Ubuntu Manpage: Template::Provider - Provider module for loading/compiling templates

Provided by: libtemplate-perl_2.27-1build7_amd64

NAME

       Template::Provider - Provider module for loading/compiling templates

SYNOPSIS

           $provider = Template::Provider->new(\%options);

           ($template, $error) = $provider->fetch($name);

DESCRIPTION

       The Template::Provider is used to load, parse, compile and cache template documents. This
       object may be sub-classed to provide more specific facilities for loading, or otherwise
       providing access to templates.

       The Template::Context objects maintain a list of Template::Provider objects which are
       polled in turn (via fetch()) to return a requested template. Each may return a compiled
       template, raise an error, or decline to serve the request, giving subsequent providers a
       chance to do so.

       The Template::Provider can also be subclassed to provide templates from a different
       source, e.g. a database. See SUBCLASSING below.

       This documentation needs work.

PUBLIC METHODS

new(\%options)
Constructor method which instantiates and returns a new "Template::Provider" object. A
reference to a hash array of configuration options may be passed.

See "CONFIGURATION OPTIONS" below for a summary of configuration options and
Template::Manual::Config for full details.

fetch($name)
Returns a compiled template for the name specified. If the template cannot be found then
"(undef, STATUS_DECLINED)" is returned. If an error occurs (e.g. read error, parse error)
then "($error, STATUS_ERROR)" is returned, where $error is the error message generated. If
the TOLERANT option is set the the method returns "(undef, STATUS_DECLINED)" instead of
returning an error.

load($name)
Loads a template without parsing or compiling it. This is used by the the INSERT
directive.

store($name, $template)
Stores the compiled template, $template, in the cache under the name, $name. Susbequent
calls to "fetch($name)" will return this template in preference to any disk-based file.

include_path(\@newpath)
Accessor method for the "INCLUDE_PATH" setting. If called with an argument, this method
will replace the existing "INCLUDE_PATH" with the new value.

paths()
This method generates a copy of the "INCLUDE_PATH" list. Any elements in the list which
are dynamic generators (e.g. references to subroutines or objects implementing a "paths()"
method) will be called and the list of directories returned merged into the output list.

It is possible to provide a generator which returns itself, thus sending this method into
an infinite loop. To detect and prevent this from happening, the $MAX_DIRS package
variable, set to 64 by default, limits the maximum number of paths that can be added to,
or generated for the output list. If this number is exceeded then the method will
immediately return an error reporting as much.

CONFIGURATION OPTIONS

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

   INCLUDE_PATH
       The INCLUDE_PATH option is used to specify one or more directories in which template files
       are located.

           # single path
           my $provider = Template::Provider->new({
               INCLUDE_PATH => '/usr/local/templates',
           });

           # multiple paths
           my $provider = Template::Provider->new({
               INCLUDE_PATH => [ '/usr/local/templates',
                                 '/tmp/my/templates' ],
           });

   ABSOLUTE
       The ABSOLUTE flag is used to indicate if templates specified with absolute filenames (e.g.
       '"/foo/bar"') should be processed. It is disabled by default and any attempt to load a
       template by such a name will cause a '"file"' exception to be raised.

           my $provider = Template::Provider->new({
               ABSOLUTE => 1,
           });

   RELATIVE
       The RELATIVE flag is used to indicate if templates specified with filenames relative to
       the current directory (e.g.  "./foo/bar" or "../../some/where/else") should be loaded. It
       is also disabled by default, and will raise a "file" error if such template names are
       encountered.

           my $provider = Template::Provider->new({
               RELATIVE => 1,
           });

   DEFAULT
       The DEFAULT option can be used to specify a default template which should be used whenever
       a specified template can't be found in the INCLUDE_PATH.

           my $provider = Template::Provider->new({
               DEFAULT => 'notfound.html',
           });

       If a non-existant template is requested through the Template process() method, or by an
       "INCLUDE", "PROCESS" or "WRAPPER" directive, then the "DEFAULT" template will instead be
       processed, if defined. Note that the "DEFAULT" template is not used when templates are
       specified with absolute or relative filenames, or as a reference to a input file handle or
       text string.

   ENCODING
       The Template Toolkit will automatically decode Unicode templates that have a Byte Order
       Marker (BOM) at the start of the file.  This option can be used to set the default
       encoding for templates that don't define a BOM.

           my $provider = Template::Provider->new({
               ENCODING => 'utf8',
           });

       See Encode for further information.

   CACHE_SIZE
       The CACHE_SIZE option can be used to limit the number of compiled templates that the
       module should cache. By default, the CACHE_SIZE is undefined and all compiled templates
       are cached.

           my $provider = Template::Provider->new({
               CACHE_SIZE => 64,   # only cache 64 compiled templates
           });

   STAT_TTL
       The STAT_TTL value can be set to control how long the "Template::Provider" will keep a
       template cached in memory before checking to see if the source template has changed.

           my $provider = Template::Provider->new({
               STAT_TTL => 60,  # one minute
           });

   COMPILE_EXT
       The COMPILE_EXT option can be provided to specify a filename extension for compiled
       template files.  It is undefined by default and no attempt will be made to read or write
       any compiled template files.

           my $provider = Template::Provider->new({
               COMPILE_EXT => '.ttc',
           });

   COMPILE_DIR
       The COMPILE_DIR option is used to specify an alternate directory root under which compiled
       template files should be saved.

           my $provider = Template::Provider->new({
               COMPILE_DIR => '/tmp/ttc',
           });

   TOLERANT
       The TOLERANT flag can be set to indicate that the "Template::Provider" module should
       ignore any errors encountered while loading a template and instead return
       "STATUS_DECLINED".

   PARSER
       The PARSER option can be used to define a parser module other than the default of
       Template::Parser.

           my $provider = Template::Provider->new({
               PARSER => MyOrg::Template::Parser->new({ ... }),
           });

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

           use Template::Constants qw( :debug );

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

SUBCLASSING

       The "Template::Provider" module can be subclassed to provide templates from a different
       source (e.g. a database).  In most cases you'll just need to provide custom
       implementations of the "_template_modified()" and "_template_content()" methods.  If your
       provider requires and custom initialisation then you'll also need to implement a new
       "_init()" method.

       Caching in memory and on disk will still be applied (if enabled) when overriding these
       methods.

   _template_modified($path)
       Returns a timestamp of the $path passed in by calling "stat()".  This can be overridden,
       for example, to return a last modified value from a database.  The value returned should
       be a timestamp value (as returned by "time()", although a sequence number should work as
       well.

   _template_content($path)
       This method returns the content of the template for all "INCLUDE", "PROCESS", and "INSERT"
       directives.

       When called in scalar context, the method returns the content of the template located at
       $path, or "undef" if $path is not found.

       When called in list context it returns "($content, $error, $mtime)", where $content is the
       template content, $error is an error string (e.g. ""$path: File not found""), and $mtime
       is the template modification time.

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.