Testing and Troubleshooting
Testing your installation of PHP is really as simple as writing a
small PHP program and running it. Create a small PHP file to use for tests.
Write the following code in it:
echo "Hey, it worked";
Save the file as test02.php in any folder
within wwwroot (or an appropriate folder if you happen to be running some other
OS/Web server combination than Windows 2000/IIS).
Open the file in your browser. You should see the words "Hey, it
worked" in your browser. If you see "Page cannot be displayed," there's a
problem with your PHP installation or with finding the file, or with the Web
server. If you see something that talks about a parse error, you may have made a
mistake in entering the code. Coding errors are discussed in more detail in the
next few chapters, but in the next section you'll explore some ways you can troubleshoot
your basic installation of PHP.
Did the file you tested work? Or are you reading this section
right now because the file didn't work? Don't worry; it's very common for
problems to occur anytime you try something new, especially when it comes to
computers and programming. In fact, consider yourself lucky if it didn't work
because you'll learn a lot more about PHP and programming from your mistakes
than from your successes.
So let's start at the beginning. Troubleshooting and debugging
comprise the process of identifying problems, deducing possible causes,
logically isolating those causes until you've identified the most likely
culprit, and then trying solutions. The end result is that the problem is fixed
and if you've done a good job, you'll have fixed the problem (in an elegant,
robust way) without causing other problems.
Chapter 5 covers debugging in more detail; for now, though,
let's look at the steps for troubleshooting your installation of PHP:
Check that the Web server is on and running properly. In
Windows 2000, do this by checking Services (Start â‡¨
Programs â‡¨ Administrative Tools â‡¨ Services), specifically Internet Admin Services and World
Wide Web Publishing Service. Just because these are set to Automatic within Services doesn't mean they
are on. Stop and restart them if you need to reassure yourself. You can also
check to make sure the Web server is running on the default Web site in Internet
Services Manager. For Apache on Linux, check the httpd service (you can also
test it by entering http://localhost in your
Place a simple HTML Web page in the wwwroot folder, making
sure that it has .htm or .html
as the extension for the filename (such as test01.htm),
and bring the page up in your browser. Make sure you are using http://localhost/test01.htm to bring up the file, not the
file location (such as D:\inetpub\wwwroot\test01.htm).
If the HTML Web page displays properly, you can be sure your
Web server is functioning. This implies (assuming your PHP page cannot be
displayed) that something is wrong with your PHP installation. Of course, if you
see other messages (such as 404 Page Not Found) you may simply not be finding
the file properly, so you'd need to take a second look at the file name you
chose, the name of your Web folder, and so on.
If you think that something is wrong with your PHP
installation, reexamine the installation process you used, going carefully
through each step, and make sure you placed all the PHP files in the places they
belong. Pay particular attention to the names of Windows and System folders
because these may differ depending upon your installation of Windows or
Check file permissions. File permissions are very important
in Linux systems, and to a lesser degree in Windows 2000 or desktop Windows
operating systems. You should be logged in as root or administrator on Linux and
Windows systems, and should be able to change permissions as necessary to run
scripts from within Web server folders. For external hosting accounts any good
FTP utility can modify file permissions on Linux systems.
It's likely that following these steps will isolate the
problem so that you can fix it.