As suggested in part 1 of this series of tutorials, a PHP based template system can use PHP commands or keywords. Here we'll tackle the same task as before but this time we'll use keywords instead of PHP functions. The tricky part about this is that we have to "parse" the template instead of simply including it in the handler script!
This system is much more complex and is really only suggested when you want someone other than yourself to create templates. The first thing you should do when creating a template based website using PHP with keywords is to decide on the exact method of keyword implementation! You have to make the keywords easy enough for anyone to use but unique enough to keep the script from confusing regular content or words with keywords. Some little used non-alphanumeric character and/or all capital letters is one method while a prfix and underscore is another. For example:
{KEYWORD1}
{KEYWORD2}
or
[temp_menu]
[temp_header]
[temp_footer]
or
%_MY_MENU_%
%_MY_FOOTER_%
%_MY_HEADER_%

By making the keyword syntax rules early, you can avoid complications later.

The only files that we have to change for the keyword system are template.php and the handler (index.php, content1.php) files. The other files will remain unchanged and copies of all can be found below:

Simple HTML Template Sample 1 - Keywords

Notice that we have replaced all of the PHP echo commands with keywords in curly brackets {}.
Since this file doesn't have any PHP in it, you could give it a .txt, .html, or any other file extrension.

Simple main_menu.php Sample 1 - Keywords

Notice that this file is unchanged from part 1.

Simple header.php Sample 1 - Keywords

Notice that this file is unchanged from part 1.

Simple footer.php Sample 1 - Keywords

Notice that this file is unchanged from part 1.

Simple index.php Sample 1 - Keywords

This file has had extensive changes made to it.

Simple content1.php Sample 1 - Keywords

This file has had extensive changes made to it.

These files will output the following:

Until now, the PHP used has been pretty basic but the use of functions like file_get_contents, array, and preg_replace makes the code much more complicated and the use of these functions need to be discussed.

file_get_contents is used read the contnets of a file without the burden of using the file system and also allows for reading remote file contents. For example, using file_get_contents you can read any webpage on the Internet. Doing this, you will actually see the page the same way your web browser sees it, in raw HTML. So if you read a remote PHP file, you will only get it's output, not the actual source of the script. Here the function is used to assign the contents of the template.php file to the variable $template.

array is a commonly used function in PHP. You can think of an array like an multi-part variable. It will allow you to store many values in a single variable. Along with this function is several related functions which can help you sort the values in an array among other things. In this situation, we use 2 arrays for the search and replace system needed for the keywords. The 2 arrays are related to each other so the order of the first array must match the order of the second array. Some functions can cycle through the values in an array and apply it's command on each. Which brings us to the last function.

preg_replace is a replace function that uses regular expressions to identify a pattern in the string. A regular expressioncan be very simple or very complex depending on what you want to match. If you know exactly what you are looking for and that it will nevery vary in any way, the regular expression will be very simple but if you are looking for something that may vary greatly, the regulare expression will be very complex. A simple regular expression would be to find a specific word in a paragraph but a complex expression would be used to find every link on any website! Since the link will vary in position, title, url, extra parameters, and author style; you have to teach the script how to find a link. The preg_replace will look for the search term, replace it with the replace term, based on the string in the third argument. In our situation, the string is represented by the variable $template and the search and repace terms are represented by their repected arrays. This method can also be used to rewrite all of your links to something cleaner or filter out dirty words!

With a little planning and some hard work, you could convert your entire HTML website into a template driven PHP system.

In the next part, we'll look into data files and query string urls which will convert this static system into an generated on the fly dynamic system.

Enjoy your new template driven PHP site.

{mos_sb_discuss:4}