World-Wide Web (Often "CGI script") A program running on a
web page, in response to a user's request.
interface between the web server and such programs. The
program can access any data that a normal application program
can, however the facilities available to CGI programs are
usually limited for security.
Although CGI programs can be compiled programs, they are more
script".
Here is a trivial CGI script written in Perl. (It requires
the "CGI" module available from
CPAN).
#!/usr/bin/perl
use CGI qw(:standard);
print header, start_html,
h1("CGI Test"),
"Your IP address is: ", remote_host(),
end_html;
When run it produces an
HTTP header and then a simple HTML
that generated the initial request. If run from a command
prompt it outputs:
Content-Type: text/html
!DOCTYPE HTML PUBLIC "-//IETF//DTD HTML//EN"
HTMLHEADTITLEUntitled Document/TITLE
/HEADBODYH1CGI Test/H1Your IP address is:
localhost/BODY/HTML
The CGI program might be saved as the file "test.cgi" (or
test.pl) in the appropriate directory on a web server,
e.g. "/home/httpd/cgi-bin/".
A user could then type the appropriate
URL,
e.g. http://www.acme.com/cgi-bin/test.cgi, into their
webbrowser to get the program to run and a custom page produced
for them.
Early web servers required all CGI programs to be installed in
one directory called cgi-bin but it is much better to keep
them with the HTML files to which they relate unless they are
truly global to the site. All modern web servers make this
easy to do.
(2000-06-23)