Template::Provider
Template::Provider(3)User Contributed Perl DocumentationTemplate::Provider(3)
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 tem-
plate documents. This object may be sub-classed to provide more spe-
cific facilities for loading, or otherwise providing access to tem-
plates.
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 "Tem-
plate::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, STA-
TUS_ERROR)" is returned, where $error is the error message generated.
If the TOLERANT option is set the the method returns "(undef, STA-
TUS_DECLINED)" instead of returning an error.
store($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 subrou-
tines 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 send-
ing 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 con-
figuration 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 dis-
abled 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 han-
dle 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 tem-
plates 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 "Tem-
plate::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 $template = Template->new({
DEBUG => DEBUG_PROVIDER,
});
SUBCLASSING
The "Template::Provider" module can be subclassed to provide templates
from a different source (e.g. a database). In most cases you’ll just
need to provide custom implementations of the "_template_modified()"
and "_template_content()" methods. If your provider requires and cus-
tom initialisation then you’ll also need to implement a new "_init()"
method.
Caching in memory and on disk will still be applied (if enabled) when
overriding these methods.
_template_modified($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 modifica-
tion 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
perl v5.8.8 2008-08-06 Template::Provider(3)
