Text::Xslate - High performance template engine
This document describes Text::Xslate version 0.1057.
use Text::Xslate; use FindBin qw($Bin); my $tx = Text::Xslate->new( # the fillowing options are optional. path => ['.'], cache_dir => "$ENV{HOME}/.xslate_cache", cache => 1, ); my %vars = ( title => 'A list of books', books => [ { title => 'Islands in the stream' }, { title => 'Programming Perl' }, # ... ], ); # for files print $tx->render('hello.tx', \%vars); # for strings my $template = q{ <h1><: $title :></h1> <ul> : for $books -> $book { <li><: $book.title :></li> : } # for </ul> }; print $tx->render_string($template, \%vars);
Text::Xslate is a high performance template engine tuned for persistent applications. This engine introduces the virtual machine paradigm. Templates are compiled into xslate intermediate code, and then executed by the xslate virtual machine.
The concept of Xslate is strongly influenced by Text::MicroTemplate and Template-Toolkit, but the central philosophy of Xslate is different from them. That is, the philosophy is sandboxing that the template logic should not have no access outside the template beyond your permission.
This software is under development. Version 0.1xxx is a developing stage, which may include radical changes. Version 0.2xxx and more will be somewhat stable.
Xslate has a virtual machine written in XS, which is highly optimized for rendering templates.
Here is a result of benchmark/x-rich-env.pl to compare various template engines in "rich" environment where applications are persistent and XS modules are available.
$ perl -Mblib benchmark/x-rich-env.pl Perl/5.10.1 i686-linux Text::Xslate/0.1055 Text::MicroTemplate/0.13 Text::MicroTemplate::Extended/0.11 Template/2.22 Text::ClearSilver/0.10.5.4 HTML::Template::Pro/0.9502 1..4 ok 1 - TT: Template-Toolkit ok 2 - MT: Text::MicroTemplate ok 3 - TCS: Text::ClearSilver ok 4 - HTP: HTML::Template::Pro Benchmarks with 'include' (datasize=100) Rate TT MT TCS HTP Xslate TT 131/s -- -71% -94% -95% -99% MT 444/s 240% -- -80% -84% -97% TCS 2181/s 1570% 391% -- -20% -88% HTP 2739/s 1997% 516% 26% -- -85% Xslate 17772/s 13505% 3899% 715% 549% --
According to this result, Xslate is 100+ times faster than Template-Toolkit. Text::MicroTemplate is a very fast template engine written in pure Perl, but XS-based modules, namely Text::ClearSilver, HTML::Template::Pro and Xslate are faster than Text::MicroTemplate. Moreover, Xslate is even faster than Text::ClearSilver and HTML::Template::Pro.
There are benchmark scripts in the benchmark/ directory.
All the template expressions the engine interpolates into templates are html-escaped automatically, so the output has no possibility to XSS by default.
Xslate supports template cascading, which allows you to extend templates with block modifiers. It is like traditional template inclusion, but is more powerful.
This mechanism is also called as template inheritance.
Xslate is highly extensible. You can add functions and methods to the template engine and even add a new syntax via extending the parser.
Creates a new xslate template engine with options.
Possible options are:
path => \@path // ['.']
Specifies the include paths, which may be directory names or virtual paths, i.e. HASH references which contain $file_name => $content mapping.
$file_name => $content
cache => $level // 1
Sets the cache level.
If $level == 1 (default), Xslate caches compiled templates on the disk, and checks the freshness of the original templates every time.
If $level >= 2, caches will be created but the freshness will not be checked.
$level == 0 creates no caches. It's provided for testing.
cache_dir => $dir // "$ENV{HOME}/.xslate_cache"
Specifies the directory used for caches. If $ENV{HOME} doesn't exist, File::Spec->tmpdir will be used.
$ENV{HOME}
File::Spec->tmpdir
You should specify this option on productions.
function => \%functions
Specifies a function map. A function f may be called as f($arg) or $arg | f.
f
f($arg)
$arg | f
There are a few builtin filters, but they are not overridable.
module => [$module => ?\@import_args, ...]
Imports functions from $module, which may be a function-based or bridge module. Optional @import_args are passed to import as $module->import(@import_args).
import
$module->import(@import_args)
For example:
# for function-based modules my $tx = Text::Xslate->new( module => ['Time::Piece'], ); print $tx->render_string( '<: localtime($x).strftime() :>', { x => time() }, ); # => Wed, 09 Jun 2010 10:22:06 JST # for bridge modules my $tx = Text::Xslate->new( module => ['SomeModule::Bridge::Xslate'], ); print $tx->render_string( '<: $x.some_method() :>', { x => time() }, );
Because you can use function-based modules with the module option, and also can invoke any object methods in templates, Xslate doesn't require specific namespaces for plugins.
module
input_layer => $perliolayers // ':utf8'
Specifies PerlIO layers for reading templates.
verbose => $level // 1
Specifies the verbose level.
If $level == 0, all the possible errors will be ignored.
$level == 0
If $level> >= 1 (default), trivial errors (e.g. to print nil) will be ignored, but severe errors (e.g. for a method to throw the error) will be warned.
$level> >= 1
If $level >= 2, all the possible errors will be warned.
$level >= 2
suffix => $ext // '.tx'
Specify the template suffix, which is used for template cascading.
syntax => $name // 'Kolon'
Specifies the template syntax you want to use.
$name may be a short name (e.g. Kolon), or a fully qualified name (e.g. Text::Xslate::Syntax::Kolon).
Kolon
Text::Xslate::Syntax::Kolon
This option is passed to the compiler directly.
escape => $mode // 'html'
Specifies the escape mode, which is automatically applied to template expressions.
Possible escape modes are html and none.
Note that none mode is provided for non-HTML templates, e.g. mail generators, so you must not to use it for HTML templates because it is unsafe.
none
line_start => $token // $parser_defined_str
Specify the token to start line code as a string, which quotemeta will be applied to.
quotemeta
This option is passed to the parser via the compiler.
tag_start => $str // $parser_defined_str
Specify the token to start inline code as a string, which quotemeta will be applied to.
tag_end => $str // $parser_defined_str
Specify the token to end inline code as a string, which quotemeta will be applied to.
header => \@template_files
Specify the header template files, which are inserted to the head of each template.
This option is passed to the compiler.
footer => \@template_files
Specify the footer template files, which are inserted to the foot of each template.
Renders a template file with variables, and returns the result. \%vars is optional.
Note that $file may be cached according to the cache level.
Renders a template string with variables, and returns the result. \%vars is optional.
Note that $string is never cached, so this may be not suitable for web applications.
Loads $file into memory for following render($file, \%vars). Compiles and saves it as caches if needed.
render($file, \%vars)
It is a good idea to load templates before applications fork. Here is an example to to load all the templates which is in a given path:
my $path = ...; my $tx = Text::Xslate->new( path => [$path], cache_dir => $path, ); find sub { if(/\.tx$/) { my $file = $File::Find::name; $file =~ s/\Q$path\E .//xsm; # fix path names $tx->load_file($file); } }, $path; # fork and render ...
Returns the current Xslate engine while executing. Otherwise returns undef. This method is significant when it is called by template functions and methods.
undef
Returns the current file name while executing. Otherwise returns undef. This method is significant when it is called by template functions and methods.
Returns the current line number while executing. Otherwise returns undef. This method is significant when it is called by template functions and methods.
mark_raw($str :Str) :RawStr
Marks $str as raw, so that the content of $str will be rendered as is, so you have to escape these strings by yourself.
my $tx = Text::Xslate->new(); my $tmpl = 'Mailaddress: <: $email :>'; my %vars = ( email => mark_raw('Foo <foo at example.com>'), ); print $tx->render_string($tmpl, \%email); # => Mailaddress: Foo <foo@example.com>
This function is available in templates as the mark_raw filter, although the use of it is discouraged.
mark_raw
unmark_raw($str :Str) :Str
Clears the raw marker from $str, so that the content of $str will be escaped before rendered.
This function is available in templates as the unmark_raw filter.
unmark_raw
html_escape($str :Str) :RawStr
Escapes html meta characters in $str, and returns it as a raw string (see above). If $str is already a raw string, it returns $str as is.
By default, this function will be automatically applied to all the template expressions.
This function is available in templates as the html filter, but you'd better to use unmark_raw to ensure expressions to be html-escaped.
html
uri_escape($str :Str) :Str
Escapes URI unsafe characters in $str, and returns it.
This function is available in templates as the uri filter.
uri
The xslate(1) command is provided as a CLI to the Text::Xslate module, which is used to process directory trees or to evaluate one liners. For example:
xslate(1)
$ xslate -D name=value -o dest_path src_path $ xslate -e 'Hello, <: $ARGV[0] :> wolrd!' Xslate $ xslate -s TTerse -e 'Hello, [% ARGV.0 %] world!' TTerse
See xslate(1) for details.
Several syntaxes are provided for templates.
Kolon is the default syntax, using <: ... :> inline code and : ... line code, which is explained in Text::Xslate::Syntax::Kolon.
<: ... :>
: ...
Metakolon is the same as Kolon except for using [% ... %] inline code and %% ... line code, instead of <: ... :> and : ....
[% ... %]
%% ...
TTerse is a syntax that is a subset of Template-Toolkit 2 (and partially TT3), which is explained in Text::Xslate::Syntax::TTerse.
There are common notes in Xslate.
Note that nil (i.e. undef in Perl) handling is different from Perl's. Basically it does nothing, but verbose => 2 will produce warnings on it.
verbose => 2
Prints nothing.
Returns nil. That is, nil.foo.bar.baz produces nil.
nil.foo.bar.baz
Returns nil. That is, nil.foo().bar().baz() produces nil.
nil.foo().bar().baz()
Dealt as an empty array.
$var == nil returns true if and only if $var is nil.
$var == nil
Perl 5.8.1 or later.
If you have a C compiler, the XS backend will be used. Otherwise the pure Perl backend will be used.
All complex software has bugs lurking in it, and this module is no exception. If you find a bug please either email me, or add the bug to cpan-RT. Patches are welcome :)
Documents:
Text::Xslate::Manual
Xslate template syntaxes:
Text::Xslate::Syntax::Metakolon
Text::Xslate::Syntax::TTerse
Xslate command:
xlsate
The Xslate web site:
http://xslate.org/
Other template modules that Xslate is influenced by:
Text::MicroTemplate
Text::MicroTemplate::Extended
Text::ClearSilver
Template (Template::Toolkit)
HTML::Template
HTML::Template::Pro
Template::Alloy
Template::Sandbox
Benchmarks:
Template::Benchmark
Thanks to lestrrat for the suggestion to the interface of render(), the contribution of App::Xslate, and a lot of suggestions.
render()
Thanks to tokuhirom for the ideas, feature requests, encouragement, and bug finding.
Thanks to gardejo for the proposal to the name template cascading.
Thanks to jjn1056 to the concept of template overlay (now implemented as cascade with ...).
cascade with ...
Thanks to makamaka for the contribution of Text::Xslate::PP.
Thanks to typester for the various inspirations.
Thanks to clouder for the patch of adding AND and OR to TTerse.
AND
OR
Thanks to punytan for the documentation improvement.
Thanks to chiba for the bug reports and patches.
Fuji, Goro (gfx) <gfuji(at)cpan.org>
Makamaka Hannyaharamitu (makamaka)
Maki, Daisuke (lestrrat)
Copyright (c) 2010, Fuji, Goro (gfx). All rights reserved.
This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself.
To install Text::Xslate, copy and paste the appropriate command in to your terminal.
cpanm
cpanm Text::Xslate
CPAN shell
perl -MCPAN -e shell install Text::Xslate
For more information on module installation, please visit the detailed CPAN module installation guide.