Template::Provider
Section: User Contributed Perl Documentation (3pm)
Updated: 2022-10-20
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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 $mtime is the template modification
time.
AUTHOR
Andy Wardley <abw@wardley.org> <http://wardley.org/>
COPYRIGHT
Copyright (C) 1996-2007 Andy Wardley. All Rights Reserved.
This module is free software; you can redistribute it and/or
modify it under the same terms as Perl itself.
SEE ALSO
Template, Template::Parser, Template::Context
Index
- NAME
-
- SYNOPSIS
-
- DESCRIPTION
-
- PUBLIC METHODS
-
- new(\%options)
-
- fetch($name)
-
- load($name)
-
- store($name, $template)
-
- include_path(\@newpath)
-
- paths()
-
- CONFIGURATION OPTIONS
-
- INCLUDE_PATH
-
- ABSOLUTE
-
- RELATIVE
-
- DEFAULT
-
- ENCODING
-
- CACHE_SIZE
-
- STAT_TTL
-
- COMPILE_EXT
-
- COMPILE_DIR
-
- TOLERANT
-
- PARSER
-
- DEBUG
-
- SUBCLASSING
-
- _template_modified($path)
-
- _template_content($path)
-
- AUTHOR
-
- COPYRIGHT
-
- SEE ALSO
-
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Time: 20:41:46 GMT, May 23, 2024