Template engine (web)

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Content (from a database), and "presentation specifications" (in a web template), are combined (through the template engine) to mass-produce web documents.
Content (from a database), and "presentation specifications" (in a web template), are combined (through the template engine) to mass-produce web documents.

This article is part of
the Web Template Systems series.

Main:

A (web) template engine is software that is designed to process web templates and content information to produce output web documents. It runs in the context of a template system.

Contents

[edit] Specific types of template engines

Template engine is ordinarily included as a part of a web template system or application framework, and may be used also as preprocessor, filter, or template processor. Currently, template processing software is most frequently used in the context of development for the web.

XSLT is a template processing model designed by W3C. It is designed primarily for transformations on XML data (into web documents or other output).

Programming languages such as Perl, Ruby, C, and Java support template processing either natively, or through add-on libraries and modules. JavaServer Pages (JSP), PHP, and Active Server Pages (ASP with VBScript, JScript or other languages) are examples, themselves, of web template engines.

[edit] Typical Features

Template engines typically include features common to most high-level programming languages, with an emphasis on features for processing plain text.

Such features include:

[edit] A web template example

The accompanying illustration depicts a simplified processing model for a typical web template engine. The template engine produces a web page by processing the web template source file along with data from a relational database. The template engine replaces variables with specific values. In the illustration, substitution of $X by the database content (in page 01 "Mother", on page 02 "World").

A web template might look like this:

<html>
   <h1>Hello {$X}</h1>
</html>

With additional template source code ...

templateAssign ('X', 'World');

... or, when specifying the relational database context:

$data[01]='Mother';  $data[02]='World';
templateAssign('X', $data[$i]);

[edit] Benefits of using template engines

  • encourages organization of source code into operationally-distinct layers (see e.g., MVC)
  • enhances productivity by reducing unnecessary reproduction of effort
  • enhances teamwork by allowing separation of work based on skill-set (e.g., artistic vs. technical)

[edit] Comparison of template engines

The following table lists the various template engines discussed on Wikipedia and a brief rundown of their features. The content here is a work-in-progress.

Engine (Implementation) Languages License Platform Variables Functions Includes Conditional Inclusion Looping Evaluation (Language) Assignment Errors & Exceptions
StringTemplate Java (native), Python, C# open-source? Cross-Platform Yes No Yes Yes Yes No No No
ASP.net (Microsoft) C#, VB.net Proprietary Microsoft Windows Yes Yes Yes Yes Yes Yes Yes Yes
ASP.net (Mono) C# GNU LGPL Cross-Platform Yes Yes Yes Yes Yes Yes Yes Yes
Apache Velocity Java Apache License Cross-Platform Yes Yes Yes Yes Yes Yes Yes Yes
Beilpuz PHP 5 GNU LGPL Cross-Platform Yes Yes Yes Yes Yes No Yes Yes
CheetahTemplate Python MIT License Cross-Platform Yes Yes Yes Yes Yes Yes Yes Yes
Chip Template Engine PHP, Perl open-source? Cross-Platform Yes Yes Yes Yes Yes No Yes No
CTPP C, C++, Perl, PHP, Python BSD-like Cross-Platform Yes Yes Yes Yes Yes No No Yes
Dwoo PHP 5 GNU LGPL Cross-Platform Yes Yes Yes Yes Yes Yes (PHP) Yes Yes
Dylan Server Pages Dylan language unknown unknown Yes Yes Yes Yes No? No No No
eRuby Ruby open-source? Cross-Platform Yes Yes Yes Yes Yes Yes Yes Yes
Evoque Templating Python AFL v3.0 Cross-Platform Yes Yes Yes Yes Yes Yes (Python) No Yes
FreeMarker Java BSD-like Cross-Platform Yes Yes Yes Yes Yes Yes Yes Yes
Genshi (templating language) Python BSD-like Cross-Platform Yes Yes Yes Yes Yes Yes (Python) Yes Yes
GvTags Groovy Apache License Cross-Platform Yes Yes Yes Yes Yes Yes (Groovy) Yes No
Haml Ruby, PHP (WIP) MIT License Cross-Platform Yes Yes Yes Yes Yes Yes (Ruby) Yes Yes
JSP Weaver Java Proprietary Cross-Platform Yes Yes Yes Yes Yes Yes Yes Yes
Jasper framework Perl, PHP, C#, Java open-source? Cross-Platform Yes No No No No No No No
JavaServer Pages Java Proprietary Cross-Platform Yes Yes Yes Yes Yes Yes Yes Yes
Jinja (Template engine) Python BSD-like Cross-Platform Yes Yes Yes Yes Yes Yes (Python) Yes No
Kid (templating language) Python open-source? Cross-Platform Yes Yes Yes Yes Yes Yes (Python) Yes Yes
Template Blocks PHP 5 GNU GPL Cross-Platform Yes Yes Yes Yes Yes Yes (PHP) Yes Yes?
Open Power Template PHP 5 GNU LGPL Cross-Platform Yes Yes Yes Yes Yes Yes (PHP) No No
Outline PHP 5 open-source Cross-Platform Yes Yes Yes Yes Yes Yes (PHP) Yes Yes?
PHAML PHP MIT License Cross-Platform Yes Yes Yes Yes Yes Yes (PHP) Yes Yes?
Smarty PHP GNU LGPL Cross-Platform Yes Yes Yes Yes Yes Yes (PHP) Yes Yes?
TinyButStrong PHP open-source? Cross-Platform Yes No Yes No Yes No No No
Vemplator PHP MIT Cross-Platform Yes Yes Yes Yes Yes Yes (PHP) No No
VlibTemplate PHP open-source? Cross-Platform Yes Yes Yes Yes Yes No No No
Deihro TemplateEngine PHP open-source Cross-Platform Yes Yes indirect No No No No No
WebMacro Java open-source? Cross-Platform Yes Yes Yes Yes Yes Yes Yes Yes

[edit] See also

[edit] External links

Other template engines on template systems:

Template engine usage:

Languages