricting the list of users that are assignable to a task.
only managers may sign off issues as complete

  Create a new Permission called "Closer" for the "issue" class. Create a new Role "Manager" which has that Permission, and assign that to the appropriate users. In your web interface, only display the "resolved" issue state option when the user has the "Closer" Permissions. Enforce the Permission with an auditor. This is very similar to the previous example, except that the web interface check would look like:

      <option tal:condition="python:request.user.hasPermission('Closer')"
              value="resolved">Resolved</option>

don't give web access to users who register through email
  Create a new Role called "Email User" which has all the Permissions of the normal "User" Role minus the "Web Access" Permission. This will allow users to send in emails to the tracker, but not access the web interface.
let some users edit the details of all users

  Create a new Role called "User Admin" which has the Permission for editing users:

      db.security.addRole(name='User Admin', description='Managing users')
      p = db.security.getPermission('Edit', 'user')
      db.security.addPermissionToRole('User Admin', p)

  and assign the Role to the users who need the permission.

## Web Interface

- Repercussions of changing the tracker schema
- How requests are processed
- Determining web context
- The "home" Context
- Serving static content
- Performing actions in web requests
- Special form variables
- Default templates
- How the templates work
  - Basic Templating Actions
  - Templating Expressions
  - Template Macros
- Information available to templates
  - The context variable
    - Hyperdb class wrapper
    - Hyperdb item wrapper
    - Hyperdb property wrapper
  - The request variable
    - The form variable
  - The db variable
  - The templates variable
  - The repeat variable
  - The utils variable
    - Batching
- Displaying Properties
- Index Views
  - Index View Specifiers
- Searching Views
- Item Views
  - Editor Section
    - Form values
  - Spool Section
  - History Section
- Defining new web actions
  - Define the new action class
  - Register the action class
  - Use the new action
  - Actions may return content to the user
- 8-bit character set support in Web interface

The web interface is provided by the `roundup.cgi.client` module and is used by `roundup.cgi`, `roundup-server` and `ZRoundup` (`ZRoundup` is broken, until further notice). In all cases, we determine which tracker is being accessed (the first part of the URL path inside the scope of the CGI handler) and pass control on to the `roundup.cgi.client.Client` class - which handles the rest of the access through its `main()` method. This means that you can do pretty much anything you want as a web interface to your tracker.

### Repercussions of changing the tracker schema

If you choose to change the tracker schema you will need to ensure the web interface knows about it:

1. Index, item and search pages for the relevant classes may need to have properties added or removed,
2. The "page" template may require links to be changed, as might the "home" page's content arguments.

### How requests are processed

The basic processing of a web request proceeds as follows:

1. figure out who we are, defaulting to the "anonymous" user
2. figure out what the request is for - we call this the "context"
3. handle any requested action (item edit, search, ...)
4. render the template requested by the context, resulting in HTML output

In some situations, exceptions occur:

- HTTP Redirect (generally raised by an action)

- SendFile (generally raised by `determine_context`)

    here we serve up a FileClass "content" property

- SendStaticFile (generally raised by `determine_context`)

    here we serve up a file from the tracker "html" directory

- Unauthorised (generally raised by an action)

    here the action is cancelled, the request is rendered and an error message is displayed indicating that permission was not granted for the action to take place

- NotFound (raised wherever it needs to be)

    this exception percolates up to the CGI interface that called the client

### Determining web context

To determine the "context" of a request, we look at the URL and the special request variable `@template`. The URL path after the tracker identifier is examined. Typical URL paths look like:

1. `/tracker/issue`
2. `/tracker/issue1`
3. `/tracker/@@file/style.css`
4. `/cgi-bin/roundup.cgi/tracker/file1`
5. `/cgi-bin/roundup.cgi/tracker/file1/kitten.png`

where the "tracker identifier" is "tracker" in the above cases. That means we're looking at "issue", "issue1", "@@file/style.css", "file1" and "file1/kitten.png" in the cases above. The path is generally only one entry long - longer paths are handled differently.

1. if there is no path, then we are in the "home" context. See the "home" context below for more information about how it may be used.
2. if the path starts with "@@file" (as in example 3, "/tracker/@@file/style.css"), then the additional path entry, "style.css" specifies the filename of a static file we're to serve up from the tracker TEMPLATES (or STATIC_FILES, if configured) directory. This is usually the tracker's "html" directory. Raises a SendStaticFile exception.
3. if there is something in the path (as in example 1, "issue"), it identifies the tracker class we're to display.
4. if the path is an item designator (as in examples 2 and 4, "issue1" and "file1"), then we're to display a specific item.
5. if the path starts with an item designator and is longer than one entry (as in example 5, "file1/kitten.png"), then we're assumed to be handling an item of a `FileClass`, and the extra path information gives the filename that the client is going to label the download with (i.e. "file1/kitten.png" is nicer to download than "file1"). This raises a `SendFile` exception.

Both b. and e. stop before we bother to determine the template we're going to use. That's because they don't actually use templates.

The template used is specified by the `@template` CGI variable, which defaults to:

- only classname suplied: "index"
- full item designator supplied: "item"

### The "home" Context

The "home" context is special because it allows you to add templated pages to your tracker that don't rely on a class or item (ie. an issues list or specific issue).

Let's say you wish to add frames to control the layout of your tracker's interface. You'd probably have:

- A top-level frameset page. This page probably wouldn't be templated, so it could be served as a static file (see serving static content)

- A sidebar frame that is templated. Let's call this page "home.navigation.html" in your tracker's "html" directory. To load that page up, you use the URL:

  > <tracker url>/home?@template=navigation

### Serving static content

See the previous section determining web context where it describes `@@file` paths.

### Performing actions in web requests

When a user requests a web page, they may optionally also request for an action to take place. As described in how requests are processed, the action is performed before the requested page is generated. Actions are triggered by using a `@action` CGI variable, where the value is one of:

login
  Attempt to log a user in.
logout
  Log the user out - make them "anonymous".
register
  Attempt to create a new user based on the contents of the form and then log them in.
edit
  Perform an edit of an item in the database. There are some special form variables you may use.
new
  Add a new item to the database. You may use the same special form variables as in the "edit" action.
retire
  Retire the item in the database.
editCSV
  Performs an edit of all of a class' items in one go. See also the class.csv templating method which generates the CSV data to be edited, and the `'_generic.index'` template which uses both of these features.
search

  Mangle some of the form variables:

  - Set the form ":filter" variable based on the values of the filter variables - if they're set to anything other than "dontcare" then add them to :filter.
  - Also handle the ":queryname" variable and save off the query to the user's query list.

Each of the actions is implemented by a corresponding `*XxxAction*` (where "Xxx" is the name of the action) class in the `roundup.cgi.actions` module. These classes are registered with `roundup.cgi.client.Client`. If you need to define new actions, you may add them there (see defining new web actions).

Each action class also has a `*permission*` method which determines whether the action is permissible given the current user. The base permission checks for each action are:

login
  Determine whether the user has the "Web Access" Permission.
logout
  No permission checks are made.
register
  Determine whether the user has the ("Create", "user") Permission.
edit
  Determine whether the user has permission to edit this item. If we're editing the "user" class, users are allowed to edit their own details - unless they try to edit the "roles" property, which requires the special Permission "Web Roles".
new
  Determine whether the user has permission to create this item. No additional property checks are made. Additionally, new user items may be created if the user has the ("Create", "user") Permission.
editCSV
  Determine whether the user has permission to edit this class.
search
  Determine whether the user has permission to view this class.

### Special form variables

Item properties and their values are edited with html FORM variables and their values. You can:

- Change the value of some property of the current item.
- Create a new item of any class, and edit the new item's properties,
- Attach newly created items to a multilink property of the current item.
- Remove items from a multilink property of the current item.
- Specify that some properties are required for the edit operation to be successful.
- Set up user interface locale.

These operations will only take place if the form action (the `@action` variable) is "edit" or "new".

In the following, <bracketed> values are variable, "@" may be either ":" or "@", and other text "required" is fixed.

Two special form variables are used to specify user language preferences:

`@language`
  value may be locale name or `none`. If this variable is set to locale name, web interface language is changed to given value (provided that appropriate translation is available), the value is stored in the browser cookie and will be used for all following requests. If value is `none` the cookie is removed and the language is changed to the tracker default, set up in the tracker configuration or OS environment.
`@charset`
  value may be character set name or `none`. Character set name is stored in the browser cookie and sets output encoding for all HTML pages generated by Roundup. If value is `none` the cookie is removed and HTML output is reset to Roundup internal encoding (UTF-8).

Most properties are specified as form variables:

`<propname>`
  property on the current context item
`<designator>"@"<propname>`
  property on the indicated item (for editing related information)

Designators name a specific item of a class.

`<classname><N>`
  Name an existing item of class <classname>.
`<classname>"-"<N>`
  Name the <N>th new item of class <classname>. If the form submission is successful, a new item of <classname> is created. Within the submitted form, a particular designator of this form always refers to the same new item.

Once we have determined the "propname", we look at it to see if it's special:

`@required`

  The associated form value is a comma-separated list of property names that must be specified when the form is submitted for the edit operation to succeed.

  When the <designator> is missing, the properties are for the current context item. When <designator> is present, they are for the item specified by <designator>.

  The "@required" specifier must come before any of the properties it refers to are assigned in the form.

`@remove@<propname>=id(s)` or `@add@<propname>=id(s)`
  The "@add@" and "@remove@" edit actions apply only to Multilink properties. The form value must be a comma-separate list of keys for the class specified by the simple form variable. The listed items are added to (respectively, removed from) the specified property.
`@link@<propname>=<designator>`
  If the edit action is "@link@", the simple form variable must specify a Link or Multilink property. The form value is a comma-separated list of designators. The item corresponding to each designator is linked to the property given by simple form variable.
None of the above (ie. just a simple form value)

  The value of the form variable is converted appropriately, depending on the type of the property.

  For a Link('klass') property, the form value is a single key for 'klass', where the key field is specified in schema.py.

  For a Multilink('klass') property, the form value is a comma-separated list of keys for 'klass', where the key field is specified in schema.py.

  Note that for simple-form-variables specifiying Link and Multilink properties, the linked-to class must have a key field.

  For a String() property specifying a filename, the file named by the form value is uploaded. This means we try to set additional properties "filename" and "type" (if they are valid for the class). Otherwise, the property is set to the form value.

  For Date(), Interval(), Boolean(), and Number() properties, the form value is converted to the appropriate

Any of the form variables may be prefixed with a classname or designator.

Two special form values are supported for backwards compatibility:

@note

  This is equivalent to:

      @link@messages=msg-1
      msg-1@content=value

  except that in addition, the "author" and "date" properties of "msg-1" are set to the userid of the submitter, and the current time, respectively.

@file

  This is equivalent to:

      @link@files=file-1
      file-1@content=value

  The String content value is handled as described above for file uploads.

If both the "@note" and "@file" form variables are specified, the action:

    @link@msg-1@files=file-1

is also performed.

We also check that FileClass items have a "content" property with actual content, otherwise we remove them from all_props before returning.

### Default templates

The default templates are html4 compliant. If you wish to change them to be xhtml compliant, you'll need to change the `html_version` configuration variable in `config.ini` to `'xhtml'` instead of `'html4'`.

Most customisation of the web view can be done by modifying the templates in the tracker `'html'` directory. There are several types of files in there. The minimal template includes:

page.html
  This template usually defines the overall look of your tracker. When you view an issue, it appears inside this template. When you view an index, it also appears inside this template. This template defines a macro called "icing" which is used by almost all other templates as a coating for their content, using its "content" slot. It also defines the "head_title" and "body_title" slots to allow setting of the page title.
home.html
  the default page displayed when no other page is indicated by the user
home.classlist.html
  a special version of the default page that lists the classes in the tracker
classname.item.html
  displays an item of the classname class
classname.index.html
  displays a list of classname items
classname.search.html
  displays a search page for classname items
_generic.index.html
  used to display a list of items where there is no `*classname*.index` available
_generic.help.html
  used to display a "class help" page where there is no `*classname*.help`
user.register.html
  a special page just for the user class, that renders the registration page
style.css.html
  a static file that is served up as-is

The classic template has a number of additional templates.

Remember that you can create any template extension you want to, so if you just want to play around with the templating for new issues, you can copy the current "issue.item" template to "issue.test", and then access the test template using the "@template" URL argument:

    http://your.tracker.example/tracker/issue?@template=test

and it won't affect your users using the "issue.item" template.

### How the templates work

#### Basic Templating Actions

Roundup's templates consist of special attributes on the HTML tags. These attributes form the Template Attribute Language, or TAL. The basic TAL commands are:

tal:define="variable expression; variable expression; ..."

  Define a new variable that is local to this tag and its contents. For example:

      <html tal:define="title request/description">
       <head><title tal:content="title"></title></head>
      </html>

  In this example, the variable "title" is defined as the result of the expression "request/description". The "tal:content" command inside the <html> tag may then use the "title" variable.

tal:condition="expression"

  Only keep this tag and its contents if the expression is true. For example:

      <p tal:condition="python:request.user.hasPermission('View', 'issue')">
       Display some issue information.
      </p>

  In the example, the <p> tag and its contents are only displayed if the user has the "View" permission for issues. We consider the number zero, a blank string, an empty list, and the built-in variable nothing to be false values. Nearly every other value is true, including non-zero numbers, and strings with anything in them (even spaces!).

tal:repeat="variable expression"

  Repeat this tag and its contents for each element of the sequence that the expression returns, defining a new local variable and a special "repeat" variable for each element. For example:

      <tr tal:repeat="u user/list">
       <td tal:content="u/id"></td>
       <td tal:content="u/username"></td>
       <td tal:content="u/realname"></td>
      </tr>

  The example would iterate over the sequence of users returned by "user/list" and define the local variable "u" for each entry. Using the repeat command creates a new variable called "repeat" which you may access to gather information about the iteration. See the section below on the repeat variable.

tal:replace="expression"

  Replace this tag with the result of the expression. For example:

      <span tal:replace="request/user/realname" />

  The example would replace the <span> tag and its contents with the user's realname. If the user's realname was "Bruce", then the resultant output would be "Bruce".

tal:content="expression"

  Replace the contents of this tag with the result of the expression. For example:

      <span tal:content="request/user/realname">user's name appears here
      </span>

  The example would replace the contents of the <span> tag with the user's realname. If the user's realname was "Bruce" then the resultant output would be "<span>Bruce</span>".

tal:attributes="attribute expression; attribute expression; ..."

  Set attributes on this tag to the results of expressions. For example:

      <a tal:attributes="href string:user${request/user/id}">My Details</a>

  In the example, the "href" attribute of the <a> tag is set to the value of the "string:user${request/user/id}" expression, which will be something like "user123".

tal:omit-tag="expression"

  Remove this tag (but not its contents) if the expression is true. For example:

      <span tal:omit-tag="python:1">Hello, world!</span>

  would result in output of:

      Hello, world!

Note that the commands on a given tag are evaulated in the order above, so define comes before condition, and so on.

Additionally, you may include tags such as <tal:block>, which are removed from output. Its content is kept, but the tag itself is not (so don't go using any "tal:attributes" commands on it). This is useful for making arbitrary blocks of HTML conditional or repeatable (very handy for repeating multiple table rows, which would othewise require an illegal tag placement to effect the repeat).

#### Templating Expressions

Templating Expressions are covered by Template Attribute Language Expression Syntax, or TALES. The expressions you may use in the attribute values may be one of the following forms:

Path Expressions - eg. `item/status/checklist`

  These are object attribute / item accesses. Roughly speaking, the path `item/status/checklist` is broken into parts `item`, `status` and `checklist`. The `item` part is the root of the expression. We then look for a `status` attribute on `item`, or failing that, a `status` item (as in `item['status']`). If that fails, the path expression fails. When we get to the end, the object we're left with is evaluated to get a string - if it is a method, it is called; if it is an object, it is stringified. Path expressions may have an optional `path:` prefix, but they are the default expression type, so it's not necessary.

  If an expression evaluates to `default`, then the expression is "cancelled" - whatever HTML already exists in the template will remain (tag content in the case of `tal:content`, attributes in the case of `tal:attributes`).

  If an expression evaluates to `nothing` then the target of the expression is removed (tag content in the case of `tal:content`, attributes in the case of `tal:attributes` and the tag itself in the case of `tal:replace`).

  If an element in the path may not exist, then you can use the `|` operator in the expression to provide an alternative. So, the expression `request/form/foo/value | default` would simply leave the current HTML in place if the "foo" form variable doesn't exist.

  You may use the python function `path`, as in `path("item/status")`, to embed path expressions in Python expressions.

String Expressions - eg. `string:hello ${user/name}`
  These expressions are simple string interpolations - though they can be just plain strings with no interpolation if you want. The expression in the `${ ... }` is just a path expression as above.
Python Expressions - eg. `python: 1+1`
  These expressions give the full power of Python. All the "root level" variables are available, so `python:item.status.checklist()` would be equivalent to `item/status/checklist`, assuming that `checklist` is a method.

Modifiers:

structure - eg. `structure python:msg.content.plain(hyperlink=1)`
  The result of expressions are normally escaped to be safe for HTML display (all "<", ">" and "&" are turned into special entities). The `structure` expression modifier turns off this escaping - the result of the expression is now assumed to be HTML, which is passed to the web browser for rendering.
not: - eg. `not:python:1=1`
  This simply inverts the logical true/false value of another expression.

#### Template Macros

Macros are used in Roundup to save us from repeating the same common page stuctures over and over. The most common (and probably only) macro you'll use is the "icing" macro defined in the "page" template.

Macros are generated and used inside your templates using special attributes similar to the basic templating actions. In this case, though, the attributes belong to the Macro Expansion Template Attribute Language, or METAL. The macro commands are:

metal:define-macro="macro name"

  Define that the tag and its contents are now a macro that may be inserted into other templates using the use-macro command. For example:

      <html metal:define-macro="page">
       ...
      </html>

  defines a macro called "page" using the `<html>` tag and its contents. Once defined, macros are stored on the template they're defined on in the `macros` attribute. You can access them later on through the `templates` variable, eg. the most common `templates/page/macros/icing` to access the "page" macro of the "page" template.

metal:use-macro="path expression"

  Use a macro, which is identified by the path expression (see above). This will replace the current tag with the identified macro contents. For example:

      <tal:block metal:use-macro="templates/page/macros/icing">
       ...
      </tal:block>

      will replace the tag and its contents with the "page" macro of the
      "page" template.

metal:define-slot="slot name" and metal:fill-slot="slot name"

  To define dynamic parts of the macro, you define "slots" which may be filled when the macro is used with a use-macro command. For example, the `templates/page/macros/icing` macro defines a slot like so:

      <title metal:define-slot="head_title">title goes here</title>

  In your use-macro command, you may now use a fill-slot command like this:

      <title metal:fill-slot="head_title">My Title</title>

  where the tag that fills the slot completely replaces the one defined as the slot in the macro.

Note that you may not mix METAL and TAL commands on the same tag, but TAL commands may be used freely inside METAL-using tags (so your fill-slots tags may have all manner of TAL inside them).

### Information available to templates

This is implemented by `roundup.cgi.templating.RoundupPageTemplate`

The following variables are available to templates.

context
  The current context. This is either None, a hyperdb class wrapper or a hyperdb item wrapper
request
  Includes information about the current request, including:
    - the current index information (`filterspec`, `filter` args, `properties`, etc) parsed out of the form.
    - methods for easy filterspec link generation
    - "form" The current CGI form information as a mapping of form argument name to value (specifically a cgi.FieldStorage)
    - "env" the CGI environment variables
    - "base" the base URL for this instance
    - "user" a HTMLItem instance for the current user
    - "language" as determined by the browser or config
    - "classname" the current classname (possibly None)
    - "template" the current template (suffix, also possibly None)
config
  This variable holds all the values defined in the tracker config.ini file (eg. TRACKER_NAME, etc.)
db
  The current database, used to access arbitrary database items.
templates
  Access to all the tracker templates by name. Used mainly in use-macro commands.
utils
  This variable makes available some utility functions like batching.
nothing

  This is a special variable - if an expression evaluates to this, then the tag (in the case of a `tal:replace`), its contents (in the case of `tal:content`) or some attributes (in the case of `tal:attributes`) will not appear in the the output. So, for example:

      <span tal:attributes="class nothing">Hello, World!</span>

  would result in:

      <span>Hello, World!</span>

default

  Also a special variable - if an expression evaluates to this, then the existing HTML in the template will not be replaced or removed, it will remain. So:

      <span tal:replace="default">Hello, World!</span>

  would result in:

      <span>Hello, World!</span>

true, false
  Boolean constants that may be used in templating expressions instead of `python:1` and `python:0`.
i18n

  Internationalization service, providing two string translation methods:

  gettext (message)
    Return the localized translation of message
  ngettext (singular, plural, number)

    Like `gettext()`, but consider plural forms. If a translation is found, apply the plural formula to number, and return the resulting message (some languages have more than two plural forms). If no translation is found, return singular if number is 1; return plural otherwise.

    This function requires python2.3; in earlier python versions may not work as expected.

#### The context variable

The context variable is one of three things based on the current context (see determining web context for how we figure this out):

1. if we're looking at a "home" page, then it's None
2. if we're looking at a specific hyperdb class, it's a hyperdb class wrapper.
3. if we're looking at a specific hyperdb item, it's a hyperdb item wrapper.

If the context is not None, we can access the properties of the class or item. The only real difference between cases 2 and 3 above are:

1. the properties may have a real value behind them, and this will appear if the property is displayed through `context/property` or `context/property/field`.
2. the context's "id" property will be a false value in the second case, but a real, or true value in the third. Thus we can determine whether we're looking at a real item from the hyperdb by testing "context/id".

##### Hyperdb class wrapper

This is implemented by the `roundup.cgi.templating.HTMLClass` class.

This wrapper object provides access to a hyperb class. It is used primarily in both index view and new item views, but it's also usable anywhere else that you wish to access information about a class, or the items of a class, when you don't have a specific item of that class in mind.

We allow access to properties. There will be no "id" property. The value accessed through the property will be the current value of the same name from the CGI form.

There are several methods available on these wrapper objects:

Method | Description
--- | ---
properties | return a hyperdb property wrapper for all of this class's properties.
list | lists all of the active (not retired) items in the class.
csv | return the items of this class as a chunk of CSV text.
propnames | lists the names of the properties of this class.

filter

lists of items from this class, filtered and sorted. Two options are avaible for sorting:

1. by the current request filterspec/filter/sort/group args

2. by the "filterspec", "sort" and "group" keyword args. "filterspec" is `{propname: value(s)}`. "sort" and "group" are an optionally empty list `[(dir, prop)]` where dir is '+', '-' or None and prop is a prop name or None.

   The propname in filterspec and prop in a sort/group spec may be transitive, i.e., it may contain properties of the form link.link.link.name.

eg. All issues with a priority of "1" with messages added in the last week, sorted by activity date: `issue.filter(filterspec={"priority": "1", 'messages.creation' : '.-1w;'}, sort=[('activity', '+')])`

filter_sql | Only in SQL backends Lists the items that match the SQL provided. The SQL is a complete "select" statement. The SQL select must include the item id as the first column. This function does not filter out retired items, add on a where clause "__retired__ <> 1" if you don't want retired nodes.

classhelp

display a link to a javascript popup containing this class' "help" template.

This generates a link to a popup window which displays the properties indicated by "properties" of the class named by "classname". The "properties" should be a comma-separated list (eg. 'id,name,description'). Properties defaults to all the properties of a class (excluding id, creator, created and activity).

You may optionally override the "label" displayed, the "width", the "height", the number of items per page ("pagesize") and the field on which the list is sorted ("sort").

With the "filter" arg it is possible to specify a filter for which items are supposed to be displayed. It has to be of the format "<field>=<values>;<field>=<values>;...".

The popup window will be resizable and scrollable.

If the "property" arg is given, it's passed through to the javascript help_window function. This allows updating of a property in the calling HTML page.

If the "form" arg is given, it's passed through to the javascript help_window function - it's the name of the form the "property" belongs to.

submit | generate a submit button (and action hidden element)
renderWith | render this class with the given template.
history | returns 'New node - no history' :)
is_edit_ok | is the user allowed to Edit the current class?
is_view_ok | is the user allowed to View the current class?

Note that if you have a property of the same name as one of the above methods, you'll need to access it using a python "item access" expression. For example:

    python:context['list']

will access the "list" property, rather than the list method.

##### Hyperdb item wrapper

This is implemented by the `roundup.cgi.templating.HTMLItem` class.

This wrapper object provides access to a hyperb item.

We allow access to properties. There will be no "id" property. The value accessed through the property will be the current value of the same name from the CGI form.

There are several methods available on these wrapper objects:

Method | Description
--- | ---
submit | generate a submit button (and action hidden element)
journal | return the journal of the current item (not implemented)
history | render the journal of the current item as HTML
renderQueryForm | specific to the "query" class - render the search form for the query

hasPermission

specific to the "user" class - determine whether the user has a Permission. The signature is:

    hasPermission(self, permission, [classname=],
        [property=], [itemid=])

where the classname defaults to the current context.

hasRole

specific to the "user" class - determine whether the user has a Role. The signature is:

    hasRole(self, rolename)

is_edit_ok | is the user allowed to Edit the current item?
is_view_ok | is the user allowed to View the current item?
is_retired | is the item retired?
download_url | generate a url-quoted link for download of FileClass item contents (ie. file<id>/<name>)
copy_url | generate a url-quoted link for creating a copy of this item. By default, the copy will acquire all properties of the current item except for `messages` and `files`. This can be overridden by passing `exclude` argument which contains a list (or any iterable) of property names that shall not be copied. Database-driven properties like `id` or `activity` cannot be copied.

Note that if you have a property of the same name as one of the above methods, you'll need to access it using a python "item access" expression. For example:

    python:context['journal']

will access the "journal" property, rather than the journal method.

##### Hyperdb property wrapper

This is implemented by subclasses of the `roundup.cgi.templating.HTMLProperty` class (`HTMLStringProperty`, `HTMLNumberProperty`, and so on).

This wrapper object provides access to a single property of a class. Its value may be either:

1. if accessed through a hyperdb item wrapper, then it's a value from the hyperdb
2. if access through a hyperdb class wrapper, then it's a value from the CGI form

The property wrapper has some useful attributes:

Attribute | Description
--- | ---
_name | the name of the property
_value | the value of the property if any - this is the actual value retrieved from the hyperdb for this property

There are several methods available on these wrapper objects:

Method | Description
--- | ---

plain

render a "plain" representation of the property. This method may take two arguments:

escape

  If true, escape the text so it is HTML safe (default: no). The reason this defaults to off is that text is usually escaped at a later stage by the TAL commands, unless the "structure" option is used in the template. The following `tal:content` expressions are all equivalent:

      "structure python:msg.content.plain(escape=1)"
      "python:msg.content.plain()"
      "msg/content/plain"
      "msg/content"

  Usually you'll only want to use the escape option in a complex expression.

hyperlink

  If true, turn URLs, email addresses and hyperdb item designators in the text into hyperlinks (default: no). Note that you'll need to use the "structure" TAL option if you want to use this `tal:content` expression:

      "structure python:msg.content.plain(hyperlink=1)"

  The text is automatically HTML-escaped before the hyperlinking transformation done in the plain() method.

hyperlinked

The same as msg.content.plain(hyperlink=1), but nicer:

    "structure msg/content/hyperlinked"

field

render an appropriate form edit field for the property - for most types this is a text entry box, but for Booleans it's a tri-state yes/no/neither selection. This method may take some arguments:

size
  Sets the width in characters of the edit field
format (Date properties only)
  Sets the format of the date in the field - uses the same format string argument as supplied to the `pretty` method below.
popcal (Date properties only)
  Include the Javascript-based popup calendar for date selection. Defaults to on.

stext | only on String properties - render the value of the property as StructuredText (requires the StructureText module to be installed separately)
multiline | only on String properties - render a multiline form edit field for the property
email | only on String properties - render the value of the property as an obscured email address
confirm | only on Password properties - render a second form edit field for the property, used for confirmation that the user typed the password correctly. Generates a field with name "name:confirm".
now | only on Date properties - return the current date as a new property
reldate | only on Date properties - render the interval between the date and now

local

only on Date properties - return this date as a new property with some timezone offset, for example:

    python:context.creation.local(10)

will render the date with a +10 hour offset.

pretty

Date properties - render the date as "dd Mon YYYY" (eg. "19 Mar 2004"). Takes an optional format argument, for example:

    python:context.activity.pretty('%Y-%m-%d')

Will format as "2004-03-19" instead.

Interval properties - render the interval in a pretty format (eg. "yesterday"). The format arguments are those used in the standard `strftime` call (see the Python Library Reference: time module)

popcal

Generate a link to a popup calendar which may be used to edit the date field, for example:

    <span tal:replace="structure context/due/popcal" />

you still need to include the `field` for the property, so typically you'd have:

    <span tal:replace="structure context/due/field" />
    <span tal:replace="structure context/due/popcal" />

menu

only on Link and Multilink properties - render a form select list for this property. Takes a number of optional arguments

size
  is used to limit the length of the list labels
height
  is used to set the <select> tag's "size" attribute
showid
  includes the item ids in the list labels
additional
  lists properties which should be included in the label
sort_on
  indicates the property to sort the list on as (direction, (direction, property) where direction is '+' or '-'. A single string with the direction prepended may be used. For example: ('-', 'order'), '+name'.
value
  gives a default value to preselect in the menu

The remaining keyword arguments are used as conditions for filtering the items in the list - they're passed as the "filterspec" argument to a Class.filter() call. For example:

    <span tal:replace="structure context/status/menu" />

    <span tal:replace="python:context.status.menu(order='+name",
                          value='chatting',
                          filterspec={'status': '1,2,3,4'}" />

sorted

only on Multilink properties - produce a list of the linked items sorted by some property, for example:

    python:context.files.sorted('creation')

Will list the files by upload date.

reverse | only on Multilink properties - produce a list of the linked items in reverse order
isset | returns True if the property has been set to a value

All of the above functions perform checks for permissions required to display or edit the data they are manipulating. The simplest case is editing an issue title. Including the expression:

    context/title/field

Will present the user with an edit field, if they have edit permission. If not, then they will be presented with a static display if they have view permission. If they don't even have view permission, then an error message is raised, preventing the display of the page, indicating that they don't have permission to view the information.

#### The request variable

This is implemented by the `roundup.cgi.templating.HTMLRequest` class.

The request variable is packed with information about the current request.

Variable | Holds
--- | ---
form | the CGI form as a cgi.FieldStorage
env | the CGI environment variables
base | the base URL for this tracker
user | a HTMLUser instance for this user
classname | the current classname (possibly None)
template | the current template (suffix, also possibly None)
form | the current CGI form variables in a FieldStorage

Index page specific variables (indexing arguments)

Variable | Holds
--- | ---
columns | dictionary of the columns to display in an index page
show | a convenience access to columns - request/show/colname will be true if the columns should be displayed, false otherwise
sort | index sort columns [(direction, column name)]
group | index grouping properties [(direction, column name)]
filter | properties to filter the index on
filterspec | values to filter the index on (property=value, eg `priority=1` or `messages.author=42`
search_text | text to perform a full-text search on for an index

There are several methods available on the request variable:

Method | Description
--- | ---
description | render a description of the request - handle for the page title
indexargs_form | render the current index args as form elements
indexargs_url | render the current index args as a URL
base_javascript | render some javascript that is used by other components of the templating
batch | run the current index args through a filter and return a list of items (see hyperdb item wrapper, and batching)

##### The form variable

The form variable is a bit special because it's actually a python FieldStorage object. That means that you have two ways to access its contents. For example, to look up the CGI form value for the variable "name", use the path expression:

    request/form/name/value

or the python expression:

    python:request.form['name'].value

Note the "item" access used in the python case, and also note the explicit "value" attribute we have to access. That's because the form variables are stored as MiniFieldStorages. If there's more than one "name" value in the form, then the above will break since `request/form/name` is actually a list of MiniFieldStorages. So it's best to know beforehand what you're dealing with.

#### The db variable

This is implemented by the `roundup.cgi.templating.HTMLDatabase` class.

Allows access to all hyperdb classes as attributes of this variable. If you want access to the "user" class, for example, you would use:

    db/user
    python:db.user

Also, the current id of the current user is available as `db.getuid()`. This isn't so useful in templates (where you have `request/user`), but it can be useful in detectors or interfaces.

The access results in a hyperdb class wrapper.

#### The templates variable

This is implemented by the `roundup.cgi.templating.Templates` class.

This variable doesn't have any useful methods defined. It supports being used in expressions to access the templates, and consequently the template macros. You may access the templates using the following path expression:

    templates/name

or the python expression:

    templates[name]

where "name" is the name of the template you wish to access. The template has one useful attribute, namely "macros". To access a specific macro (called "macro_name"), use the path expression:

    templates/name/macros/macro_name

or the python expression:

    templates[name].macros[macro_name]

#### The repeat variable

The repeat variable holds an entry for each active iteration. That is, if you have a `tal:repeat="user db/users"` command, then there will be a repeat variable entry called "user". This may be accessed as either:

    repeat/user
    python:repeat['user']

The "user" entry has a number of methods available for information:

Method | Description
--- | ---
first | True if the current item is the first in the sequence.
last | True if the current item is the last in the sequence.
even | True if the current item is an even item in the sequence.
odd | True if the current item is an odd item in the sequence.
number | Current position in the sequence, starting from 1.
letter | Current position in the sequence as a letter, a through z, then aa through zz, and so on.
Letter | Same as letter(), except uppercase.
roman | Current position in the sequence as lowercase roman numerals.
Roman | Same as roman(), except uppercase.

#### The utils variable

This is implemented by the `roundup.cgi.templating.TemplatingUtils` class, but it may be extended as described below.

Method | Description
--- | ---
Batch | return a batch object using the supplied list
url_quote | quote some text as safe for a URL (ie. space, %, ...)
html_quote | quote some text as safe in HTML (ie. <, >, ...)
html_calendar | renders an HTML calendar used by the `_generic.calendar.html` template (itself invoked by the popupCalendar DateHTMLProperty method

You may add additional utility methods by writing them in your tracker `extensions` directory and registering them with the templating system using `instance.registerUtil` (see adding a time log to your issues for an example of this).

##### Batching

Use Batch to turn a list of items, or item ids of a given class, into a series of batches. Its usage is:

    python:utils.Batch(sequence, size, start, end=0, orphan=0,
    overlap=0)

or, to get the current index batch:

    request/batch

The parameters are:

Parameter | Usage
--- | ---
sequence | a list of HTMLItems
size | how big to make the sequence.
start | where to start (0-indexed) in the sequence.
end | where to end (0-indexed) in the sequence.
orphan | if the next batch would contain less items than this value, then it is combined with this batch
overlap | the number of items shared between adjacent batches

All of the parameters are assigned as attributes on the batch object. In addition, it has several more attributes:

Attribute | Description
--- | ---
start | indicates the start index of the batch. Unlike the argument, is a 1-based index (I know, lame)
first | indicates the start index of the batch as a 0-based index
length | the actual number of elements in the batch
sequence_length | the length of the original, unbatched, sequence.

And several methods:

Method | Description
--- | ---
previous | returns a new Batch with the previous batch settings
next | returns a new Batch with the next batch settings
propchanged | detect if the named property changed on the current item when compared to the last item

An example of batching:

    <table class="otherinfo">
     <tr><th colspan="4" class="header">Existing Keywords</th></tr>
     <tr tal:define="keywords db/keyword/list"
         tal:repeat="start python:range(0, len(keywords), 4)">
      <td tal:define="batch python:utils.Batch(keywords, 4, start)"
          tal:repeat="keyword batch" tal:content="keyword/name">
          keyword here</td>
     </tr>
    </table>

... which will produce a table with four columns containing the items of the "keyword" class (well, their "name" anyway).

### Displaying Properties

Properties appear in the user interface in three contexts: in indices, in editors, and as search arguments. For each type of property, there are several display possibilities. For example, in an index view, a string property may just be printed as a plain string, but in an editor view, that property may be displayed in an editable field.

### Index Views

This is one of the class context views. It is also the default view for classes. The template used is "classname.index".

#### Index View Specifiers

An index view specifier (URL fragment) looks like this (whitespace has been added for clarity):

    /issue?status=unread,in-progress,resolved&
        keyword=security,ui&
        @group=priority,-status&
        @sort=-activity&
        @filters=status,keyword&
        @columns=title,status,fixer

The index view is determined by two parts of the specifier: the layout part and the filter part. The layout part consists of the query parameters that begin with colons, and it determines the way that the properties of selected items are displayed. The filter part consists of all the other query parameters, and it determines the criteria by which items are selected for display. The filter part is interactively manipulated with the form widgets displayed in the filter section. The layout part is interactively manipulated by clicking on the column headings in the table.

The filter part selects the union of the sets of items with values matching any specified Link properties and the intersection of the sets of items with values matching any specified Multilink properties.

The example specifies an index of "issue" items. Only items with a "status" of either "unread" or "in-progress" or "resolved" are displayed, and only items with "keyword" values including both "security" and "ui" are displayed. The items are grouped by priority arranged in ascending order and in descending order by status; and within groups, sorted by activity, arranged in descending order. The filter section shows filters for the "status" and "keyword" properties, and the table includes columns for the "title", "status", and "fixer" properties.

Argument | Description
--- | ---
@sort | sort by prop name, optionally preceeded with '-' to give descending or nothing for ascending sorting. Several properties can be specified delimited with comma. Internally a search-page using several sort properties may use @sort0, @sort1 etc. with option @sortdir0, @sortdir1 etc. for the direction of sorting (a non-empty value of sortdir0 specifies reverse order).
@group | group by prop name, optionally preceeded with '-' or to sort in descending or nothing for ascending order. Several properties can be specified delimited with comma. Internally a search-page using several grouping properties may use @group0, @group1 etc. with option @groupdir0, @groupdir1 etc. for the direction of grouping (a non-empty value of groupdir0 specifies reverse order).
@columns | selects the columns that should be displayed. Default is all.
@filter | indicates which properties are being used in filtering. Default is none.
propname | selects the values the item properties given by propname must have (very basic search/filter).
@search_text | if supplied, performs a full-text search (message bodies, issue titles, etc)

### Searching Views

Note

if you add a new column to the `@columns` form variable potentials then you will need to add the column to the appropriate index views template so that it is actually displayed.

This is one of the class context views. The template used is typically "classname.search". The form on this page should have "search" as its `@action` variable. The "search" action:

- sets up additional filtering, as well as performing indexed text searching
- sets the `@filter` variable correctly
- saves the query off if `@query_name` is set.

The search page should lay out any fields that you wish to allow the user to search on. If your schema contains a large number of properties, you should be wary of making all of those properties available for searching, as this can cause confusion. If the additional properties are Strings, consider having their value indexed, and then they will be searchable using the full text indexed search. This is both faster, and more useful for the end user.

If the search view does specify the "search" `@action`, then it may also provide an additional argument:

Argument | Description
--- | ---
@query_name | if supplied, the index parameters (including @search_text) will be saved off as a the query item and registered against the user's queries property. Note that the classic template schema has this ability, but the minimal template schema does not.

### Item Views

The basic view of a hyperdb item is provided by the "classname.item" template. It generally has three sections; an "editor", a "spool" and a "history" section.

#### Editor Section

The editor section is used to manipulate the item - it may be a static display if the user doesn't have permission to edit the item.

Here's an example of a basic editor template (this is the default "classic" template issue item edit form - from the "issue.item.html" template):

    <table class="form">
    <tr>
     <th>Title</th>
     <td colspan="3" tal:content="structure python:context.title.field(size=60)">title</td>
    </tr>

    <tr>
     <th>Priority</th>
     <td tal:content="structure context/priority/menu">priority</td>
     <th>Status</th>
     <td tal:content="structure context/status/menu">status</td>
    </tr>

    <tr>
     <th>Superseder</th>
     <td>
      <span tal:replace="structure python:context.superseder.field(showid=1, size=20)" />
      <span tal:replace="structure python:db.issue.classhelp('id,title')" />
      <span tal:condition="context/superseder">
       <br>View: <span tal:replace="structure python:context.superseder.link(showid=1)" />
      </span>
     </td>
     <th>Nosy List</th>
     <td>
      <span tal:replace="structure context/nosy/field" />
      <span tal:replace="structure python:db.user.classhelp('username,realname,address,phone')" />
     </td>
    </tr>

    <tr>
     <th>Assigned To</th>
     <td tal:content="structure context/assignedto/menu">
      assignedto menu
     </td>
     <td>&nbsp;</td>
     <td>&nbsp;</td>
    </tr>

    <tr>
     <th>Change Note</th>
     <td colspan="3">
      <textarea name=":note" wrap="hard" rows="5" cols="60"></textarea>
     </td>
    </tr>

    <tr>
     <th>File</th>
     <td colspan="3"><input type="file" name=":file" size="40"></td>
    </tr>

    <tr>
     <td>&nbsp;</td>
     <td colspan="3" tal:content="structure context/submit">
      submit button will go here
     </td>
    </tr>
    </table>

When a change is submitted, the system automatically generates a message describing the changed properties. As shown in the example, the editor template can use the ":note" and ":file" fields, which are added to the standard changenote message generated by Roundup.

##### Form values

We have a number of ways to pull properties out of the form in order to meet the various needs of:

1. editing the current item (perhaps an issue item)
2. editing information related to the current item (eg. messages or attached files)
3. creating new information to be linked to the current item (eg. time spent on an issue)

In the following, `<bracketed>` values are variable, ":" may be one of ":" or "@", and other text ("required") is fixed.

Properties are specified as form variables:

`<propname>`
  property on the current context item
`<designator>:<propname>`
  property on the indicated item (for editing related information)
`<classname>-<N>:<propname>`
  property on the Nth new item of classname (generally for creating new items to attach to the current item)

Once we have determined the "propname", we check to see if it is one of the special form values:

`@required`
  The named property values must be supplied or a ValueError will be raised.
`@remove@<propname>=id(s)`
  The ids will be removed from the multilink property.
`:add:<propname>=id(s)`
  The ids will be added to the multilink property.
`:link:<propname>=<designator>`
  Used to add a link to new items created during edit. These are collected and returned in `all_links`. This will result in an additional linking operation (either Link set or Multilink append) after the edit/create is done using `all_props` in `_editnodes`. The <propname> on the current item will be set/appended the id of the newly created item of class <designator> (where <designator> must be <classname>-<N>).

Any of the form variables may be prefixed with a classname or designator.

Two special form values are supported for backwards compatibility:

`:note`
  create a message (with content, author and date), linked to the context item. This is ALWAYS designated "msg-1".
`:file`
  create a file, attached to the current item and any message created by :note. This is ALWAYS designated "file-1".

#### Spool Section

The spool section lists related information like the messages and files of an issue.

TODO

#### History Section

The final section displayed is the history of the item - its database journal. This is generally generated with the template:

    <tal:block tal:replace="structure context/history" />

To be done:

The actual history entries of the item may be accessed for manual templating through the "journal" method of the item:

    <tal:block tal:repeat="entry context/journal">
     a journal entry
    </tal:block>

where each journal entry is an HTMLJournalEntry.

### Defining new web actions

You may define new actions to be triggered by the `@action` form variable. These are added to the tracker `extensions` directory and registered using `instance.registerAction`.

All the existing Actions are defined in `roundup.cgi.actions`.

Adding action classes takes three steps; first you define the new action class, then you register the action class with the cgi interface so it may be triggered by the `@action` form variable. Finally you use the new action in your HTML form.

See "setting up a "wizard" (or "druid") for controlled adding of issues" for an example.

#### Define the new action class

Create a new action class in your tracker's `extensions` directory, for example `myaction.py`:

    from roundup.cgi.actions import Action

    class MyAction(Action):
        def handle(self):
            ''' Perform some action. No return value is required.
            '''

The self.client attribute is an instance of `roundup.cgi.client.Client`. See the docstring of that class for details of what it can do.

The method will typically check the `self.form` variable's contents. It may then:

- add information to `self.client.ok_message` or `self.client.error_message`
- change the `self.client.template` variable to alter what the user will see next
- raise Unauthorised, SendStaticFile, SendFile, NotFound or Redirect exceptions (import them from roundup.cgi.exceptions)

#### Register the action class

The class is now written, but isn't available to the user until you register it with the following code appended to your `myaction.py` file:

    def init(instance):
        instance.registerAction('myaction', myActionClass)

This maps the action name "myaction" to the action class we defined.

#### Use the new action

In your HTML form, add a hidden form element like so:

    <input type="hidden" name="@action" value="myaction">

where "myaction" is the name you registered in the previous step.

#### Actions may return content to the user

Actions generally perform some database manipulation and then pass control on to the rendering of a template in the current context (see Determining web context for how that works.) Some actions will want to generate the actual content returned to the user. Action methods may return their own content string to be displayed to the user, overriding the templating step. In this situation, we assume that the content is HTML by default. You may override the content type indicated to the user by calling `setHeader`:

    self.client.setHeader('Content-Type', 'text/csv')

This example indicates that the value sent back to the user is actually comma-separated value content (eg. something to be loaded into a spreadsheet or database).

### 8-bit character set support in Web interface

The web interface uses UTF-8 default. It may be overridden in both forms and a browser cookie.

- In forms, use the `@charset` variable.
- To use the cookie override, have the `roundup_charset` cookie set.

In both cases, the value is a valid charset name (eg. `utf-8` or `kio8-r`).

Inside Roundup, all strings are stored and processed in utf-8. Unfortunately, some older browsers do not work properly with utf-8-encoded pages (e.g. Netscape Navigator 4 displays wrong characters in form fields). This version allows one to change the character set for http transfers. To do so, you may add the following code to your `page.html` template:

    <tal:block define="uri string:${request/base}${request/env/PATH_INFO}">
     <a tal:attributes="href python:request.indexargs_url(uri,
      {'@charset':'utf-8'})">utf-8</a>
     <a tal:attributes="href python:request.indexargs_url(uri,
      {'@charset':'koi8-r'})">koi8-r</a>
    </tal:block>

(substitute `koi8-r` with appropriate charset for your language). Charset preference is kept in the browser cookie `roundup_charset`.

`meta http-equiv` lines added to the tracker templates in version 0.6.0 should be changed to include actual character set name:

    <meta http-equiv="Content-Type"
     tal:attributes="content string:text/html;; charset=${request/client/charset}"
    />

The charset is also sent in the http header.

## Examples

- Changing what's stored in the database
  - Adding a new field to the classic schema
  - Adding a new constrained field to the classic schema
  - Adding a time log to your issues
  - Tracking different types of issues
- Using External User Databases
  - Using an external password validation source
  - Using a UN*X passwd file as the user database
  - Using an LDAP database for user information
- Changes to Tracker Behaviour
  - Preventing SPAM
  - Stop "nosy" messages going to people on vacation
  - Adding in state transition control
  - Blocking issues that depend on other issues
  - Add users to the nosy list based on the keyword
- Changes to Security and Permissions
  - Restricting the list of users that are assignable to a task
  - Users may only edit their issues
  - All users may only view and edit issues, files and messages they create
- Changes to the Web User Interface
  - Adding action links to the index page
  - Colouring the rows in the issue index according to priority
  - Editing multiple items in an index view
  - Displaying only message summaries in the issue display
  - Enabling display of either message summaries or the entire messages
  - Setting up a "wizard" (or "druid") for controlled adding of issues

### Changing what's stored in the database

The following examples illustrate ways to change the information stored in the database.

#### Adding a new field to the classic schema

This example shows how to add a simple field (a due date) to the default classic schema. It does not add any additional behaviour, such as enforcing the due date, or causing automatic actions to fire if the due date passes.

You add new fields by editing the `schema.py` file in you tracker's home. Schema changes are automatically applied to the database on the next tracker access (note that roundup-server would need to be restarted as it caches the schema).

1. Modify the `schema.py`:

       issue = IssueClass(db, "issue",
                       assignedto=Link("user"), keyword=Multilink("keyword"),
                       priority=Link("priority"), status=Link("status"),
                       due_date=Date())

2. Add an edit field to the `issue.item.html` template:

       <tr>
        <th>Due Date</th>
        <td tal:content="structure context/due_date/field" />
       </tr>

   If you want to show only the date part of due_date then do this instead:

       <tr>
        <th>Due Date</th>
        <td tal:content="structure python:context.due_date.field(format='%Y-%m-%d')" />
       </tr>

3. Add the property to the `issue.index.html` page:

       (in the heading row)
         <th tal:condition="request/show/due_date">Due Date</th>
       (in the data row)
         <td tal:condition="request/show/due_date"
             tal:content="i/due_date" />

   If you want format control of the display of the due date you can enter the following in the data row to show only the actual due date:

       <td tal:condition="request/show/due_date"
           tal:content="python:i.due_date.pretty('%Y-%m-%d')">&nbsp;</td>

4. Add the property to the `issue.search.html` page:

       <tr tal:define="name string:due_date">
         <th i18n:translate="">Due Date:</th>
         <td metal:use-macro="search_input"></td>
         <td metal:use-macro="column_input"></td>
         <td metal:use-macro="sort_input"></td>
         <td metal:use-macro="group_input"></td>
       </tr>

5. If you wish for the due date to appear in the standard views listed in the sidebar of the web interface then you'll need to add "due_date" to the columns and columns_showall lists in your `page.html`:

       columns string:id,activity,due_date,title,creator,status;
       columns_showall string:id,activity,due_date,title,creator,assignedto,status;

#### Adding a new constrained field to the classic schema

This example shows how to add a new constrained property (i.e. a selection of distinct values) to your tracker.

##### Introduction

To make the classic schema of Roundup useful as a TODO tracking system for a group of systems administrators, it needs an extra data field per issue: a category.

This would let sysadmins quickly list all TODOs in their particular area of interest without having to do complex queries, and without relying on the spelling capabilities of other sysadmins (a losing proposition at best).

##### Adding a field to the database

This is the easiest part of the change. The category would just be a plain string, nothing fancy. To change what is in the database you need to add some lines to the `schema.py` file of your tracker instance. Under the comment:

    # add any additional database schema configuration here

add:

    category = Class(db, "category", name=String())
    category.setkey("name")

Here we are setting up a chunk of the database which we are calling "category". It contains a string, which we are refering to as "name" for lack of a more imaginative title. (Since "name" is one of the properties that Roundup looks for on items if you do not set a key for them, it's probably a good idea to stick with it for new classes if at all appropriate.) Then we are setting the key of this chunk of the database to be that "name". This is equivalent to an index for database types. This also means that there can only be one category with a given name.

Adding the above lines allows us to create categories, but they're not tied to the issues that we are going to be creating. It's just a list of categories off on its own, which isn't much use. We need to link it in with the issues. To do that, find the lines in `schema.py` which set up the "issue" class, and then add a link to the category:

    issue = IssueClass(db, "issue", ... ,
        category=Multilink("category"), ... )

The `Multilink()` means that each issue can have many categories. If you were adding something with a one-to-one relationship to issues (such as the "assignedto" property), use `Link()` instead.

That is all you need to do to change the schema. The rest of the effort is fiddling around so you can actually use the new category.

##### Populating the new category class

If you haven't initialised the database with the `roundup-admin` "initialise" command, then you can add the following to the tracker `initial_data.py` under the comment:

    # add any additional database creation steps here - but only if you
    # haven't initialised the database with the admin "initialise" command

Add:

    category = db.getclass('category')
    category.create(name="scipy")
    category.create(name="chaco")
    category.create(name="weave")

If the database has already been initalised, then you need to use the `roundup-admin` tool:

    % roundup-admin -i <tracker home>
    Roundup <version> ready for input.
    Type "help" for help.
    roundup> create category name=scipy
    1
    roundup> create category name=chaco
    2
    roundup> create category name=weave
    3
    roundup> exit...
    There are unsaved changes. Commit them (y/N)? y

##### Setting up security on the new objects

By default only the admin user can look at and change objects. This doesn't suit us, as we want any user to be able to create new categories as required, and obviously everyone needs to be able to view the categories of issues for it to be useful.

We therefore need to change the security of the category objects. This is also done in `schema.py`.

There are currently two loops which set up permissions and then assign them to various roles. Simply add the new "category" to both lists:

    # Assign the access and edit permissions for issue, file and message
    # to regular users now
    for cl in 'issue', 'file', 'msg', 'category':
        p = db.security.getPermission('View', cl)
        db.security.addPermissionToRole('User', 'View', cl)
        db.security.addPermissionToRole('User', 'Edit', cl)
        db.security.addPermissionToRole('User', 'Create', cl)

These lines assign the "View" and "Edit" Permissions to the "User" role, so that normal users can view and edit "category" objects.

This is all the work that needs to be done for the database. It will store categories, and let users view and edit them. Now on to the interface stuff.

##### Changing the web left hand frame

We need to give the users the ability to create new categories, and the place to put the link to this functionality is in the left hand function bar, under the "Issues" area. The file that defines how this area looks is `html/page.html`, which is what we are going to be editing next.

If you look at this file you can see that it contains a lot of "classblock" sections which are chunks of HTML that will be included or excluded in the output depending on whether the condition in the classblock is met. We are going to add the category code at the end of the classblock for the issue class:

    <p class="classblock"
       tal:condition="python:request.user.hasPermission('View', 'category')">
     <b>Categories</b><br>
     <a tal:condition="python:request.user.hasPermission('Edit', 'category')"
        href="category?@template=item">New Category<br></a>
    </p>

The first two lines is the classblock definition, which sets up a condition that only users who have "View" permission for the "category" object will have this section included in their output. Next comes a plain "Categories" header in bold. Everyone who can view categories will get that.

Next comes the link to the editing area of categories. This link will only appear if the condition - that the user has "Edit" permissions for the "category" objects - is matched. If they do have permission then they will get a link to another page which will let the user add new categories.

Note that if you have permission to view but not to edit categories, then all you will see is a "Categories" header with nothing underneath it. This is obviously not very good interface design, but will do for now. I just claim that it is so I can add more links in this section later on. However, to fix the problem you could change the condition in the classblock statement, so that only users with "Edit" permission would see the "Categories" stuff.

##### Setting up a page to edit categories

We defined code in the previous section which let users with the appropriate permissions see a link to a page which would let them edit conditions. Now we have to write that page.

The link was for the item template of the category object. This translates into Roundup looking for a file called `category.item.html` in the `html` tracker directory. This is the file that we are going to write now.

First, we add an info tag in a comment which doesn't affect the outcome of the code at all, but is useful for debugging. If you load a page in a browser and look at the page source, you can see which sections come from which files by looking for these comments:

    <!-- category.item -->

Next we need to add in the METAL macro stuff so we get the normal page trappings:

    <tal:block metal:use-macro="templates/page/macros/icing">
     <title metal:fill-slot="head_title">Category editing</title>
     <td class="page-header-top" metal:fill-slot="body_title">
      <h2>Category editing</h2>
     </td>
     <td class="content" metal:fill-slot="content">

Next we need to setup up a standard HTML form, which is the whole purpose of this file. We link to some handy javascript which sends the form through only once. This is to stop users hitting the send button multiple times when they are impatient and thus having the form sent multiple times:

    <form method="POST" onSubmit="return submit_once()"
          enctype="multipart/form-data">

Next we define some code which sets up the minimum list of fields that we require the user to enter. There will be only one field - "name" - so they better put something in it, otherwise the whole form is pointless:

    <input type="hidden" name="@required" value="name">

To get everything to line up properly we will put everything in a table, and put a nice big header on it so the user has an idea what is happening:

    <table class="form">
     <tr><th class="header" colspan="2">Category</th></tr>

Next, we need the field into which the user is going to enter the new category. The `context.name.field(size=60)` bit tells Roundup to generate a normal HTML field of size 60, and the contents of that field will be the "name" variable of the current context (namely "category"). The upshot of this is that when the user types something in to the form, a new category will be created with that name:

    <tr>
     <th>Name</th>
     <td tal:content="structure python:context.name.field(size=60)">
     name</td>
    </tr>

Then a submit button so that the user can submit the new category:

    <tr>
     <td>&nbsp;</td>
     <td colspan="3" tal:content="structure context/submit">
      submit button will go here
     </td>
    </tr>

Finally we finish off the tags we used at the start to do the METAL stuff:

     </td>
    </tal:block>

So putting it all together, and closing the table and form we get:

    <!-- category.item -->
    <tal:block metal:use-macro="templates/page/macros/icing">
     <title metal:fill-slot="head_title">Category editing</title>
     <td class="page-header-top" metal:fill-slot="body_title">
      <h2>Category editing</h2>
     </td>
     <td class="content" metal:fill-slot="content">
      <form method="POST" onSubmit="return submit_once()"
            enctype="multipart/form-data">

       <table class="form">
        <tr><th class="header" colspan="2">Category</th></tr>

        <tr>
         <th>Name</th>
         <td tal:content="structure python:context.name.field(size=60)">
         name</td>
        </tr>

        <tr>
         <td>
           &nbsp;
           <input type="hidden" name="@required" value="name">
         </td>
         <td colspan="3" tal:content="structure context/submit">
          submit button will go here
         </td>
        </tr>
       </table>
      </form>
     </td>
    </tal:block>

This is quite a lot to just ask the user one simple question, but there is a lot of setup for basically one line (the form line) to do its work. To add another field to "category" would involve one more line (well, maybe a few extra to get the formatting correct).

##### Adding the category to the issue

We now have the ability to create issues to our heart's content, but that is pointless unless we can assign categories to issues. Just like the `html/category.item.html` file was used to define how to add a new category, the `html/issue.item.html` is used to define how a new issue is created.

Just like `category.issue.html`, this file defines a form which has a table to lay things out. It doesn't matter where in the table we add new stuff, it is entirely up to your sense of aesthetics:

    <th>Category</th>
    <td>
     <span tal:replace="structure context/category/field" />
     <span tal:replace="structure python:db.category.classhelp('name',
                 property='category', width='200')" />
    </td>

First, we define a nice header so that the user knows what the next section is, then the middle line does what we are most interested in. This `context/category/field` gets replaced by a field which contains the category in the current context (the current context being the new issue).

The classhelp lines generate a link (labelled "list") to a popup window which contains the list of currently known categories.

##### Searching on categories

Now we can add categories, and create issues with categories. The next obvious thing that we would like to be able to do, would be to search for issues based on their category, so that, for example, anyone working on the web server could look at all issues in the category "Web".

If you look for "Search Issues" in the `html/page.html` file, you will find that it looks something like `<a href="issue?@template=search">Search Issues</a>`. This shows us that when you click on "Search Issues" it will be looking for a `issue.search.html` file to display. So that is the file that we will change.

If you look at this file it should begin to seem familiar, although it does use some new macros. You can add the new category search code anywhere you like within that form:

    <tr tal:define="name string:category;
                    db_klass string:category;
                    db_content string:name;">
      <th>Priority:</th>
      <td metal:use-macro="search_select"></td>
      <td metal:use-macro="column_input"></td>
      <td metal:use-macro="sort_input"></td>
      <td metal:use-macro="group_input"></td>
    </tr>

The definitions in the `<tr>` opening tag are used by the macros:

- `search_select` expands to a drop-down box with all categories using `db_klass` and `db_content`.
- `column_input` expands to a checkbox for selecting what columns should be displayed.
- `sort_input` expands to a radio button for selecting what property should be sorted on.
- `group_input` expands to a radio button for selecting what property should be grouped on.

The category search code above would expand to the following:

    <tr>
      <th>Category:</th>
      <td>
        <select name="category">
          <option value="">don't care</option>
          <option value="">------------</option>
          <option value="1">scipy</option>
          <option value="2">chaco</option>
          <option value="3">weave</option>
        </select>
      </td>
      <td><input type="checkbox" name=":columns" value="category"></td>
      <td><input type="radio" name=":sort0" value="category"></td>
      <td><input type="radio" name=":group0" value="category"></td>
    </tr>

##### Adding category to the default view

We can now add categories, add issues with categories, and search for issues based on categories. This is everything that we need to do; however, there is some more icing that we would like. I think the category of an issue is important enough that it should be displayed by default when listing all the issues.

Unfortunately, this is a bit less obvious than the previous steps. The code defining how the issues look is in `html/issue.index.html`. This is a large table with a form down at the bottom for redisplaying and so forth.

Firstly we need to add an appropriate header to the start of the table:

    <th tal:condition="request/show/category">Category</th>

The condition part of this statement is to avoid displaying the Category column if the user has selected not to see it.

The rest of the table is a loop which will go through every issue that matches the display criteria. The loop variable is "i" - which means that every issue gets assigned to "i" in turn.

The new part of code to display the category will look like this:

    <td tal:condition="request/show/category"
        tal:content="i/category"></td>

The condition is the same as above: only display the condition when the user hasn't asked for it to be hidden. The next part is to set the content of the cell to be the category part of "i" - the current issue.

Finally we have to edit `html/page.html` again. This time, we need to tell it that when the user clicks on "Unassigned Issues" or "All Issues", the category column should be included in the resulting list. If you scroll down the page file, you can see the links with lots of options. The option that we are interested in is the `:columns=` one which tells roundup which fields of the issue to display. Simply add "category" to that list and it all should work.

#### Adding a time log to your issues

We want to log the dates and amount of time spent working on issues, and be able to give a summary of the total time spent on a particular issue.

1. Add a new class to your tracker `schema.py`:

       # storage for time logging
       timelog = Class(db, "timelog", period=Interval())

   Note that we automatically get the date of the time log entry creation through the standard property "creation".

   You will need to grant "Creation" permission to the users who are allowed to add timelog entries. You may do this with:

       db.security.addPermissionToRole('User', 'Create', 'timelog')
       db.security.addPermissionToRole('User', 'View', 'timelog')

   If users are also able to edit timelog entries, then also include:

       db.security.addPermissionToRole('User', 'Edit', 'timelog')

2. Link to the new class from your issue class (again, in `schema.py`):

       issue = IssueClass(db, "issue",
                       assignedto=Link("user"), keyword=Multilink("keyword"),
                       priority=Link("priority"), status=Link("status"),
                       times=Multilink("timelog"))

   the "times" property is the new link to the "timelog" class.

3. We'll need to let people add in times to the issue, so in the web interface we'll have a new entry field. This is a special field because unlike the other fields in the `issue.item` template, it affects a different item (a timelog item) and not the template's item (an issue). We have a special syntax for form fields that affect items other than the template default item (see the cgi documentation on special form variables). In particular, we add a field to capture a new timelog item's period:

       <tr>
        <th>Time Log</th>
        <td colspan=3><input type="text" name="timelog-1@period" />
         (enter as '3y 1m 4d 2:40:02' or parts thereof)
        </td>
       </tr>

   and another hidden field that links that new timelog item (new because it's marked as having id "-1") to the issue item. It looks like this:

       <input type="hidden" name="@link@times" value="timelog-1" />

   On submission, the "-1" timelog item will be created and assigned a real item id. The "times" property of the issue will have the new id added to it.

   The full entry will now look like this:

       <tr>
        <th>Time Log</th>
        <td colspan=3><input type="text" name="timelog-1@period" />
         (enter as '3y 1m 4d 2:40:02' or parts thereof)
         <input type="hidden" name="@link@times" value="timelog-1" />
        </td>
       </tr>

4. We want to display a total of the timelog times that have been accumulated for an issue. To do this, we'll need to actually write some Python code, since it's beyond the scope of PageTemplates to perform such calculations. We do this by adding a module `timespent.py` to the `extensions` directory in our tracker. The contents of this file is as follows:

       from roundup import date

       def totalTimeSpent(times):
           ''' Call me with a list of timelog items (which have an
               Interval "period" property)
           '''
           total = date.Interval('0d')
           for time in times:
               total += time.period._value
           return total

       def init(instance):
           instance.registerUtil('totalTimeSpent', totalTimeSpent)

   We will now be able to access the `totalTimeSpent` function via the `utils` variable in our templates, as shown in the next step.

5. Display the timelog for an issue:

       <table class="otherinfo" tal:condition="context/times">
        <tr><th colspan="3" class="header">Time Log
         <tal:block
              tal:replace="python:utils.totalTimeSpent(context.times)" />
        </th></tr>
        <tr><th>Date</th><th>Period</th><th>Logged By</th></tr>
        <tr tal:repeat="time context/times">
         <td tal:content="time/creation"></td>
         <td tal:content="time/period"></td>
         <td tal:content="time/creator"></td>
        </tr>
       </table>

   I put this just above the Messages log in my issue display. Note our use of the `totalTimeSpent` method which will total up the times for the issue and return a new Interval. That will be automatically displayed in the template as text like "+ 1y 2:40" (1 year, 2 hours and 40 minutes).

6. If you're using a persistent web server - `roundup-server` or `mod_python` for example - then you'll need to restart that to pick up the code changes. When that's done, you'll be able to use the new time logging interface.

An extension of this modification attaches the timelog entries to any change message entered at the time of the timelog entry:

1. Add a link to the timelog to the msg class in `schema.py`:

   > msg = FileClass(db, "msg",

   >   author=Link("user", do_journal='no'), recipients=Multilink("user", do_journal='no'), date=Date(), summary=String(), files=Multilink("file"), messageid=String(), inreplyto=String(), times=Multilink("timelog"))

2. Add a new hidden field that links that new timelog item (new because it's marked as having id "-1") to the new message. The link is placed in `issue.item.html` in the same section that handles the timelog entry.

   It looks like this after this addition:

       <tr>
        <th>Time Log</th>
        <td colspan=3><input type="text" name="timelog-1@period" />
         (enter as '3y 1m 4d 2:40:02' or parts thereof)
         <input type="hidden" name="@link@times" value="timelog-1" />
         <input type="hidden" name="msg-1@link@times" value="timelog-1" />
        </td>
       </tr>

   The "times" property of the message will have the new id added to it.

3. Add the timelog listing from step 5. to the `msg.item.html` template so that the timelog entry appears on the message view page. Note that the call to totalTimeSpent is not used here since there will only be one single timelog entry for each message.

   I placed it after the Date entry like this:

       <tr>
        <th i18n:translate="">Date:</th>
        <td tal:content="context/date"></td>
       </tr>
       </table>

       <table class="otherinfo" tal:condition="context/times">
        <tr><th colspan="3" class="header">Time Log</th></tr>
        <tr><th>Date</th><th>Period</th><th>Logged By</th></tr>
        <tr tal:repeat="time context/times">
         <td tal:content="time/creation"></td>
         <td tal:content="time/period"></td>
         <td tal:content="time/creator"></td>
        </tr>
       </table>

       <table class="messages">

#### Tracking different types of issues

Sometimes you will want to track different types of issues - developer, customer support, systems, sales leads, etc. A single Roundup tracker is able to support multiple types of issues. This example demonstrates adding a system support issue class to a tracker.

1. Figure out what information you're going to want to capture. OK, so this is obvious, but sometimes it's better to actually sit down for a while and think about the schema you're going to implement.

2. Add the new issue class to your tracker's `schema.py`. Just after the "issue" class definition, add:

       # list our systems
       system = Class(db, "system", name=String(), order=Number())
       system.setkey("name")

       # store issues related to those systems
       support = IssueClass(db, "support",
                       assignedto=Link("user"), keyword=Multilink("keyword"),
                       status=Link("status"), deadline=Date(),
                       affects=Multilink("system"))

3. Copy the existing `issue.*` (item, search and index) templates in the tracker's `html` to `support.*`. Edit them so they use the properties defined in the `support` class. Be sure to check for hidden form variables like "required" to make sure they have the correct set of required properties.

4. Edit the modules in the `detectors`, adding lines to their `init` functions where appropriate. Look for `audit` and `react` registrations on the `issue` class, and duplicate them for `support`.

5. Create a new sidebar box for the new support class. Duplicate the existing issues one, changing the `issue` class name to `support`.

6. Re-start your tracker and start using the new `support` class.

Optionally, you might want to restrict the users able to access this new class to just the users with a new "SysAdmin" Role. To do this, we add some security declarations:

    db.security.addPermissionToRole('SysAdmin', 'View', 'support')
    db.security.addPermissionToRole('SysAdmin', 'Create', 'support')
    db.security.addPermissionToRole('SysAdmin', 'Edit', 'support')

You would then (as an "admin" user) edit the details of the appropriate users, and add "SysAdmin" to their Roles list.

Alternatively, you might want to change the Edit/View permissions granted for the `issue` class so that it's only available to users with the "System" or "Developer" Role, and then the new class you're adding is available to all with the "User" Role.

### Using External User Databases

#### Using an external password validation source

Note

You will need to either have an "admin" user in your external password source or have one of your regular users have the Admin Role assigned. If you need to assign the Role after making the changes below, you may use the `roundup-admin` program to edit a user's details.

We have a centrally-managed password changing system for our users. This results in a UN*X passwd-style file that we use for verification of users. Entries in the file consist of `name:password` where the password is encrypted using the standard UN*X `crypt()` function (see the `crypt` module in your Python distribution). An example entry would be:

    admin:aamrgyQfDFSHw

Each user of Roundup must still have their information stored in the Roundup database - we just use the passwd file to check their password. To do this, we need to override the standard `verifyPassword` method defined in `roundup.cgi.actions.LoginAction` and register the new class. The following is added as `externalpassword.py` in the tracker `extensions` directory:

    import os, crypt
    from roundup.cgi.actions import LoginAction

    class ExternalPasswordLoginAction(LoginAction):
        def verifyPassword(self, userid, password):
            '''Look through the file, line by line, looking for a
            name that matches.
            '''
            # get the user's username
            username = self.db.user.get(userid, 'username')

            # the passwords are stored in the "passwd.txt" file in the
            # tracker home
            file = os.path.join(self.db.config.TRACKER_HOME, 'passwd.txt')

            # see if we can find a match
            for ent in [line.strip().split(':') for line in
                                                open(file).readlines()]:
                if ent[0] == username:
                    return crypt.crypt(password, ent[1][:2]) == ent[1]

            # user doesn't exist in the file
            return 0

    def init(instance):
        instance.registerAction('login', ExternalPasswordLoginAction)

You should also remove the redundant password fields from the `user.item` template.

#### Using a UN*X passwd file as the user database

On some systems the primary store of users is the UN*X passwd file. It holds information on users such as their username, real name, password and primary user group.

Roundup can use this store as its primary source of user information, but it needs additional information too - email address(es), roundup Roles, vacation flags, roundup hyperdb item ids, etc. Also, "retired" users must still exist in the user database, unlike some passwd files in which the users are removed when they no longer have access to a system.

To make use of the passwd file, we therefore synchronise between the two user stores. We also use the passwd file to validate the user logins, as described in the previous example, using an external password validation source. We keep the user lists in sync using a fairly simple script that runs once a day, or several times an hour if more immediate access is needed. In short, it:

1. parses the passwd file, finding usernames, passwords and real names,
2. compares that list to the current roundup user list:
   1. entries no longer in the passwd file are retired
   2. entries with mismatching real names are updated
   3. entries only exist in the passwd file are created
3. send an email to administrators to let them know what's been done.

The retiring and updating are simple operations, requiring only a call to `retire()` or `set()`. The creation operation requires more information though - the user's email address and their Roundup Roles. We're going to assume that the user's email address is the same as their login name, so we just append the domain name to that. The Roles are determined using the passwd group identifier - mapping their UN*X group to an appropriate set of Roles.

The script to perform all this, broken up into its main components, is as follows. Firstly, we import the necessary modules and open the tracker we're to work on:

    import sys, os, smtplib
    from roundup import instance, date

    # open the tracker
    tracker_home = sys.argv[1]
    tracker = instance.open(tracker_home)

Next we read in the passwd file from the tracker home:

    # read in the users from the "passwd.txt" file
    file = os.path.join(tracker_home, 'passwd.txt')
    users = [x.strip().split(':') for x in open(file).readlines()]

Handle special users (those to ignore in the file, and those who don't appear in the file):

    # users to not keep ever, pre-load with the users I know aren't
    # "real" users
    ignore = ['ekmmon', 'bfast', 'csrmail']

    # users to keep - pre-load with the roundup-specific users
    keep = ['comment_pool', 'network_pool', 'admin', 'dev-team',
            'cs_pool', 'anonymous', 'system_pool', 'automated']

Now we map the UN*X group numbers to the Roles that users should have:

    roles = {
     '501': 'User,Tech',  # tech
     '502': 'User',       # finance
     '503': 'User,CSR',   # customer service reps
     '504': 'User',       # sales
     '505': 'User',       # marketing
    }

Now we do all the work. Note that the body of the script (where we have the tracker database open) is wrapped in a `try` / `finally` clause, so that we always close the database cleanly when we're finished. So, we now do all the work:

    # open the database
    db = tracker.open('admin')
    try:
        # store away messages to send to the tracker admins
        msg = []

        # loop over the users list read in from the passwd file
        for user,passw,uid,gid,real,home,shell in users:
            if user in ignore:
                # this user shouldn't appear in our tracker
                continue
            keep.append(user)
            try:
                # see if the user exists in the tracker
                uid = db.user.lookup(user)

                # yes, they do - now check the real name for correctness
                if real != db.user.get(uid, 'realname'):
                    db.user.set(uid, realname=real)
                    msg.append('FIX %s - %s'%(user, real))
            except KeyError:
                # nope, the user doesn't exist
                db.user.create(username=user, realname=real,
                    address='%s@ekit-inc.com'%user, roles=roles[gid])
                msg.append('ADD %s - %s (%s)'%(user, real, roles[gid]))

        # now check that all the users in the tracker are also in our
        # "keep" list - retire those who aren't
        for uid in db.user.list():
            user = db.user.get(uid, 'username')
            if user not in keep:
                db.user.retire(uid)
                msg.append('RET %s'%user)

        # if we did work, then send email to the tracker admins
        if msg:
            # create the email
            msg = '''Subject: %s user database maintenance

            %s
            '''%(db.config.TRACKER_NAME, '\n'.join(msg))

            # send the email
            smtp = smtplib.SMTP(db.config.MAILHOST)
            addr = db.config.ADMIN_EMAIL
            smtp.sendmail(addr, addr, msg)

        # now we're done - commit the changes
        db.commit()
    finally:
        # always close the database cleanly
        db.close()

And that's it!

#### Using an LDAP database for user information

A script that reads users from an LDAP store using http://python-ldap.sf.net/ and then compares the list to the users in the roundup user database would be pretty easy to write. You'd then have it run once an hour / day (or on demand if you can work that into your LDAP store workflow). See the example Using a UN*X passwd file as the user database for more information about doing this.

To authenticate off the LDAP store (rather than using the passwords in the Roundup user database) you'd use the same python-ldap module inside an extension to the cgi interface. You'd do this by overriding the method called `verifyPassword` on the `LoginAction` class in your tracker's `extensions` directory (see using an external password validation source). The method is implemented by default as:

    def verifyPassword(self, userid, password):
        ''' Verify the password that the user has supplied
        '''
        stored = self.db.user.get(self.userid, 'password')
        if password == stored:
            return 1
        if not password and not stored:
            return 1
        return 0

So you could reimplement this as something like:

    def verifyPassword(self, userid, password):
        ''' Verify the password that the user has supplied
        '''
        # look up some unique LDAP information about the user
        username = self.db.user.get(self.userid, 'username')
        # now verify the password supplied against the LDAP store

### Changes to Tracker Behaviour

#### Preventing SPAM

The following detector code may be installed in your tracker's `detectors` directory. It will block any messages being created that have HTML attachments (a very common vector for spam and phishing) and any messages that have more than 2 HTTP URLs in them. Just copy the following into `detectors/anti_spam.py` in your tracker:

    from roundup.exceptions import Reject

    def reject_html(db, cl, nodeid, newvalues):
        if newvalues['type'] == 'text/html':
        raise Reject, 'not allowed'

    def reject_manylinks(db, cl, nodeid, newvalues):
        content = newvalues['content']
        if content.count('http://') > 2:
        raise Reject, 'not allowed'

    def init(db):
        db.file.audit('create', reject_html)
        db.msg.audit('create', reject_manylinks)

You may also wish to block image attachments if your tracker does not need that ability:

    if newvalues['type'].startswith('image/'):
        raise Reject, 'not allowed'

#### Stop "nosy" messages going to people on vacation

When users go on vacation and set up vacation email bouncing, you'll start to see a lot of messages come back through Roundup "Fred is on vacation". Not very useful, and relatively easy to stop.

1. add a "vacation" flag to your users:

       user = Class(db, "user",
                  username=String(),   password=Password(),
                  address=String(),    realname=String(),
                  phone=String(),      organisation=String(),
                  alternate_addresses=String(),
                  roles=String(), queries=Multilink("query"),
                  vacation=Boolean())

2. So that users may edit the vacation flags, add something like the following to your `user.item` template:

       <tr>
        <th>On Vacation</th>
        <td tal:content="structure context/vacation/field">vacation</td>
       </tr>

3. edit your detector `nosyreactor.py` so that the `nosyreaction()` consists of:

       def nosyreaction(db, cl, nodeid, oldvalues):
           users = db.user
           messages = db.msg
           # send a copy of all new messages to the nosy list
           for msgid in determineNewMessages(cl, nodeid, oldvalues):
               try:
                   # figure the recipient ids
                   sendto = []
                   seen_message = {}
                   recipients = messages.get(msgid, 'recipients')
                   for recipid in messages.get(msgid, 'recipients'):
                       seen_message[recipid] = 1

                   # figure the author's id, and indicate they've received
                   # the message
                   authid = messages.get(msgid, 'author')

                   # possibly send the message to the author, as long as
                   # they aren't anonymous
                   if (db.config.MESSAGES_TO_AUTHOR == 'yes' and
                           users.get(authid, 'username') != 'anonymous'):
                       sendto.append(authid)
                   seen_message[authid] = 1

                   # now figure the nosy people who weren't recipients
                   nosy = cl.get(nodeid, 'nosy')
                   for nosyid in nosy:
                       # Don't send nosy mail to the anonymous user (that
                       # user shouldn't appear in the nosy list, but just
                       # in case they do...)
                       if users.get(nosyid, 'username') == 'anonymous':
                           continue
                       # make sure they haven't seen the message already
                       if not seen_message.has_key(nosyid):
                           # send it to them
                           sendto.append(nosyid)
                           recipients.append(nosyid)

                   # generate a change note
                   if oldvalues:
                       note = cl.generateChangeNote(nodeid, oldvalues)
                   else:
                       note = cl.generateCreateNote(nodeid)

                   # we have new recipients
                   if sendto:
                       # filter out the people on vacation
                       sendto = [i for i in sendto
                                 if not users.get(i, 'vacation', 0)]

                       # map userids to addresses
                       sendto = [users.get(i, 'address') for i in sendto]

                       # update the message's recipients list
                       messages.set(msgid, recipients=recipients)

                       # send the message
                       cl.send_message(nodeid, msgid, note, sendto)
               except roundupdb.MessageSendError, message:
                   raise roundupdb.DetectorError, message

   Note that this is the standard nosy reaction code, with the small addition of:

       # filter out the people on vacation
       sendto = [i for i in sendto if not users.get(i, 'vacation', 0)]

   which filters out the users that have the vacation flag set to true.

#### Adding in state transition control

Sometimes tracker admins want to control the states to which users may move issues. You can do this by following these steps:

1. make "status" a required variable. This is achieved by adding the following to the top of the form in the `issue.item.html` template:

       <input type="hidden" name="@required" value="status">

   This will force users to select a status.

2. add a Multilink property to the status class:

       stat = Class(db, "status", ... , transitions=Multilink('status'),
                    ...)

   and then edit the statuses already created, either:

   1. through the web using the class list -> status class editor, or
   2. using the `roundup-admin` "set" command.

3. add an auditor module `checktransition.py` in your tracker's `detectors` directory, for example:

       def checktransition(db, cl, nodeid, newvalues):
           ''' Check that the desired transition is valid for the "status"
               property.
           '''
           if not newvalues.has_key('status'):
               return
           current = cl.get(nodeid, 'status')
           new = newvalues['status']
           if new == current:
               return
           ok = db.status.get(current, 'transitions')
           if new not in ok:
               raise ValueError, 'Status not allowed to move from "%s" to "%s"'%(
                   db.status.get(current, 'name'), db.status.get(new, 'name'))

       def init(db):
           db.issue.audit('set', checktransition)

4. in the `issue.item.html` template, change the status editing bit from:

       <th>Status</th>
       <td tal:content="structure context/status/menu">status</td>

   to:

       <th>Status</th>
       <td>
        <select tal:condition="context/id" name="status">
         <tal:block tal:define="ok context/status/transitions"
                    tal:repeat="state db/status/list">
          <option tal:condition="python:state.id in ok"
                  tal:attributes="
                       value state/id;
                       selected python:state.id == context.status.id"
                  tal:content="state/name"></option>
         </tal:block>
        </select>
        <tal:block tal:condition="not:context/id"
                   tal:replace="structure context/status/menu" />
       </td>

   which displays only the allowed status to transition to.

#### Blocking issues that depend on other issues

We needed the ability to mark certain issues as "blockers" - that is, they can't be resolved until another issue (the blocker) they rely on is resolved. To achieve this:

1. Create a new property on the `issue` class: `blockers=Multilink("issue")`. To do this, edit the definition of this class in your tracker's `schema.py` file. Change this:

       issue = IssueClass(db, "issue",
                       assignedto=Link("user"), keyword=Multilink("keyword"),
                       priority=Link("priority"), status=Link("status"))

   to this, adding the blockers entry:

       issue = IssueClass(db, "issue",
                       blockers=Multilink("issue"),
                       assignedto=Link("user"), keyword=Multilink("keyword"),
                       priority=Link("priority"), status=Link("status"))

2. Add the new `blockers` property to the `issue.item.html` edit page, using something like:

       <th>Waiting On</th>
       <td>
        <span tal:replace="structure python:context.blockers.field(showid=1,
                                     size=20)" />
        <span tal:replace="structure python:db.issue.classhelp('id,title',
                                     property='blockers')" />
        <span tal:condition="context/blockers"
              tal:repeat="blk context/blockers">
         <br>View: <a tal:attributes="href string:issue${blk/id}"
                      tal:content="blk/id"></a>
        </span>
       </td>

   You'll need to fiddle with your item page layout to find an appropriate place to put it - I'll leave that fun part up to you. Just make sure it appears in the first table, possibly somewhere near the "superseders" field.

3. Create a new detector module (see below) which enforces the rules:

   - issues may not be resolved if they have blockers
   - when a blocker is resolved, it's removed from issues it blocks

   The contents of the detector should be something like this:

       def blockresolution(db, cl, nodeid, newvalues):
           ''' If the issue has blockers, don't allow it to be resolved.
           '''
           if nodeid is None:
               blockers = []
           else:
               blockers = cl.get(nodeid, 'blockers')
           blockers = newvalues.get('blockers', blockers)

           # don't do anything if there's no blockers or the status hasn't
           # changed
           if not blockers or not newvalues.has_key('status'):
               return

           # get the resolved state ID
           resolved_id = db.status.lookup('resolved')

           # format the info
           u = db.config.TRACKER_WEB
           s = ', '.join(['<a href="%sissue%s">%s</a>'%(
                           u,id,id) for id in blockers])
           if len(blockers) == 1:
               s = 'issue %s is'%s
           else:
               s = 'issues %s are'%s

           # ok, see if we're trying to resolve
           if newvalues['status'] == resolved_id:
               raise ValueError, "This issue can't be resolved until %s resolved."%s

       def resolveblockers(db, cl, nodeid, oldvalues):
           ''' When we resolve an issue that's a blocker, remove it from the
               blockers list of the issue(s) it blocks.
           '''
           newstatus = cl.get(nodeid,'status')

           # no change?
           if oldvalues.get('status', None) == newstatus:
               return

           resolved_id = db.status.lookup('resolved')

           # interesting?
           if newstatus != resolved_id:
               return

           # yes - find all the blocked issues, if any, and remove me from
           # their blockers list
           issues = cl.find(blockers=nodeid)
           for issueid in issues:
               blockers = cl.get(issueid, 'blockers')
               if nodeid in blockers:
                   blockers.remove(nodeid)
                   cl.set(issueid, blockers=blockers)

       def init(db):
           # might, in an obscure situation, happen in a create
           db.issue.audit('create', blockresolution)
           db.issue.audit('set', blockresolution)

           # can only happen on a set
           db.issue.react('set', resolveblockers)

   Put the above code in a file called "blockers.py" in your tracker's "detectors" directory.

4. Finally, and this is an optional step, modify the tracker web page URLs so they filter out issues with any blockers. You do this by adding an additional filter on "blockers" for the value "-1". For example, the existing "Show All" link in the "page" template (in the tracker's "html" directory) looks like this:

       <a href="#"
          tal:attributes="href python:request.indexargs_url('issue', {
         '@sort': '-activity',
         '@group': 'priority',
         '@filter': 'status',
         '@columns': columns_showall,
         '@search_text': '',
         'status': status_notresolved,
         '@dispname': i18n.gettext('Show All'),
        })"
          i18n:translate="">Show All</a><br>

   modify it to add the "blockers" info to the URL (note, both the "@filter" and "blockers" values must be specified):

       <a href="#"
          tal:attributes="href python:request.indexargs_url('issue', {
         '@sort': '-activity',
         '@group': 'priority',
         '@filter': 'status,blockers',
         '@columns': columns_showall,
         '@search_text': '',
         'status': status_notresolved,
         'blockers': '-1',
         '@dispname': i18n.gettext('Show All'),
        })"
          i18n:translate="">Show All</a><br>

   The above examples are line-wrapped on the trailing & and should be unwrapped.

That's it. You should now be able to set blockers on your issues. Note that if you want to know whether an issue has any other issues dependent on it (i.e. it's in their blockers list) you can look at the journal history at the bottom of the issue page - look for a "link" event to another issue's "blockers" property.

#### Add users to the nosy list based on the keyword

Let's say we need the ability to automatically add users to the nosy list based on the occurance of a keyword. Every user should be allowed to edit their own list of keywords for which they want to be added to the nosy list.

Below, we'll show that this change can be done with minimal understanding of the Roundup system, using only copy and paste.

This requires three changes to the tracker: a change in the database to allow per-user recording of the lists of keywords for which he wants to be put on the nosy list, a change in the user view allowing them to edit this list of keywords, and addition of an auditor which updates the nosy list when a keyword is set.

##### Adding the nosy keyword list

The change to make in the database, is that for any user there should be a list of keywords for which he wants to be put on the nosy list. Adding a `Multilink` of `keyword` seems to fullfill this. As such, all that has to be done is to add a new field to the definition of `user` within the file `schema.py`. We will call this new field `nosy_keywords`, and the updated definition of user will be:

    user = Class(db, "user",
                    username=String(),   password=Password(),
                    address=String(),    realname=String(),
                    phone=String(),      organisation=String(),
                    alternate_addresses=String(),
                    queries=Multilink('query'), roles=String(),
                    timezone=String(),
                    nosy_keywords=Multilink('keyword'))

##### Changing the user view to allow changing the nosy keyword list

We want any user to be able to change the list of keywords for which he will by default be added to the nosy list. We choose to add this to the user view, as is generated by the file `html/user.item.html`. We can easily see that the keyword field in the issue view has very similar editing requirements as our nosy keywords, both being lists of keywords. As such, we look for Keywords in `issue.item.html`, and extract the associated parts from there. We add this to `user.item.html` at the bottom of the list of viewed items (i.e. just below the 'Alternate E-mail addresses' in the classic template):

    <tr>
     <th>Nosy Keywords</th>
     <td>
     <span tal:replace="structure context/nosy_keywords/field" />
     <span tal:replace="structure python:db.keyword.classhelp(property='nosy_keywords')" />
     </td>
    </tr>

##### Addition of an auditor to update the nosy list

The more difficult part is the logic to add the users to the nosy list when required. We choose to perform this action whenever the keywords on an item are set (this includes the creation of items). Here we choose to start out with a copy of the `detectors/nosyreaction.py` detector, which we copy to the file `detectors/nosy_keyword_reaction.py`. This looks like a good start as it also adds users to the nosy list. A look through the code reveals that the `nosyreaction` function actually sends the e-mail. We don't need this. Therefore, we can change the `init` function to:

    def init(db):
        db.issue.audit('create', update_kw_nosy)
        db.issue.audit('set', update_kw_nosy)

After that, we rename the `updatenosy` function to `update_kw_nosy`. The first two blocks of code in that function relate to setting `current` to a combination of the old and new nosy lists. This functionality is left in the new auditor. The following block of code, which handled adding the assignedto user(s) to the nosy list in `updatenosy`, should be replaced by a block of code to add the interested users to the nosy list. We choose here to loop over all new keywords, than looping over all users, and assign the user to the nosy list when the keyword occurs in the user's `nosy_keywords`. The next part in `updatenosy` -- adding the author and/or recipients of a message to the nosy list -- is obviously not relevant here and is thus deleted from the new auditor. The last part, copying the new nosy list to `newvalues`, can stay as is. This results in the following function:

    def update_kw_nosy(db, cl, nodeid, newvalues):
        '''Update the nosy list for changes to the keywords
        '''
        # nodeid will be None if this is a new node
        current = {}
        if nodeid is None:
            ok = ('new', 'yes')
        else:
            ok = ('yes',)
            # old node, get the current values from the node if they haven't
            # changed
            if not newvalues.has_key('nosy'):
                nosy = cl.get(nodeid, 'nosy')
                for value in nosy:
                    if not current.has_key(value):
                        current[value] = 1

        # if the nosy list changed in this transaction, init from the new value
        if newvalues.has_key('nosy'):
            nosy = newvalues.get('nosy', [])
            for value in nosy:
                if not db.hasnode('user', value):
                    continue
                if not current.has_key(value):
                    current[value] = 1

        # add users with keyword in nosy_keywords to the nosy list
        if newvalues.has_key('keyword') and newvalues['keyword'] is not None:
            keyword_ids = newvalues['keyword']
            for keyword in keyword_ids:
                # loop over all users,
                # and assign user to nosy when keyword in nosy_keywords
                for user_id in db.user.list():
                    nosy_kw = db.user.get(user_id, "nosy_keywords")
                    found = 0
                    for kw in nosy_kw:
                        if kw == keyword:
                            found = 1
                    if found:
                        current[user_id] = 1

        # that's it, save off the new nosy list
        newvalues['nosy'] = current.keys()

These two function are the only ones needed in the file.

TODO: update this example to use the `find()` Class method.

##### Caveats

A few problems with the design here can be noted:

Multiple additions

  When a user, after automatic selection, is manually removed from the nosy list, he is added to the nosy list again when the keyword list of the issue is updated. A better design might be to only check which keywords are new compared to the old list of keywords, and only add users when they have indicated interest on a new keyword.

  The code could also be changed to only trigger on the `create()` event, rather than also on the `set()` event, thus only setting the nosy list when the issue is created.

Scalability
  In the auditor, there is a loop over all users. For a site with only few users this will pose no serious problem; however, with many users this will be a serious performance bottleneck. A way out would be to link from the keywords to the users who selected these keywords as nosy keywords. This will eliminate the loop over all users.

### Changes to Security and Permissions

#### Restricting the list of users that are assignable to a task

1. In your tracker's `schema.py`, create a new Role, say "Developer":

       db.security.addRole(name='Developer', description='A developer')

2. Just after that, create a new Permission, say "Fixer", specific to "issue":

       p = db.security.addPermission(name='Fixer', klass='issue',
           description='User is allowed to be assigned to fix issues')

3. Then assign the new Permission to your "Developer" Role:

       db.security.addPermissionToRole('Developer', p)

4. In the issue item edit page (`html/issue.item.html` in your tracker directory), use the new Permission in restricting the "assignedto" list:

       <select name="assignedto">
        <option value="-1">- no selection -</option>
        <tal:block tal:repeat="user db/user/list">
        <option tal:condition="python:user.hasPermission(
                                   'Fixer', context._classname)"
                tal:attributes="
                   value user/id;
                   selected python:user.id == context.assignedto"
                tal:content="user/realname"></option>
        </tal:block>
       </select>

For extra security, you may wish to setup an auditor to enforce the Permission requirement (install this as `assignedtoFixer.py` in your tracker `detectors` directory):

    def assignedtoMustBeFixer(db, cl, nodeid, newvalues):
        ''' Ensure the assignedto value in newvalues is used with the
            Fixer Permission
        '''
        if not newvalues.has_key('assignedto'):
            # don't care
            return

        # get the userid
        userid = newvalues['assignedto']
        if not db.security.hasPermission('Fixer', userid, cl.classname):
            raise ValueError, 'You do not have permission to edit %s'%cl.classname

    def init(db):
        db.issue.audit('set', assignedtoMustBeFixer)
        db.issue.audit('create', assignedtoMustBeFixer)

So now, if an edit action attempts to set "assignedto" to a user that doesn't have the "Fixer" Permission, the error will be raised.

#### Users may only edit their issues

In this case, users registering themselves are granted Provisional access, meaning they have access to edit the issues they submit, but not others. We create a new Role called "Provisional User" which is granted to newly-registered users, and has limited access. One of the Permissions they have is the new "Edit Own" on issues (regular users have "Edit".)

First up, we create the new Role and Permission structure in `schema.py`:

    #
    # New users not approved by the admin
    #
    db.security.addRole(name='Provisional User',
        description='New user registered via web or email')

    # These users need to be able to view and create issues but only edit
    # and view their own
    db.security.addPermissionToRole('Provisional User', 'Create', 'issue')
    def own_issue(db, userid, itemid):
        '''Determine whether the userid matches the creator of the issue.'''
        return userid == db.issue.get(itemid, 'creator')
    p = db.security.addPermission(name='Edit', klass='issue',
        check=own_issue, description='Can only edit own issues')
    db.security.addPermissionToRole('Provisional User', p)
    p = db.security.addPermission(name='View', klass='issue',
        check=own_issue, description='Can only view own issues')
    db.security.addPermissionToRole('Provisional User', p)

    # Assign the Permissions for issue-related classes
    for cl in 'file', 'msg', 'query', 'keyword':
        db.security.addPermissionToRole('Provisional User', 'View', cl)
        db.security.addPermissionToRole('Provisional User', 'Edit', cl)
        db.security.addPermissionToRole('Provisional User', 'Create', cl)
    for cl in 'priority', 'status':
        db.security.addPermissionToRole('Provisional User', 'View', cl)

    # and give the new users access to the web and email interface
    db.security.addPermissionToRole('Provisional User', 'Web Access')
    db.security.addPermissionToRole('Provisional User', 'Email Access')

    # make sure they can view & edit their own user record
    def own_record(db, userid, itemid):
        '''Determine whether the userid matches the item being accessed.'''
        return userid == itemid
    p = db.security.addPermission(name='View', klass='user', check=own_record,
        description="User is allowed to view their own user details")
    db.security.addPermissionToRole('Provisional User', p)
    p = db.security.addPermission(name='Edit', klass='user', check=own_record,
        description="User is allowed to edit their own user details")
    db.security.addPermissionToRole('Provisional User', p)

Then, in `config.ini`, we change the Role assigned to newly-registered users, replacing the existing `'User'` values:

    [main]
    ...
    new_web_user_roles = 'Provisional User'
    new_email_user_roles = 'Provisional User'

#### All users may only view and edit issues, files and messages they create

Replace the standard "classic" tracker View and Edit Permission assignments for the "issue", "file" and "msg" classes with the following:

    def checker(klass):
        def check(db, userid, itemid, klass=klass):
            return db.getclass(klass).get(itemid, 'creator') == userid
        return check
    for cl in 'issue', 'file', 'msg':
        p = db.security.addPermission(name='View', klass=cl,
            check=checker(cl))
        db.security.addPermissionToRole('User', p)
        p = db.security.addPermission(name='Edit', klass=cl,
            check=checker(cl))
        db.security.addPermissionToRole('User', p)
        db.security.addPermissionToRole('User', 'Create', cl)

### Changes to the Web User Interface

#### Adding action links to the index page

Add a column to the `item.index.html` template.

Resolving the issue:

    <a tal:attributes="href
       string:issue${i/id}?:status=resolved&:action=edit">resolve</a>

"Take" the issue:

    <a tal:attributes="href
       string:issue${i/id}?:assignedto=${request/user/id}&:action=edit">take</a>

... and so on.

#### Colouring the rows in the issue index according to priority

A simple `tal:attributes` statement will do the bulk of the work here. In the `issue.index.html` template, add this to the `<tr>` that displays the rows of data:

    <tr tal:attributes="class string:priority-${i/priority/plain}">

and then in your stylesheet (`style.css`) specify the colouring for the different priorities, as follows:

    tr.priority-critical td {
        background-color: red;
    }

    tr.priority-urgent td {
        background-color: orange;
    }

and so on, with far less offensive colours :)

#### Editing multiple items in an index view

To edit the status of all items in the item index view, edit the `issue.item.html`:

1. add a form around the listing table (separate from the existing index-page form), so at the top it reads:

       <form method="POST" tal:attributes="action request/classname">
        <table class="list">

   and at the bottom of that table:

        </table>
       </form

   making sure you match the `</table>` from the list table, not the navigation table or the subsequent form table.

2. in the display for the issue property, change:

       <td tal:condition="request/show/status"
           tal:content="python:i.status.plain() or default">&nbsp;</td>

   to:

       <td tal:condition="request/show/status"
           tal:content="structure i/status/field">&nbsp;</td>

   this will result in an edit field for the status property.

3. after the `tal:block` which lists the index items (marked by `tal:repeat="i batch"`) add a new table row:

       <tr>
        <td tal:attributes="colspan python:len(request.columns)">
         <input type="submit" value=" Save Changes ">
         <input type="hidden" name="@action" value="edit">
         <tal:block replace="structure request/indexargs_form" />
        </td>
       </tr>

   which gives us a submit button, indicates that we are performing an edit on any changed statuses. The final `tal:block` will make sure that the current index view parameters (filtering, columns, etc) will be used in rendering the next page (the results of the editing).

#### Displaying only message summaries in the issue display

Alter the `issue.item` template section for messages to:

    <table class="messages" tal:condition="context/messages">
     <tr><th colspan="5" class="header">Messages</th></tr>
     <tr tal:repeat="msg context/messages">
      <td><a tal:attributes="href string:msg${msg/id}"
             tal:content="string:msg${msg/id}"></a></td>
      <td tal:content="msg/author">author</td>
      <td class="date" tal:content="msg/date/pretty">date</td>
      <td tal:content="msg/summary">summary</td>
      <td>
       <a tal:attributes="href string:?@remove@messages=${msg/id}&@action=edit">
       remove</a>
      </td>
     </tr>
    </table>

#### Enabling display of either message summaries or the entire messages

This is pretty simple - all we need to do is copy the code from the example displaying only message summaries in the issue display into our template alongside the summary display, and then introduce a switch that shows either the one or the other. We'll use a new form variable, `@whole_messages` to achieve this:

    <table class="messages" tal:condition="context/messages">
     <tal:block tal:condition="not:request/form/@whole_messages/value | python:0">
      <tr><th colspan="3" class="header">Messages</th>
          <th colspan="2" class="header">
            <a href="?@whole_messages=yes">show entire messages</a>
          </th>
      </tr>
      <tr tal:repeat="msg context/messages">
       <td><a tal:attributes="href string:msg${msg/id}"
              tal:content="string:msg${msg/id}"></a></td>
       <td tal:content="msg/author">author</td>
       <td class="date" tal:content="msg/date/pretty">date</td>
       <td tal:content="msg/summary">summary</td>
       <td>
        <a tal:attributes="href string:?@remove@messages=${msg/id}&@action=edit">remove</a>
       </td>
      </tr>
     </tal:block>

     <tal:block tal:condition="request/form/@whole_messages/value | python:0">
      <tr><th colspan="2" class="header">Messages</th>
          <th class="header">
            <a href="?@whole_messages=">show only summaries</a>
          </th>
      </tr>
      <tal:block tal:repeat="msg context/messages">
       <tr>
        <th tal:content="msg/author">author</th>
        <th class="date" tal:content="msg/date/pretty">date</th>
        <th style="text-align: right">
         (<a tal:attributes="href string:?@remove@messages=${msg/id}&@action=edit">remove</a>)
        </th>
       </tr>
       <tr><td colspan="3" tal:content="msg/content"></td></tr>
      </tal:block>
     </tal:block>
    </table>

#### Setting up a "wizard" (or "druid") for controlled adding of issues

1. Set up the page templates you wish to use for data input. My wizard is going to be a two-step process: first figuring out what category of issue the user is submitting, and then getting details specific to that category. The first page includes a table of help, explaining what the category names mean, and then the core of the form:

       <form method="POST" onSubmit="return submit_once()"
             enctype="multipart/form-data">
         <input type="hidden" name="@template" value="add_page1">
         <input type="hidden" name="@action" value="page1_submit">

         <strong>Category:</strong>
         <tal:block tal:replace="structure context/category/menu" />
         <input type="submit" value="Continue">
       </form>

   The next page has the usual issue entry information, with the addition of the following form fragments:

       <form method="POST" onSubmit="return submit_once()"
             enctype="multipart/form-data"
             tal:condition="context/is_edit_ok"
             tal:define="cat request/form/category/value">

         <input type="hidden" name="@template" value="add_page2">
         <input type="hidden" name="@required" value="title">
         <input type="hidden" name="category" tal:attributes="value cat">
          .
          .
          .
       </form>

   Note that later in the form, I use the value of "cat" to decide which form elements should be displayed. For example:

       <tal:block tal:condition="python:cat in '6 10 13 14 15 16 17'.split()">
        <tr>
         <th>Operating System</th>
         <td tal:content="structure context/os/field"></td>
        </tr>
        <tr>
         <th>Web Browser</th>
         <td tal:content="structure context/browser/field"></td>
        </tr>
       </tal:block>

   ... the above section will only be displayed if the category is one of 6, 10, 13, 14, 15, 16 or 17.

3. Determine what actions need to be taken between the pages - these are usually to validate user choices and determine what page is next. Now encode those actions in a new `Action` class (see defining new web actions):

       from roundup.cgi.actions import Action

       class Page1SubmitAction(Action):
           def handle(self):
               ''' Verify that the user has selected a category, and then move
                   on to page 2.
               '''
               category = self.form['category'].value
               if category == '-1':
                   self.error_message.append('You must select a category of report')
                   return
               # everything's ok, move on to the next page
               self.template = 'add_page2'

       def init(instance):
           instance.registerAction('page1_submit', Page1SubmitAction)

4. Use the usual "new" action as the `@action` on the final page, and you're done (the standard context/submit method can do this for you).

## Debugging Trackers

There are three switches in tracker configs that turn on debugging in Roundup:

1. web :: debug
2. mail :: debug
3. logging :: level

See the config.ini file or the tracker configuration section above for more information.

Additionally, the `roundup-server.py` script has its own debugging mode in which it reloads edited templates immediately when they are changed, rather than requiring a web server restart.