choosing a templating system

Perrin Harkins

The Ultimate Templating SystemThe Ultimate Templating System

$HTML =~ s/\$(\w+)/${$1}/g;

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Why bother?Why bother?

Consistency of appearanceReusabilityBetter isolation from changesDivision of labor

Template TaxonomyTemplate Taxonomy

Execution modelLanguageParsingFramework or just templates

Execution ModelExecution Model

Callback– Mason, Embperl, Apache::ASP

mod_perl

Perl space

template

Execution ModelExecution Model

Pipeline– HTML::Template, Template Toolkit

mod_perl Perl space template

CallbackCallback

Pro– Easy to componentize pages– Quick to get started with

Con– Messy for branching

PipelinePipeline

Pro– Handles branching cleanly– Possible tuning opportunities

Con– Slower to get started with

LanguageLanguage

Burn baby burn– in-line Perl– mini-languages

In-line Perl sampleIn-line Perl sample

<% my $product = Product->load('sku' => 'bar1234'); %>

<% if ($product->isbn) { %>

It's a book!

<% } else { %>

It's NOT a book!

<% } %>

<% foreach my $item (@{$product->related}) { %>

You might also enjoy <% $item->name %>.

<% } %>

Mini-language sampleMini-language sample

[% USE product(sku=bar1234) %]

[% IF product.isbn %]

It's a book!

[% ELSE %]

It's NOT a book!

[% END %]

[% FOREACH item = product.related %]

You might also enjoy [% item.name %].

[% END %]

ParsingParsing

CompiledCached parse treeRepeated parse

template Perl codecompiledbytecode

Frameworks vs. Just TemplatesFrameworks vs. Just Templates

URL mappingSession trackingOutput cachingForm handlingDebuggingOther options

– libservlet, Apache::PageKit, OpenInteract, CGI::Application

The ContendersThe Contenders

SSI HTML::Mason HTML::Embperl Apache::AxKit Apache::ASP Text::Template Template Toolkit HTML::Template

SSISSI

CallbackMini-languageRepeated Parse#perlApache::SSI for filtering

HTML::MasonHTML::Mason

Callback (mostly) In-line Perl Compiled Publishing roots<%init> Caching Parameter checking Debug files

Text::TemplateText::Template

CallbackIn-line PerlCompiledSafeIncludes not includedCache it yourself

Apache::ASPApache::ASP

Callback In-line Perl Compiled Built-in objects URL-munging sessions XMLSubs, XSLT

<site:header page="Page Title" /> Sticky widgets Compressed output No RDBMS session storage built in

Apache::AxKitApache::AxKit

Pipeline (usually) Mini-language or in-line Perl Compiled Stylesheet

– XML::XSLT, XML::Sablotron, XPathScript Provider

– XSP, XSP taglibs Caching Compression

HTML::EmbperlHTML::Embperl

Callback In-line Perl Compiled Safe%fdat, %udat HTML support

– TABLE, INPUT, query strings, etc. EmbperlObject Control structures

Template ToolkitTemplate Toolkit

Pipeline (sorta) Mini-language Compiled Dot notation: foo.bar.baz Macros Filters Plugins

– XML, DBI– Dates, prices, multi-column

ttree, Splash library

HTML::TemplateHTML::Template

PipelineMini-languageCached Parse TreeFast and simpleTemplates can be cached in shared

memory or disk

Honorable mentionsHonorable mentions

ePerlApache::XPPCGI::FastTemplateHTML_Tree

PerformancePerformance

Don’t start with your templating system!

Benchmarks– http://www.chamas.com/bench/hello.tar.gz

CGI concerns

Frameworkor Just Templates

Pipeline or Callback

Parsing Method Language

HTML::Mason Framework Callback Compiled Perl

Template Toolkit Just Templates Pipeline Compiled Mini-language

Apache::ASP Framework Callback Compiled Perl

HTML::Embperl Framework Callback Compiled Perl

SSI Just Templates Callback Repeated Parse Mini-language

AxKit Framework Pipeline Compiled or Cached Parse Tree

Perl and XSL and Mini-Language(s)

HTML::Template Just Templates Pipeline Cached Parse Tree

Mini-language

Text::Template Just Templates Callback Compiled Perl

UpdatesUpdates

Article to be published on mod_perl list.

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perrin@elem.com