PHP

When a project gets complicated then so to can the build.xml file associated with it. You might find it necessary to have multiple different filesets, each of which do something different, but all of which have the same core files that they use. Multiple filesets are useful if you want to create a version of your project with all of the testing files in place so that it can be tested by external developers.

Creating multiple filesets can create problems, one of which is maintenance. Confusion can also occur even if you have a single large fileset where lots of different rules for including and excluding files are defined.

This is where the patternset element comes in. You can create a set of reusable file lists that can be used by more than one fileset, but which also makes maintenance a little easier.

The following snippet shows two patternset elements that show include files and exclude files.

One issue, especially when creating AJAX applications, is that the browser can cache the contents of the page so that when a similar request is made the same content is presented.

To force the browser to present the content you want it to without caching you can add the following headers to your page.

header("HTTP/1.1 202 Accepted");
header("Expires: Mon, 26 Jul 1997 05:00:00 GMT");
header("Last-Modified: " . gmdate("D, d M Y H:i:s") . " GMT");
header("Cache-Control: no-store, no-cache, proxy-revalidate, must-revalidate");
header("Cache-Control: post-check=0, pre-check=0", false);
header("Cache-Control: max-age=10000000, s-maxage=1000000");
header("Pragma: no-cache");

Remember to put this before you print out any content as you will get some nice looking errors otherwise.

Also, I wouldn't put this on every page on the site as it can create an overhead that just isn't needed.

One of the main reasons to use Phing is to create a copy of your project in another directory that you can then use as your distribution copy. Your working directory might contain lots of testing code that is not needed in the final build.

To copy a file from one directory to another using Phing you need to use the copy element. Here is a simple example where a single file is copied from one directory to another.

By default, Phing will look for a file in the current working directory called build.xml when you run it. This document tells Phing what it will be doing during the build. You can change this by using the -f or the -buildfile property of phing and giving the build file as the parameter. The following code makes phing look for a build file called wibble.xml.

phing -f wibble.xml

Assuming that the project is called myProject, then a minimal buildfile would be look like the following.

<!--?xml version="1.0"?-->
<!-- This is a comment -->
 
<project default="main" name="myProject">
  <target name="main">
</target>
</project>

Of course, this doesn't actually do anything at all, so it is utterly useless.

To get Phing you will need to have PEAR installed along with PHP. On a Windows system you can install PEAR by running the go-pear.bat file and running through the prompts there.

To get Phing just run the following commands.

pear channel-discover pear.phing.info
pear install --alldeps phing/phing

You should see the install output looking like this:

downloading phing-current.tgz ...
Starting to download phing-current.tgz (361,527 bytes)
.........................................................................done: 361,527 bytes
install ok: channel://pear.php.net/phing-2.1.1

You can now run Phing by typing the following command:

phing

However, this will automatically try to find a file in the current directory called build.xml, and if it doesn't find this file it will simply state the following before stopping:

Phing is a PHP tool that allows you to build projects. Phing stands for PHing Is Not Gnu make, which is kind of a common coder's joke. It is basically a tool that will take a set of files in multiple directories and create either a zip file or a numerous other things that you might want to do with a project.

Phing itself is a PHP program, so all that is needed to run it is a working copy of PHP. Also, because Phing is part of PEAR it is easy to install, and you don't need to install Apache to run it.

Over the next few posts I will be talking about the sort of things you can do with Phing, how to install it, how to create zip files and how to use variables to simplify things. I will add a list here for each of the posts.

One useful function of any application is to report on any errors that occurred. Zend Framework comes with a nice error controller system that you can activate by creating an ErrorController class.

The following is an ErrorController class that I use. It detects what sort of error occurred and displays a message to the user. It will also email a detailed report of the error to the server admins.

Sometimes it is necessary to turn off PHP parsing for a directory. You might want to give away some source code and therefore don't want to parse that code when the user tries to download it. You could just rename the file to have the extension .phps, which is a PHP source file, but this is an alternate method.

To turn off PHP parsing in a directory just create a .htaccess file with the following content.

php_flag engine off

You can expand on this by adding the following:

AddType text/plain .php

This will force all files to be served as plain text files.

If you are going to use this then be sure that you do not put this in any directory that contains your applications. This will cause your files to be downloadable, including any files with usernames and passwords in.

Zend Framework is a PHP framework, written and maintained by Zend. It is designed to make development of web applications secure, streamlined and reliable.

As with all frameworks there is a learning curve with Zend. However, as soon as you get over this it gets a lot easier. I found that the best way to understand how to program with the Zend Framework is to find some tutorials. Luckily, there are people out there who have created a few Zend tutorials.

Rob Allen has a nice Zend Framework Tutorial which is available at his site. Rob also has a nice tutorial on Zend Framework authentication.

It is sometimes a good idea to find out where users can come from. When PHP is run the $_SERVER superglobal is always available and if the user has clicked on a link and landed on your page then the HTTP_REFERER value will be set. You can retrieve and view it on a test page like this.

if ( isset($_SERVER[ HTTP_REFERER ]) ) {
 echo $_SERVER['HTTP_REFERER'];
}

Of course you might want to do something useful with this. For example, you might want to know what link a user clicked on when they broke your application.