Configuring Apache: The First Steps (Apache: The Definitive Guide, 3rd Edition)

After the installation described in Chapter 1, you now have a shiny bright apache/httpd, and you're ready for anything. For our next step, we will be creating a number of demonstration web sites.

2.1. What's Behind an Apache Web Site?

It might be a good idea to get a firm idea of what, in the Apache business, a web site is: it is a directory somewhere on the server, say, /usr/www/APACHE3/site.for_instance. It usually contains at least four subdirectories. The first three are essential:

conf

In our standard installation, there will also be a file go in the site directory, which contains a script for starting Apache.

Nothing happens until you start Apache. In this example, you do it from the command line. If your computer experience so far has been entirely with Windows or other Graphical User Interfaces (GUIs), you may find the command line rather stark and intimidating to begin with. However, it offers a great deal of flexibility and something which is often impossible through a GUI: the ability to write scripts (Unix) or batch files (Win32) to automate the executables you want to run and the inputs they need, as we shall see later.

2.1.1. Running Apache from the Command Line

If the conf subdirectory is not in the default location (and it usually isn't), you need a flag that tells Apache where it is.

httpd -d /usr/www/APACHE3/site.for_instance -f...

apache -d c:/usr/www/APACHE3/site.for_instance

Notice that the executable names are different under Win32 and Unix. The Apache Group decided to make this change, despite the difficulties it causes for documentation, because "httpd" is not a particularly sensible name for a specific web server and, indeed, is used by other web servers. However, it was felt that the name change would cause too many backward-compatibility issues on Unix, and so the new name is implemented only on Win32.

Also note that the Win32 version still uses forward slashes rather than backslashes. This is because Apache internally uses forward slashes on all platforms; therefore, you should never use a backslash in an Apache Config file, regardless of the operating system.

Once you start the executable, Apache runs silently in the background, waiting for a client's request to arrive on a port to which it is listening. When a request arrives, Apache either does its thing or fouls up and makes a note in the log file.

What we call "a site" here may appear to the outside world as hundred of sites, because the Config file can invoke many virtual hosts.

When you are tired of the whole Web business, you kill Apache (see Section 2.3, later in this chapter), and the computer reverts to being a doorstop.

Various issues arise in the course of implementing this simple scheme, and the rest of this book is an attempt to deal with some of them. As we pointed out in the preface, running a web site can involve many questions far outside the scope of this book. All we deal with here is how to make Apache do what you want. We often have to leave the questions of what you want to do and whyyou might want to do it to a higher tribunal.

httpd (or apache) takes the following flags. (This is information you can evoke by running httpd -h):

-Usage: httpd.20 [-D name] [-d directory] [-f file]
                [-C "directive"] [-c "directive"]
                [-v] [-V] [-h] [-l] [-L] [-t] [-T]
Options:
  -D name           : define a name for use in <IfDefine name> directives
  -d directory      : specify an alternate initial ServerRoot
  -f file           : specify an alternate ServerConfigFile
  -C "directive"    : process directive before reading config files
  -c "directive"    : process directive after  reading config files
  -v                : show version number
  -V                : show compile settings
  -h                : list available command line options (this page)
  -l                : list compiled in modules
  -L                : list available configuration directives
  -t -D DUMP_VHOSTS : show parsed settings (currently only vhost settings)
  -t                : run syntax check for config files (with docroot check)
  -T                : run syntax check for config files (without docroot check)

  -i                : Installs Apache as an NT service.
   -u                   : Uninstalls Apache as an NT service.
   -s                   : Under NT, prevents Apache registering itself as an NT service. If you
                          are running under Win95 this flag does not seem essential, but it
                          would be advisable to include it anyway. This flag should be used
                          when starting Apache from the command line, but it is easy to forget
                          because nothing goes wrong if you leave it out. The main advantage is
                          a faster startup (omitting it causes a 30- second delay).
 -k shutdown|restart : Run on another console window, apache -k shutdown stops Apache
                      gracefully, and apache -k restart stops it and restarts it
                      gracefully.

The Apache Group seems to put in extra flags quite often, so it is worth experimenting with apache -? (or httpd -?) to see what you get.

Chapter 2. Configuring Apache: The First Steps

Contents:

2.1. What's Behind an Apache Web Site?

2.1.1. Running Apache from the Command Line