Template(3pm)

NAME

Template - Front-end module to the Template Toolkit

SYNOPSIS

use Template;

# some useful options (see below for full list)
my $config = {
    INCLUDE_PATH => '/search/path',  # or list ref
    INTERPOLATE  => 1,               # expand "$var" in plain text
    POST_CHOMP   => 1,               # cleanup whitespace
    PRE_PROCESS  => 'header',        # prefix each template
    EVAL_PERL    => 1,               # evaluate Perl code blocks
};

# create Template object
my $template = Template->new($config);

# define template variables for replacement
my $vars = {
    var1  => $value,
    var2  => \%hash,
    var3  => \@list,
    var4  => \&code,
    var5  => $object,
};

# specify input filename, or file handle, text reference, etc.
my $input = 'myfile.html';

# process input template, substituting variables
$template->process($input, $vars)
    || die $template->error();

DESCRIPTION

This documentation describes the Template module which is the direct
Perl interface into the Template Toolkit. It covers the use of the
module and gives a brief summary of configuration options and template directives. Please see Template::Manual for the complete reference
manual which goes into much greater depth about the features and use of the Template Toolkit. The Template::Tutorial is also available as an
introductory guide to using the Template Toolkit.

METHODS

new(\%config): The "new()" constructor method (implemented by the Template::Base base class) instantiates a new "Template" object. A reference to a hash
array of configuration items may be passed as a parameter.

my $tt = Template->new({
INCLUDE_PATH => '/usr/local/templates',
EVAL_PERL => 1,

}) || die $Template::ERROR, "\n";; A reference to a new "Template" object is returned, or undef on error. In the latter case, the error message can be retrieved by calling
error() as a class method or by examining the $Template::ERROR package variable directly.

my $tt = Template->new(\%config)
|| die Template->error(), "\n";

my $tt = Template->new(\%config)

|| die $Template::ERROR, "\n";
For convenience, configuration items may also be specified as a list of items instead of a hash array reference. These are automatically folded into a hash array by the constructor.: my $tt = Template->new(INCLUDE_PATH => '/tmp', POST_CHOMP => 1)
|| die $Template::ERROR, "\n";
process($template, \%vars, $output, %options): The "process()" method is called to process a template. The first
parameter indicates the input template as one of: a filename relative
to "INCLUDE_PATH", if defined; a reference to a text string containing the template text; or a file handle reference (e.g. "IO::Handle" or
sub-class) or "GLOB" (e.g. "\*STDIN"), from which the template can be
read. A reference to a hash array may be passed as the second
parameter, containing definitions of template variables.

# filename
$tt->process('welcome.tt2')
|| die $tt->error(), "\n";

# text reference
$text = "[% INCLUDE header %]\nHello world!\n[% INCLUDE footer %]";
$tt->process(\$text)

|| die $tt->error(), "\n";

# file handle (GLOB)
$tt->process(\*DATA)

|| die $tt->error(), "\n";

__END__
[% INCLUDE header %]
This is a template defined in the __END__ section which is
accessible via the DATA "file handle".
[% INCLUDE footer %]; By default, the processed template output is printed to "STDOUT". The
"process()" method then returns 1 to indicate success. A third
parameter may be passed to the "process()" method to specify a
different output location. This value may be one of: a plain string
indicating a filename which will be opened (relative to "OUTPUT_PATH", if defined) and the output written to; a file GLOB opened ready for
output; a reference to a scalar (e.g. a text string) to which
output/error is appended; a reference to a subroutine which is called, passing the output as a parameter; or any object reference which
implements a "print()" method (e.g. "IO::Handle", "Apache::Request",
etc.) which will be called, passing the generated output as a
parameter.; Examples:

# output filename
$tt->process('welcome.tt2', $vars, 'welcome.html')
|| die $tt->error(), "\n";

# reference to output subroutine
sub myout {

my $output = shift;
...

}
$tt->process('welcome.tt2', $vars, \&myout)

|| die $tt->error(), "\n";

# reference to output text string
my $output = '';
$tt->process('welcome.tt2', $vars, \$output)

|| die $tt->error(), "\n";

print "output: $output\n";; In an Apache/mod_perl handler:

sub handler {
my $req = shift;

# ...your code here...

# direct output to Apache::Request via $req->print($output)
$tt->process($file, $vars, $req) || do {
$req->log_reason($tt->error());
return SERVER_ERROR;

};
return OK;

}; After the optional third output argument can come an optional reference to a hash or a list of "(name, value)" pairs providing further options for the output. The only option currently supported is "binmode"
which, when set to any true value will ensure that files created (but
not any existing file handles passed) will be set to binary mode.

# either: hash reference of options
$tt->process($infile, $vars, $outfile, { binmode => 1 })
|| die $tt->error(), "\n";

# or: list of name, value pairs
$tt->process($infile, $vars, $outfile, binmode => 1)

|| die $tt->error(), "\n";
Alternately, the "binmode" argument can specify a particular IO layer such as ":utf8".: $tt->process($infile, $vars, $outfile, binmode => ':utf8')
|| die $tt->error(), "\n";
The "OUTPUT" configuration item can be used to specify a default output location other than "\*STDOUT". The "OUTPUT_PATH" specifies a directory which should be prefixed to all output locations specified as filenames.: my $tt = Template->new({
OUTPUT => sub { ... }, # default
OUTPUT_PATH => '/tmp',; ...
}) || die Template->error(), "\n";; # use default OUTPUT (sub is called)
$tt->process('welcome.tt2', $vars)
|| die $tt->error(), "\n";; # write file to '/tmp/welcome.html'
$tt->process('welcome.tt2', $vars, 'welcome.html')
|| die $tt->error(), "\n";
The "process()" method returns 1 on success or "undef" on error. The error message generated in the latter case can be retrieved by calling the error() method. See also "CONFIGURATION SUMMARY" which describes how error handling may be further customised.
error(): When called as a class method, it returns the value of the $ERROR
package variable. Thus, the following are equivalent.

my $tt = Template->new()
|| die Template->error(), "\n";

my $tt = Template->new()

|| die $Template::ERROR, "\n";
When called as an object method, it returns the value of the internal "_ERROR" variable, as set by an error condition in a previous call to process().: $tt->process('welcome.tt2')
|| die $tt->error(), "\n";
Errors are represented in the Template Toolkit by objects of the Template::Exception class. If the process() method returns a false value then the "error()" method can be called to return an object of this class. The type() and info() methods can called on the object to retrieve the error type and information string, respectively. The as_string() method can be called to return a string of the form "$type - $info". This method is also overloaded onto the stringification operator allowing the object reference itself to be printed to return the formatted error string.: $tt->process('somefile') || do {
my $error = $tt->error();
print "error type: ", $error->type(), "\n";
print "error info: ", $error->info(), "\n";
print $error, "\n";; };
service(): The "Template" module delegates most of the effort of processing
templates to an underlying Template::Service object. This method
returns a reference to that object.
context(): The Template::Service module uses a core Template::Context object for
runtime processing of templates. This method returns a reference to
that object and is equivalent to "$template->service->context()".

CONFIGURATION SUMMARY

The following list gives a short summary of each Template Toolkit
configuration option. See Template::Manual::Config for full details.
Template Style and Parsing Options: START_TAG, END_TAG; Define tokens that indicate start and end of directives (default:
'"[%"' and '"%]"').; TAG_STYLE; Set "START_TAG" and "END_TAG" according to a pre-defined style
(default: '"template"', as above).; PRE_CHOMP, POST_CHOMP; Removes whitespace before/after directives (default: 0/0).; TRIM; Remove leading and trailing whitespace from template output (default:
0).; INTERPOLATE; Interpolate variables embedded like $this or "${this}" (default: 0).; ANYCASE; Allow directive keywords in lower case (default: 0 - UPPER only).
Template Files and Blocks: INCLUDE_PATH; One or more directories to search for templates.; DELIMITER; Delimiter for separating paths in "INCLUDE_PATH" (default: '":"').; ABSOLUTE; Allow absolute file names, e.g. "/foo/bar.html" (default: 0).; RELATIVE; Allow relative filenames, e.g. "../foo/bar.html" (default: 0).; DEFAULT; Default template to use when another not found.; BLOCKS; Hash array pre-defining template blocks.; AUTO_RESET; Enabled by default causing "BLOCK" definitions to be reset each time a template is processed. Disable to allow "BLOCK" definitions to
persist.; RECURSION; Flag to permit recursion into templates (default: 0).
Template Variables: VARIABLES; Hash array of variables and values to pre-define in the stash.
Runtime Processing Options: EVAL_PERL; Flag to indicate if "PERL"/"RAWPERL" blocks should be processed
(default: 0).; PRE_PROCESS, POST_PROCESS; Name of template(s) to process before/after main template.; PROCESS; Name of template(s) to process instead of main template.; ERROR; Name of error template or reference to hash array mapping error types
to templates.; OUTPUT; Default output location or handler.; OUTPUT_PATH; Directory into which output files can be written.; DEBUG; Enable debugging messages.
Caching and Compiling Options: CACHE_SIZE; Maximum number of compiled templates to cache in memory (default: undef - cache all); COMPILE_EXT; Filename extension for compiled template files (default: undef - don't compile).; COMPILE_DIR; Root of directory in which compiled template files should be written
(default: undef - don't compile).
Plugins and Filters: PLUGINS; Reference to a hash array mapping plugin names to Perl packages.; PLUGIN_BASE; One or more base classes under which plugins may be found.; LOAD_PERL; Flag to indicate regular Perl modules should be loaded if a named
plugin can't be found (default: 0).; FILTERS; Hash array mapping filter names to filter subroutines or factories.
Customisation and Extension: LOAD_TEMPLATES; List of template providers.; LOAD_PLUGINS; List of plugin providers.; LOAD_FILTERS; List of filter providers.; TOLERANT; Set providers to tolerate errors as declinations (default: 0).; SERVICE; Reference to a custom service object (default: Template::Service).; CONTEXT; Reference to a custom context object (default: Template::Context).; STASH; Reference to a custom stash object (default: Template::Stash).; PARSER; Reference to a custom parser object (default: Template::Parser).; GRAMMAR; Reference to a custom grammar object (default: Template::Grammar).

DIRECTIVE SUMMARY

The following list gives a short summary of each Template Toolkit
directive. See Template::Manual::Directives for full details.
GET: Evaluate and print a variable or value.

[% GET variable %] # 'GET' keyword is optional
[% variable %]
[% hash.key %]
[% list.n %]
[% code(args) %]
[% obj.meth(args) %]
[% "value: $var" %]
CALL: As per GET but without printing result (e.g. call code)

[% CALL variable %]
SET: Assign a values to variables.

[% SET variable = value %] # 'SET' also optional
[% variable = other_variable
variable = 'literal text @ $100'
variable = "interpolated text: $var"
list = [ val, val, val, val, ... ]
list = [ val..val ]
hash = { var => val, var => val, ... }

%]
DEFAULT: Like SET, but variables are only set if currently unset (i.e. have no
true value).

[% DEFAULT variable = value %]
INSERT: Insert a file without any processing performed on the contents.

[% INSERT legalese.txt %]
PROCESS: Process another template file or block and insert the generated output. Any template BLOCKs or variables defined or updated in the "PROCESS"ed template will thereafter be defined in the calling template.

[% PROCESS template %]
[% PROCESS template var = val, ... %]
INCLUDE: Similar to "PROCESS", but using a local copy of the current variables. Any template "BLOCK"s or variables defined in the "INCLUDE"d template
remain local to it.

[% INCLUDE template %]
[% INCLUDE template var = val, ... %]
WRAPPER: The content between the "WRAPPER" and correspondng "END" directives is first evaluated, with the output generated being stored in the
"content" variable. The named template is then process as per
"INCLUDE".

[% WRAPPER layout %]
Some template markup [% blah %]...

[% END %]; A simple layout template might look something like this:

Your header here...
[% content %]
Your footer here...
BLOCK: Define a named template block for INCLUDE, PROCESS and WRAPPER to use.

[% BLOCK hello %]
Hello World

[% END %]

[% INCLUDE hello %]
FOREACH: Repeat the enclosed "FOREACH" ... "END" block for each value in the
list.

[% FOREACH variable IN [ val, val, val ] %] # either
[% FOREACH variable IN list %] # or
The variable is set to [% variable %]

[% END %]
WHILE: The block enclosed between "WHILE" and "END" block is processed while
the specified condition is true.

[% WHILE condition %]
content

[% END %]
IF / UNLESS / ELSIF / ELSE: The enclosed block is processed if the condition is true / false.

[% IF condition %]
content

[% ELSIF condition %]

content

[% ELSE %]

content

[% END %]

[% UNLESS condition %]

content

[% # ELSIF/ELSE as per IF, above %]

content

[% END %]
SWITCH / CASE: Multi-way switch/case statement.

[% SWITCH variable %]
[% CASE val1 %]
content

[% CASE [ val2, val3 ] %]

content

[% CASE %] # or [% CASE DEFAULT %]

content

[% END %]
MACRO: Define a named macro.

[% MACRO name <directive> %]
[% MACRO name(arg1, arg2) <directive> %]
...
[% name %]
[% name(val1, val2) %]
FILTER: Process enclosed "FILTER" ... "END" block then pipe through a filter.

[% FILTER name %] # either
[% FILTER name( params ) %] # or
[% FILTER alias = name( params ) %] # or
content

[% END %]
USE: Load a plugin module (see "Template::<Manual::Plugins"), or any regular Perl module when the "LOAD_PERL" option is set.

[% USE name %] # either
[% USE name( params ) %] # or
[% USE var = name( params ) %] # or
...
[% name.method %]
[% var.method %]
PERL / RAWPERL: Evaluate enclosed blocks as Perl code (requires the "EVAL_PERL" option to be set).

[% PERL %]
# perl code goes here
$stash->set('foo', 10);
print "set 'foo' to ", $stash->get('foo'), "\n";
print $context->include('footer', { var => $val });

[% END %]

[% RAWPERL %]

# raw perl code goes here, no magic but fast.
$output .= 'some output';

[% END %]
TRY / THROW / CATCH / FINAL: Exception handling.

[% TRY %]
content
[% THROW type info %]

[% CATCH type %]

catch content
[% error.type %] [% error.info %]

[% CATCH %] # or [% CATCH DEFAULT %]

content

[% FINAL %]

this block is always processed

[% END %]
NEXT: Jump straight to the next item in a "FOREACH" or "WHILE" loop.

[% NEXT %]
LAST: Break out of "FOREACH" or "WHILE" loop.

[% LAST %]
RETURN: Stop processing current template and return to including templates.

[% RETURN %]
STOP: Stop processing all templates and return to caller.

[% STOP %]
TAGS: Define new tag style or characters (default: "[%" "%]").

[% TAGS html %]
[% TAGS  %]
COMMENTS: Ignored and deleted.

[% # this is a comment to the end of line
foo = 'bar'

%]

[%# placing the '#' immediately inside the directive

tag comments out the entire directive

%]

AUTHOR

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

VERSION

Template Toolkit version 2.20_1, released April 2009.

COPYRIGHT

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

docs.sk

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