First, we write template files like the ones above for all the common elements of our pages, and the overall page layout. We remove all the common elements from our page files, leaving just the page content. Then we add three lines of PHP to each page, like this:

This has largely addressed the problems. There are just three lines of PHP in the file, none of which contain any template-related code and are thus never likely to need changing. And the HTML is outside the PHP tags and thus does not need special characters escaping. We can easily add these three lines of PHP to all our static HTML pages.

The require function includes a PHP file which contains all the necessary template-related PHP code. The pageStart function sets up the template object (and sets a page title), and the pageFinish function parses the template and generates the output for the browser.

How is this done? Why does the HTML in this file not get sent to the browser before the pageFinish function gets called? The answer is a new feature introduced in PHP4 that allows output destined for the browser to be captured in a buffer. A look at the prepend.php file shows how this works:

The pageStart function instantiates a template and sets it up, then turns on output buffering. Now, all HTML from the page itself is captured in the buffer. The pageFinish function extracts the buffered content and uses it to define the template object's content before parsing the templates and outputting the finished page.

That's it. Write template files containing HTML fragments to define your site's common elements. Delete all the common page layout stuff from all your pages and replace with three lines of PHP you will never need to change. Put the FastTemplate class file and the prepend PHP file in your include path. Now you have a web site where the page layout is centrally controlled, enhancing reliability and maintainability and making site-wide changes easy.

Zipped archive of the files in this article, including a working example site and with more comments in the code than shown here.

The FastTemplate class can be found at http://www.thewebmasters.net/. The latest version is 1.1.0 and there is a small patch to apply to ensure correct operation with PHP4. Alternatively, the zipped archive above includes the class already patched.

The functions in prepend.php are based on ones (without output buffering) described in "Professional PHP Programming" by Harish Rawat, et al.

-- Matthew