Python CGI Programming

Python is one of the most versatile programming languages available in the market today. The main reason for popularity of Python is the great number of features it brings to the table as well as its versatility across multiple platforms. One of the features of the Python programming system that we get asked about most is the Python.Let's know more about Python CGI, its uses and how you can implement it in your day to day coding.CGI or Common Gateway Interface is the industry accepted acronym for a set method that is used to define how information is exchanged between the web server and a custom script. As of date, the CGI scripts are officially maintained by the NCSA. 

As mentioned in an earlier paragraph, CGI is a manner of writing a program that has the ability to exchange data through a web server that is running on another web server. One of the most important things to note, while writing a CGI program on the Python interface is that CGI programs are written to dynamically generate web pages that not only take input from users but also display the output at the same time. 

Structure of a Python CGI Program 

let us take a closer look at the structure of the same.

1. The output of a CGI script written in Python must contain two sections separated by a blank line. 
2. The first section will contain the headers that describe and the second section will contain the kind of data that will be used during the execution of the script.

In order to use the CGI module in Python, you first need to import it into the Python IDLE. The syntax to do the same is as follows.

 import cgitb

cgitb.enable()

When scripting a CGI program in Python take note of the following commonly used syntaxes. 

HTML

1. Content or Type: text/html
2. Location: URL
3. Expires: Date
4. Content Length: N
5. Set Cookie: String

Along with the HTMl syntaxes shared above, you also need to make a note about the commonly used CGI environment variables. 

1. CONTENT_TYPE: This is used to describe data and type of the content. 
2. CONTENT_LENGTH: This is mainly used in Post to define the length of a query or information.
3. HTTP_COOKIE: If in a certain situation, the user has set a cookie, then this is used to return the same.
4. HTTP_USER_AGENT: If you need to view the type of browser the user is currently using, then this variable will be used. 
5. REMOTE_HOST: This is used to define the host name of the visitor.
6. PATH_INFO: This is used to define the path of a CGI script.
7. REMOTE_ADDR: If you need to define the IP address of the visitor, then you can make use of this variable. 
8. REQUEST_METHOD: This is used to make a request either via POST or GET.