We have used a basic HTTP server setup that can handle CGI requests. Python 3 provides these interfaces in the http.server module. Python 2 had the modules BaseHTTPServer and CGIHTTPserver to offer the same, which were merged in Python into http.server.
The handler is configured to use the /cgi-bin path to launch the CGI scripts. No other path can be used to run the CGI scripts.
The HTML feedback form located on 5_7_send_feedback.html shows a very basic HTML form containing the following code:
<html>
<body>
<form action="/cgi-bin/5_7_get_feedback.py" method="post">
Name: <input type="text" name="Name"> <br />
Comment: <input type="text" name="Comment" />
<input type="submit" value="Submit" />
</form>
</body>
</html>
Note that the form method is POST and action is set to the /cgi-bin/5_7_get_feedback.py file. The contents of this file are as follows:
#!/usr/bin/env python
# Python Network Programming Cookbook, Second Edition -- Chapter - 5
# This program is optimized for Python 2.7.12 and Python 3.5.2.
# It may run on any other version with/without modifications.
#!/usr/bin/python
# Import modules for CGI handling
import cgi
import cgitb
# Create instance of FieldStorage
form = cgi.FieldStorage()
# Get data from fields
name = form.getvalue('Name')
comment = form.getvalue('Comment')
print ("Content-type:text/html
")
print ("<html>")
print ("<head>")
print ("<title>CGI Program Example </title>")
print ("</head>")
print ("<body>")
print ("<h2> %s sends a comment: %s</h2>" % (name, comment))
print ("</body>")
print ("</html>")
In this CGI script, the FieldStorage() method is called from cgilib. This returns a form object to process the HTML form inputs. Two inputs are parsed here (name and comment) using the getvalue() method. Finally, the script acknowledges the user input by echoing a line back saying that the user x has sent a comment.
If you encounter any errors as follows:
127.0.0.1 - - [22/Jun/2017 00:03:51] code 403, message CGI script is not executable ('/cgi-bin/5_7_get_feedback.py')
Make it executable. It can be done by following the following command in Linux:
$ chmod a+x cgi-bin/5_7_get_feedback.py
Once it is made executable, you can rerun the program without any issue.