Common Gateway Interface (CGI) is the oldest interface, and is supported by nearly every web server out of the box.
The web server will:
Php is a CGI script.
For instance, you could:
<html>
<head>
<title>PHP Test</title>
</head>
<body>
<?php echo '<p>Hello World</p>'; ?>
</body>
</html>
#!/usr/bin/env python
# -*- coding: UTF-8 -*-
# cgitb enable debugging
# nice call trace vs “Internal Server Error”
import cgitb
cgitb.enable()
print "Content-Type: text/plain;charset=utf-8"
print
print "Hello World!"
The URL takes this specific form where the path is the path to the script
<scheme>://<host>:<port>/<path>?<query>
Environment variables 1) are used to pass data about the http request from the server to the script.
A script will return the response via the standard output file descriptor 2)
The output may have one of the following format:
Programs using CGI to communicate with their web server need to be started by the server for every request. So, every request starts a new process (for python, a new Python interpreter) – which takes some time to start up – thus making the whole interface only usable for low load situations.
FastCGI tries to solve this shortcoming by loading the code into memory and making the script wait for a second request, making the process faster.