Template::Plugins - provider module for loading and instantiating plugins
use Template::Plugins; $plugin_provider = Template::Plugins->new(\%options); ($plugin, $error) = $plugin_provider->fetch($name, @args);
The Template::Plugins module defines a provider class which can be used to load and instantiate Template Toolkit plugin modules.
Constructor method which instantiates and returns a reference to a Template::Plugins object. A reference to a hash array of configuration items may be passed as a parameter. These are described below.
Note that the Template.pm front-end module creates a Template::Plugins provider, passing all configuration items. Thus, the examples shown below in the form:
$plugprov = Template::Plugins->new({ PLUGIN_BASE => 'MyTemplate::Plugin', LOAD_PERL => 1, ... });
can also be used via the Template module as:
$ttengine = Template->new({ PLUGIN_BASE => 'MyTemplate::Plugin', LOAD_PERL => 1, ... });
as well as the more explicit form of:
$plugprov = Template::Plugins->new({ PLUGIN_BASE => 'MyTemplate::Plugin', LOAD_PERL => 1, ... }); $ttengine = Template->new({ LOAD_PLUGINS => [ $plugprov ], });
Called to request that a plugin of a given name be provided. The relevant module is first loaded (if necessary) and the load() class method called to return the factory class name (usually the same package name) or a factory object (a prototype). The new() method is then called as a class or object method against the factory, passing all remaining parameters.
Returns a reference to a new plugin object or ($error, STATUS_ERROR) on error. May also return (undef, STATUS_DECLINED) to decline to serve the request. If TOLERANT is set then all errors will be returned as declines.
The following list details the configuration options that can be provided to the Template::Plugins new() constructor.
The PLUGINS options can be used to provide a reference to a hash array that maps plugin names to Perl module names. A number of standard plugins are defined (e.g. 'table', 'cgi', 'dbi', etc.) which map to their corresponding Template::Plugin::* couterpart. These can be redefined by values in the PLUGINS hash.
my $plugins = Template::Plugins->new({ PLUGINS => [ cgi => 'MyOrg::Template::Plugin::CGI', foo => 'MyOrg::Template::Plugin::Foo', bar => 'MyOrg::Template::Plugin::Bar', ], });
The USE directive is used to create plugin objects and does so by calling the plugin() method on the current Template::Context object. If the plugin name is defined in the PLUGINS hash then the corresponding Perl module is loaded via require(). The context then calls the load() class method which should return the class name (default and general case) or a prototype object against which the new() method can be called to instantiate individual plugin objects.
If the plugin name is not defined in the PLUGINS hash then the PLUGIN_BASE and/or LOAD_PERL options come into effect.
If a plugin is not defined in the PLUGINS hash then the PLUGIN_BASE is used to attempt to construct a correct Perl module name which can be successfully loaded.
The PLUGIN_BASE can be specified as a single value or as a reference to an array of multiple values. The default PLUGIN_BASE value, 'Template::Plugin', is always added the the end of the PLUGIN_BASE list (a single value is first converted to a list). Each value should contain a Perl package name to which the requested plugin name is appended.
example 1:
my $plugins = Template::Plugins->new({ PLUGIN_BASE => 'MyOrg::Template::Plugin', }); [% USE Foo %] # => MyOrg::Template::Plugin::Foo or Template::Plugin::Foo
example 2:
my $plugins = Template::Plugins->new({ PLUGIN_BASE => [ 'MyOrg::Template::Plugin', 'YourOrg::Template::Plugin' ], }); [% USE Foo %] # => MyOrg::Template::Plugin::Foo or YourOrg::Template::Plugin::Foo or Template::Plugin::Foo
If a plugin cannot be loaded using the PLUGINS or PLUGIN_BASE approaches then the provider can make a final attempt to load the module without prepending any prefix to the module path. This allows regular Perl modules (i.e. those that don't reside in the Template::Plugin or some other such namespace) to be loaded and used as plugins.
By default, the LOAD_PERL option is set to 0 and no attempt will be made to load any Perl modules that aren't named explicitly in the PLUGINS hash or reside in a package as named by one of the PLUGIN_BASE components.
Plugins loaded using the PLUGINS or PLUGIN_BASE receive a reference to the current context object as the first argument to the new() constructor. Modules loaded using LOAD_PERL are assumed to not conform to the plugin interface. They must provide a new() class method for instantiating objects but it will not receive a reference to the context as the first argument. Plugin modules should provide a load() class method (or inherit the default one from the Template::Plugin base class) which is called the first time the plugin is loaded. Regular Perl modules need not. In all other respects, regular Perl objects and Template Toolkit plugins are identical.
If a particular Perl module does not conform to the common, but not unilateral, new() constructor convention then a simple plugin wrapper can be written to interface to it.
The TOLERANT flag is used by the various Template Toolkit provider modules (Template::Provider, Template::Plugins, Template::Filters) to control their behaviour when errors are encountered. By default, any errors are reported as such, with the request for the particular resource (template, plugin, filter) being denied and an exception raised. When the TOLERANT flag is set to any true values, errors will be silently ignored and the provider will instead return STATUS_DECLINED. This allows a subsequent provider to take responsibility for providing the resource, rather than failing the request outright. If all providers decline to service the request, either through tolerated failure or a genuine disinclination to comply, then a '<resource> not found' exception is raised.
The following plugin modules are distributed with the Template Toolkit.
The Date plugin provides an easy way to generate formatted time and date strings by delegating to the POSIX strftime() routine. See Template::Plugin::Date for further details.
[% USE date %] [% date.format %] # current time/date File last modified: [% date.format(template.modtime) %]
The Format plugin provides a simple way to format text according to a printf()-like format. See Template::Plugin::Format for further details.
[% USE bold = format('<b>%s</b>') %] [% bold('Hello') %]
The URL plugin provides a simple way of contructing URLs from a base part and a variable set of parameters. See Template::Plugin::URL for further details.
[% USE mycgi = url('/cgi-bin/bar.pl', debug=1) %] [% mycgi %] # ==> /cgi/bin/bar.pl?debug=1 [% mycgi(mode='submit') %] # ==> /cgi/bin/bar.pl?mode=submit&debug=1
The Table plugin allows you to format a list of data items into a virtual table by specifying a fixed number of rows or columns, with an optional overlap. See Template::Plugin::Table for further details.
[% USE table(list, rows=10, overlap=1) %] [% FOREACH item = table.col(3) %] [% item %] [% END %]
The CGI plugin is a wrapper around Lincoln Stein's <lstein@genome.wi.mit.edu> CGI.pm module. The plugin is distributed with the Template Toolkit (see Template::Plugin::CGI) and the CGI module itself is distributed with recent versions Perl, or is available from CPAN.
Provides an interface to data stored in a plain text file in a simple delimited format. The first line in the file specifies field names and subsequent lines contain data, delimited by the same non-word character as the fields in the first line. Blank lines and comments (lines starting '#' are ignored). See Template::Plugin::Datafile for further details.
/tmp/mydata:
# define names for each field id : email : name : tel # here's the data fred : fred@here.com : Fred Smith : 555-1234 bill : bill@here.com : Bill White : 555-5678
example:
[% USE userlist = datafile('/tmp/mydata') %] [% FOREACH user = userlist %] [% user.name %] ([% user.id %]) [% END %]
The XML::DOM plugin gives access to the XML Document Object Module via Clark Cooper <cooper@sch.ge.com> and Enno Derksen's <enno@att.com> XML::DOM module. The plugin is distributed with the Template Toolkit (see Template::Plugin::XML::DOM) and requires the XML::DOM module, available from CPAN:
http://www.cpan.org/modules/by-module/XML
The XML::RSS plugin is a simple interface to Jonathan Eisenzopf's <eisen@pobox.com> XML::RSS module. An RSS (Rich Site Summary) file is typically used to store short news 'headlines' describing different links within a site. This plugin allows you to parse RSS files and format the contents accordingly using templates. The plugin is distributed with the Template Toolkit (see Template::Plugin::XML::RSS) and requires the XML::RSS module, also available from CPAN:
The following module is distributed separately from the Template Toolkit.
Simon Matthews <sam@knowledgepool.com> has developed a DBI plugin for the Template Toolkit which brings the full power of Tim Bunce's <Tim.Bunce@ig.co.uk> database interface module (DBI) to your templates. The DBI plugin and the DBI modules themselves are available from CPAN at:
http://www.cpan.org/modules/by-module/Template/ http://www.cpan.org/modules/by-module/DBI/
It might be worthwhile being able to distinguish between absolute module names and those which should be applied relative to PLUGIN_BASE directories. For example, use 'MyNamespace::MyModule' to denote absolute module names (e.g. LOAD_PERL), and 'MyNamespace.MyModule' to denote relative to PLUGIN_BASE.
Andy Wardley <abw@kfs.org>
http://www.template-toolkit.org/ http://www.kfs.org/~abw/
$Revision: 1.1 $
Copyright (C) 1996-2000 Andy Wardley. All Rights Reserved. Copyright (C) 1998-2000 Canon Research Centre Europe Ltd.
This module is free software; you can redistribute it and/or modify it under the same terms as Perl itself.
Template, Template::Plugin, Template::Context
To install Template, copy and paste the appropriate command in to your terminal.
cpanm
cpanm Template
CPAN shell
perl -MCPAN -e shell install Template
For more information on module installation, please visit the detailed CPAN module installation guide.