php.MVC The Model View Controller (MVC) Framework for PHP Web Applications

In the beginning there was the simple Web page. Web sites were built using basic HTML with content coded directly in the pages. Things were simple then.

As the Web evolved and became an important information and entertainment medium, more and more Web sites became Web applications with more sophisticated presentation and user interaction requirements.

To cope with this additional complexity, techniques were developed to apply templating and modular design concepts to Web page construction. Most Web development environments now have tools available to aid in the development of sites using templating and modular construction techniques.

The PHP Web environment has many such tools to choose from, some of which are listed in the resources section. This guide uses the PhpTAL templating system as a Plug-in to the php.MVC Web application framework.

PhpTAL is a port of the successful Zope templating engine. Using PhpTAL we will build some Web application pages, starting with a simple page to introduce basic templating techniques and dynamic data. We will then quickly move on to more complex page layouts using page components to build the pages with common sections like headers, footers, navigation bars, contents etc.

Although we are focused on using PhpTAL, most of the page layout techniques we will use in this guide should be easily adapted for use with the various other PHP templating systems.

There is currently much discussion on the pros and cons of the various templating techniques. The benefits and costs of these approaches to page design is a research topic in itself and is beyond the scope of this guide.

Prerequisites:

To get the most from this guide you should at least be familiar with basic HTML page construction and style sheet (CSS) usage. It would probably be a good idea to have the PhpTAL documentation at hand when working through the examples. See the reference section for links to sources of online documentation.

A working knowledge of how php.MVC applications are setup and operate will be helpful, as we will not cover the setup and operation of a php.MVC application in much detail in this guide. Please refer to the other guides and examples as required.

How PhpTAL Page Templates Work:

Web page templating systems allow the developer to separate her business logic (a report generating class and methods, for example) from the actual HTML pages. The programmers can now focus on the applications business classes, while leaving the designers to concentrate on page layout and design issues.

As stated above PhpTAL is a port of the Zope templating engine. PhpTAL uses the Template Attribute Language (TAL). TAL is defined as attributes to standard HTML tags, for example:

 <title tal:content="title">Page Title</title>

This statement specifies that the contents of the title page tag be replaced with the value we assign to the TAL variable


"title"

, for example "Welcome To My Site". So the result after processing could look something like:

 <title>Welcome To My Site</title>

Pages containing TAL attributes are still valid XML documents. It is now possible for the page designer to open the page in an WYSIWYG editor or Web browser, and the structure of the page will be unchanged. In our code fragment above, the text Page Title will act as a place holder for the actual dynamic text in the title tag.

We will see how to set the TAL template variables in our classes in a later section of the guide.

PhpTAL supports the common template variable replacement techniques and other sudo-programming operations such as loops, as found in most popular template engines. Additionally PhpTAL implements Macros, or the Macro Extension for TAL (METAL). PhpTAL Macros provide a more sophisticated method of building documents from sections of other pages.

By using these templating features we can greatly reduce the coupling of our business code to the presentation, more easily create a common look-and-feel design, and eliminate much repetition and maintenance associated with modern Web applications.

Please refer to the The Zope Book: Appendix C, "Zope Page Templates Reference", for more detailed information on TAL. See the reference section for links to the relevant resources.

Download the Example App:

The example application can be downloaded here:
adv-page-layout-tal.tgz
adv-page-layout-tal.zip

Unpack the archive to a Web accessible directory on your Web server. Open Main.php in an editor and set the application path and the phpmvc library path to reflect your installation. Note: These paths are absolute paths, not URL type paths. The path statements should look something like:

 /* ---------- Application Paths ---------- */
 // Set php.MVC library root directory
 $appServerRootDir = 'C:/WWW/phpmvc-base';            // no trailing slash
 
 // Set the application path
 $moduleRootDir = 'C:/WWW/phpmvc-test/PageLayoutTAL'; // no trailing slash
 /* ---------- Application Paths ---------- */

To run the example application, point your browser to index.html file.

For more information on setting up php.MCV applications, please refer to the other resources available in the
User Guides directory.

The Troubleshooting Guide to php.MVC could be useful to diagnose any problems.

Resources:

PHPTAL Template engine

PHPTAL - PHP Template Attribute Language, by Laurent Bedubourg

Zope Page Template Documentation:

Compare and Contrast:

Other Resources:



Copyright © 2006 John C. Wildenauer. All rights reserved.