=head1 Templates

Templates are used in RT to send notifications, typically email. You have
access to RT data via variables available to you in the scope of the template.
Templates can also be used for some special actions like creating a new ticket
as part of the execution of a scrip.

Each template is split into two sections: a block of headers and a body. These
sections are separated by a blank line. Blank lines are not allowed before
the headers, but can be included in the body as needed after the headers
section.

Templates are processed by the L<Text::Template> module. This module
allows you to embed arbitrary Perl code into your templates. Text wrapped
in curly braces, C<{...}> is interpreted as Perl. See L<Text::Template>
for more information.

=head2 Headers

Your template may specify arbitrary email headers. Each header is a name, a
colon, then a value. So, for example, to specify a subject, you can use:

    Subject: Thanks for your bug report.

=head3 Special Headers

=over

=item Content-Type: text/html

The special header "Content-Type: text/html" tells RT that the template should
be parsed as HTML. RT will automatically make the outgoing message multipart.
That way, recipients who can read only plaintext email will receive something
readable, while users with clients which can display HTML will receive the full
experience. Please be aware that HTML support in mail clients varies greatly,
much more so than different web browsers.

Starting in RT 4.2, HTML templates are included along with plain text templates
for the standard RT notifications.

=back

=head2 Template Types

Templates have a Type which dictates the level of code execution allowed.

Templates of type C<Perl> are evaluated using L<Text::Template>
which allows arbitrary code execution. Only users with the global
C<ExecuteCode> privilege may write templates of type C<Perl>. Prior to
RT 4.0, this was the only type of Template available.

Templates of type C<Simple> permit only simple variable interpolation.
No special privilege beyond C<ModifyTemplate> is needed to write C<Simple>
templates.

For both types of templates, text between curly braces C<{ ... }> is
interpolated. For C<Perl> templates, this text can be any code (see
L<Text::Template/Details>). For C<Simple> templates, only simple variables
are permitted; for example C<{ $TicketSubject }>.

=head2 Variables

=head3 Perl templates

The variables that your templates may use include:

=over 4

=item C<$Transaction>

The transaction object.

=item C<$rtname>

The value of the "rtname" config variable.

=item C<$Ticket>

The ticket object. This is only set during a ticket transaction.

=item C<$Requestor>

This is not an object, but the name of the first requestor on the ticket.
If this is not what you need, inspect C<< $Ticket->Requestors >>.

=item C<loc("text")>

A localization function. See L<Locale::Maketext>.

=back

The C<$Transaction> and C<$Ticket> objects are particularly useful. For
example, here are some values you can get from each:

    $Ticket->Status      # Current status
    $Ticket->Owner       # Current owner
    $Ticket->FirstCustomFieldValue('CustomFieldName') # CF value
    $Ticket->DueAsString # Current due date as a string
    $Ticket->DueObj      # Due as an RT::Date object
    $Ticket->QueueObj    # Queue object for this ticket

    $Transaction->Type     # Type of transaction
    $Transaction->OldValue # Previous value, if type is Set
    $Transaction->NewValue # New value, if type is Set
    $Transaction->CreatorObj->EmailAddress # Email address of trans creator

You can see the methods available in the L<RT::Ticket> and L<RT::Transaction>
documentation.

=head3 Selected Simple template variables

Since method calls are not allowed in simple templates, many common
method results have been placed into scalar variables for the template's
use.  Among them:

=over 4

=item $TicketId

=item $TicketSubject

=item $TicketStatus

=item $TicketQueueName

=item $TicketOwnerName

=item $TicketOwnerEmailAddress

=item $TicketCF(Name)

For example, C<$TicketCFDepartment>.  For CFs with more complicated
names, all non-word characters (anything that is not letters, numbers,
or underscores) are stripped to determine the appropriate variable name.

=item $TransactionType

=item $TransactionField

=item $TransactionOldValue

=item $TransactionNewValue

=item $TransactionData

=item $TransactionContent

=item $TransactionDescription

=item $TransactionBriefDescription

=item $TransactionCF(Name)

For example, C<$TransactionCFLocation>.

=back

=head2 Templates Provided with RT

RT comes with a set of templates for the default notifications. As you start to
customize your templates, these templates are a good place to look for
examples. As you customize, it can be helpful to create new templates and
update your scrips to reference your new templates. This leaves the original RT
templates in place for easy reference.

Starting in RT 4.2, each template has a plain text version and an HTML
version. For example, the "Correspondence" template is the plain text version
of the default template for correspondence (replies) and the "Correspondence in
HTML" template is the same template formatted in HTML. The 4.2 upgrade provides
a C<switch-templates-to> script to switch all default templates from plain text
to HTML or the reverse. See the L<UPGRADING-4.2> notes for details.

=cut