Template::Service(3)					User Contributed Perl Documentation				      Template::Service(3)

NAME

       Template::Service - General purpose template processing service

SYNOPSIS

	   use Template::Service;

	   my $service = Template::Service->new({
	       PRE_PROCESS  => [ 'config', 'header' ],
	       POST_PROCESS => 'footer',
	       ERROR	    => {
		   user     => 'user/index.html',
		   dbi	    => 'error/database',
		   default  => 'error/default',
	       },
	   });

	   my $output = $service->process($template_name, \%replace)
	       || die $service->error(), "
";

DESCRIPTION

       The "Template::Service" module implements an object class for providing a consistent template processing service.

       Standard header (PRE_PROCESS) and footer (POST_PROCESS) templates may be specified which are prepended and appended to all templates
       processed by the service (but not any other templates or blocks "INCLUDE"d or "PROCESS"ed from within). An ERROR hash may be specified
       which redirects the service to an alternate template file in the case of uncaught exceptions being thrown. This allows errors to be
       automatically handled by the service and a guaranteed valid response to be generated regardless of any processing problems encountered.

       A default "Template::Service" object is created by the Template module.	Any "Template::Service" options may be passed to the Template
       new() constructor method and will be forwarded to the Template::Service constructor.

	   use Template;

	   my $template = Template->new({
	       PRE_PROCESS  => 'header',
	       POST_PROCESS => 'footer',
	   });

       Similarly, the "Template::Service" constructor will forward all configuration parameters onto other default objects (e.g.
       Template::Context) that it may need to instantiate.

       A "Template::Service" object (or subclass) can be explicitly instantiated and passed to the Template new() constructor method as the
       SERVICE item.

	   use Template;
	   use Template::Service;

	   my $service = Template::Service->new({
	       PRE_PROCESS  => 'header',
	       POST_PROCESS => 'footer',
	   });

	   my $template = Template->new({
	       SERVICE => $service,
	   });

       The "Template::Service" module can be sub-classed to create custom service handlers.

	   use Template;
	   use MyOrg::Template::Service;

	   my $service = MyOrg::Template::Service->new({
	       PRE_PROCESS  => 'header',
	       POST_PROCESS => 'footer',
	       COOL_OPTION  => 'enabled in spades',
	   });

	   my $template = Template->new({
	       SERVICE => $service,
	   });

       The Template module uses the Template::Config service() factory method to create a default service object when required. The
       $Template::Config::SERVICE package variable may be set to specify an alternate service module. This will be loaded automatically and its
       new() constructor method called by the service() factory method when a default service object is required. Thus the previous example could
       be written as:

	   use Template;

	   $Template::Config::SERVICE = 'MyOrg::Template::Service';

	   my $template = Template->new({
	       PRE_PROCESS  => 'header',
	       POST_PROCESS => 'footer',
	       COOL_OPTION  => 'enabled in spades',
	   });

METHODS

   new(\%config)
       The "new()" constructor method is called to instantiate a "Template::Service" object.  Configuration parameters may be specified as a HASH
       reference or as a list of "name => value" pairs.

	   my $service1 = Template::Service->new({
	       PRE_PROCESS  => 'header',
	       POST_PROCESS => 'footer',
	   });

	   my $service2 = Template::Service->new( ERROR => 'error.html' );

       The "new()" method returns a "Template::Service" object or "undef" on error. In the latter case, a relevant error message can be retrieved
       by the error() class method or directly from the $Template::Service::ERROR package variable.

	   my $service = Template::Service->new(\%config)
	       || die Template::Service->error();

	   my $service = Template::Service->new(\%config)
	       || die $Template::Service::ERROR;

   process($input, \%replace)
       The "process()" method is called to process a template specified as the first parameter, $input. This may be a file name, file handle (e.g.
       "GLOB" or "IO::Handle") or a reference to a text string containing the template text. An additional hash reference may be passed containing
       template variable definitions.

       The method processes the template, adding any PRE_PROCESS or POST_PROCESS templates defined, and returns the output text. An uncaught
       exception thrown by the template will be handled by a relevant ERROR handler if defined. Errors that occur in the PRE_PROCESS or
       POST_PROCESS templates, or those that occur in the main input template and aren't handled, cause the method to return "undef" to indicate
       failure. The appropriate error message can be retrieved via the error() method.

	   $service->process('myfile.html', { title => 'My Test File' })
	       || die $service->error();

   context()
       Returns a reference to the internal context object which is, by default, an instance of the Template::Context class.

CONFIGURATION OPTIONS

       The following list summarises the configuration options that can be provided to the "Template::Service" new() constructor. Please consult
       Template::Manual::Config for further details and examples of each configuration option in use.

   PRE_PROCESS, POST_PROCESS
       The PRE_PROCESS and POST_PROCESS options may be set to contain the name(s) of template files which should be processed immediately before
       and/or after each template. These do not get added to templates processed into a document via directives such as "INCLUDE" "PROCESS",
       "WRAPPER", etc.

	   my $service = Template::Service->new({
	       PRE_PROCESS  => 'header',
	       POST_PROCESS => 'footer',
	   };

       Multiple templates may be specified as a reference to a list.  Each is processed in the order defined.

	   my $service = Template::Service->new({
	       PRE_PROCESS  => [ 'config', 'header' ],
	       POST_PROCESS => 'footer',
	   };

   PROCESS
       The PROCESS option may be set to contain the name(s) of template files which should be processed instead of the main template passed to the
       "Template::Service" process() method. This can be used to apply consistent wrappers around all templates, similar to the use of PRE_PROCESS
       and POST_PROCESS templates.

	   my $service = Template::Service->new({
	       PROCESS	=> 'content',
	   };

	   # processes 'content' instead of 'foo.html'
	   $service->process('foo.html');

       A reference to the original template is available in the "template" variable.  Metadata items can be inspected and the template can be
       processed by specifying it as a variable reference (i.e. prefixed by '"$"') to an "INCLUDE", "PROCESS" or "WRAPPER" directive.

       Example "PROCESS" template:

	   <html>
	     <head>
	       <title>[% template.title %]</title>
	     </head>
	     <body>
	     [% PROCESS $template %]
	     </body>
	   </html>

   ERROR
       The ERROR (or "ERRORS" if you prefer) configuration item can be used to name a single template or specify a hash array mapping exception
       types to templates which should be used for error handling. If an uncaught exception is raised from within a template then the appropriate
       error template will instead be processed.

       If specified as a single value then that template will be processed for all uncaught exceptions.

	   my $service = Template::Service->new({
	       ERROR => 'error.html'
	   });

       If the ERROR/ERRORS item is a hash reference the keys are assumed to be exception types and the relevant template for a given exception
       will be selected. A "default" template may be provided for the general case.

	   my $service = Template::Service->new({
	       ERRORS => {
		   user     => 'user/index.html',
		   dbi	    => 'error/database',
		   default  => 'error/default',
	       },
	   });

   AUTO_RESET
       The AUTO_RESET option is set by default and causes the local "BLOCKS" cache for the Template::Context object to be reset on each call to
       the Template process() method.  This ensures that any "BLOCK"s defined within a template will only persist until that template is finished
       processing.

   DEBUG
       The DEBUG option can be used to enable debugging messages from the "Template::Service" module by setting it to include the "DEBUG_SERVICE"
       value.

	   use Template::Constants qw( :debug );

	   my $template = Template->new({
	       DEBUG => DEBUG_SERVICE,
	   });

AUTHOR

       Andy Wardley <abw@wardley.org> <http://wardley.org/>

COPYRIGHT

       Copyright (C) 1996-2007 Andy Wardley.  All Rights Reserved.

       This module is free software; you can redistribute it and/or modify it under the same terms as Perl itself.

SEE ALSO

       Template, Template::Context

POD ERRORS

       Hey! The above document had some coding errors, which are explained below:

       Around line 517:
	   alternative text 'ERROR/ERRORS' contains non-escaped | or /

perl v5.16.3							    2011-12-20						      Template::Service(3)