Getting PHP

The first step to creating your own interactive web pages is to get access to a web server that runs PHP. In fact, your Internet Service Provider (ISP) probably supports PHP already. You can find out by asking your ISP's support staff, or you can test for PHP yourself in one of two ways.

First, if you can open a command prompt by connecting to your web server using a Telnet, SSH, or SSH2 application (don't worry if you don't know what these applications areyou won't need them in this book), you can try typing php -v at the command line (we'll use a % sign for a generic command prompt in this book). If you have PHP installed, you'll see something like this:

 %php -v PHP 5.0.0 (cli) (built: Jul 13 2004 21:39:58) Copyright (c) 1997-2004 The PHP Group Zend Engine v2.0.0, Copyright (c) 1998-2004 Zend Technologies 

The other way to determine whether you have PHP installed is by trying out an actual PHP script. To do that, take a look at the section "Creating Your First PHP Script" in this chapter. If that script works, you've got PHP installed, and you're all set.

NOTE

If you want a list of ISPs that already run PHP, take a look at www.php.net/links.php#hosts.

Installing PHP Locally

It's a good idea to install PHP on your own computer so that you can test your PHP scripts as you develop them. This way, you won't have to take the time to upload your PHP scripts to your ISP, check them by downloading them in your browser, make changes, and then start the whole cycle again. If you develop your PHP scripts locally, you can get things running a lot faster, but you'll need to install PHP on your own machine.

Some operating systems, such as Linux and many versions of Unix, now come with PHP installed by default. In others, such as Windows and Mac OSX, you'll have to download and install PHP yourself. The first step is to check if you already have PHP available locallytry the php -v command at the command prompt (for example, in Windows, open a DOS window and type php -v). If it works, you're all set.

If you don't have PHP already installed, you can install it yourself. Prebuilt "binary" versions are available for download and immediate installation for a number of operating systems: Windows, Mac OSX, Novell NetWare, OS/2, RISC OS, SGI IRIX 6.5.x, and AS/400. You can find the binary installation package for Windows at http://www.php.net/downloads.php, along with links to the binaries for the other operating systems mentioned.

NOTE

Binaries are no longer distributed for Linux and Unix because PHP is usually pre-installed. If you want, you can build your own PHP installation from source code. Go to http://www.php.net/downloads.php to get the source code for PHP.

You can find the installation instructions for PHP in the PHP documentation, which is online at http://www.php.net/docs.php (you can download the complete PHP documentation from http://www.php.net/download-docs.php). You can also find installation instructions in an installation file (named, for example, install.txt) when you uncompress the PHP download. Because the instructions change every time PHP changes, and because there are so many possible variations of operating systems and web servers, you should read the current installation instructions and use them. Listing all the instructions here would take 20 pages, and they'd be obsolete by the time you read them.

Briefly, here's how things might work in Windows XP (all this can be found in full detail in the downloadable installation instructions). You first need a web server, such as the Apache web server or Microsoft's Internet Information Server (IIS). You can get a Windows installer file for Apache (apache_2.0.52-win32-x86-no_ssl.msi) at http://httpd.apache.org/ download.cgi; when you download and double-click this file, it installs Apache. Or you can install IIS in Windows XP by using the Add/Remove Programs icon in the Control Panel, clicking the Add/Remove Windows Components button, and then selecting IIS.

PHP can be installed in two different ways for Windows, and you can download what you need for both methods from http://www.php.net/downloads.php. There's a Windows installer executable file, php-5.0.x-installer.exe, with basic PHP support (which includes standard PHP but no external extensions). This installer will automatically configure servers such as IIS, PWS, and Xitami, and it has instructions for manual configuration of other servers such as Apache.

The other installation technique uses a .zip file, php-5.0.x-Win32.zip, which contains the full PHP installation and allows for external extensions (this option is better if you want to do everything covered in this book). Download and unzip this file; you'll find all the installation instructions included. Depending on your operating system, you typically copy php.exe to the directory from which you intend to run it, for example.

The next step is to connect your PHP installation to your web server. If you've unzipped the PHP .zip file in Windows XP and you're using Apache, you should edit the Apache http.conf file, following the directions in the installation instructions. If you're using IIS, you configure IIS with its management console (select Start > Settings > Control Panel > Administrative Tools > Internet Services Manager in Windows XP), also following the directions in the installation instructions. For the full details, see the instructions, which take you through everything step by step.