Access Information Through World Wide Web

The World Wide Web is designed to be easy to attach to. Not just by using Mosaic, Lynx, or Netscape to read other people's pages, but also by publishing your own information. Eric Kasten tells you how to start.
The Default Welcome Document

You will probably want to have a default document that will be displayed when a client accesses your server without specifying a particular document. For instance, a client might connect to your server using a URL of the form http://wwwhost.my.domain.name/. If there is no default welcome document, a file listing of the directory as specified by the Pass directive will be displayed. A client may then access any documents in this directory with the correct permissions. Also, keep in mind that if a document is in the htdocs directory, a client can access it by explicitly naming that file in a URL. Only documents which you want made public should be here.

To create a default welcome page for your server, you need simply create a welcome document in the directory /usr/local/WWW/htdocs using one of the file names you specified in the server configuration file with a Welcome directive. To set up a simple default welcome document create the file /usr/local/WWW/htdocs/Welcome.html containing the following text and set the file permissions to be world readable (chmod a+r):

<TITLE>Welcome!</TITLE>
Welcome to my WWW server!

This will display a document with the title Welcome! and a simple welcome message displayed in the body. Later, you will probably want to add more interesting information to this file, along with links to other documents that your server provides.

Testing and Startup

Now the server is ready for an initial test run. You will first want to start up the server in verbose mode from a terminal connection so that you can check for any configuration errors. From a terminal, enter the following:

/usr/local/WWW/httpd -v -r /usr/local/WWW/config/cern_httpd.conf &

The -v flag indicates that server should run in verbose mode, and the -r flag specifies the server configuration file. The server will print a number of initialization messages and messages about any configuration errors it encounters as it starts. Check these messages for errors or discrepancies. Once the server has completed its start-up processing, you can use your favorite WWW browser to connect to it using an URL of the form:

http://wwwhost.my.domain.name/

If all goes well, you should see the message from the default welcome document. Be sure to examine the output of the server for any errors, and correct them as necessary.

The server can be started from one of your rc scripts (probably rc.local or rc.inet2) when the system is booted. It should be started after the network is initialized. A good place to start the daemon is in the same rc script used to start sendmail or inetd. The following entry can be used to start the httpd server daemon and to warn you if it cannot be started:

# Start the CERN httpd server
if [ -x /usr/local/WWW/httpd ]; then
          echo -n ", httpd"
          /usr/local/WWW/httpd -r /usr/local/WWW/config/cern_httpd.conf &
else
          echo
          echo "=================="
          echo " httpd not found. "
          echo "=================="
fi

This is a standalone startup of the daemon. You can also start the server using inetd, but you will get better response from a standalone startup. Proper configuration of inetd is outside of the scope of this article. If you wish to use inetd, please refer to the man pages and documentation on inetd and the relevant section of CERN's documentation available at www.w3.org/hypertext/WWW/Daemon/User/Installation/Inetd.html. inetd was also documented in the System Administration column in issue 12 of Linux Journal.

Controlling the Daemon

The httpd daemon accepts various types of signals. Two of these are most notable. A KILL signal will cause the daemon to terminate, and can be issued with the following command:

kill -KILL `cat /usr/local/WWW/httpd-pid`

or

killall -KILL httpd

Sometimes you may want to reconfigure the daemon without shutting it down. This can be done by changing the configuration files then issuing a HUP signal to the daemon as follows:

kill -HUP `cat /usr/local/WWW/httpd-pid`

or

killall -HUP httpd

As always, be sure to check the error log for any possible configuration errors.

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