How To Best Utilize Python CGI In Day To Day Coding?

How To Best Utilize Python CGI In Day To Day Coding?

Dec 16, 2020, 9:13:50 AM Tech and Science

According to python experts, one of the most talked-about features of the Python programming framework is the Python CGI and so let's talk more about the Python CGI in this blog, its uses, and how it can be used in day-to-day coding.

Blog Contents

  1. What is Python CGI?
  2. Working with CGI
  3. Functions in Python CGI
  4. Advantages of Python CGI
  5. Disadvantages of Python CGI
  6. Conclusion

In this blog, let’s know about how you can utilize Python CGI. Let’s go!

What is Python CGI?

CGI or Common Gateway Interface is an industry-approved acronym for a set method used to describe how information is shared between the web server and a custom script. As of date, the NCSA legally manages the CGI files.

CGI is a way of writing a program that has the ability to share data through a web server running on another web server, as stated in an earlier paragraph. One of the most important things to remember is that CGI programs are written to dynamically create web pages that not only take input from users but also view the output at the same time while writing a CGI program on the Python interface.

Working with CGI

The CGI uses external script files to manage certain requests when a request is made to the web server by the client-server. It is possible to write these files in any language. The primary aim of these script files is to quickly and more easily extract the data from the database. These scripts translate the retrieved data into an HTML format, which sends the data to the HTML formatted page on these web servers. 

The FieldStorage class can be used to work with the submitted data for the form. First of all, if the form holds non-ASCII characters, the encoding keyword parameter for the encoding defined for the document is set. This can be found in the <META tag in the HTML document's <HEAD> section. Alternatively, in the Content-type header, it can be found. FieldStorage reads the contents of the form from the normal input or the environment.

A FieldStorage instance can also be indexed like a Python dictionary. This makes it possible to check membership with the in' operator. Then the key() method and len() function can also be called. Notice that it ignores fields with string values that are void. To maintain them, at the time of creating a FieldStorage instance, a true value can be given for the optional keyword parameter,i.e.,keep_blank_values.

Consider the situation when an uploaded file is denoted by a field. When the value is accessed using the 'value' attribute or the getvalue() process, the whole file in the memory is read as bytes. Either the 'filename' attribute or the 'file' attribute can be tested in order to test an uploaded file.

Functions in Python CGI

You can use the following functions for more control over your CGI programming in Python:

a. cgi.parse(fp=None, environ=os.environ, keep_blank_values=False, strict_parsing=False)

This parses the query in the environment. We may also do it from a file for which sys.stdin is the default.

b. cgi.parse_qs(qs, keep_blank_values=False, strict_parsing=False)

Python retains it for backward-compatibility, although this is discontinued. But instead we can use urllib.parse.parse qs().

c. cgi.parse_qsl(qs, keep_blank_values=False, strict_parsing=False)

This is also outdated, and is retained for backwards-compatibility. Urllib.parse.parse qsl() can be used instead.

d. cgi.parse_multipart(fp,pdict)

This function will parse the multipart/form-data style input for file uploads. The first argument takes the input file, and the second argument takes the dictionary with the Content-Type header containing other parameters.

e. cgi.parse_header(string)

A MIME header is passed by parse header() into a key value and into a parameters dictionary.

f. cgi.test()

This is a CGI script test feature, and we will use it as the main programme. Minimal HTTP headers and formats will be written.

g. cgi.print_environ()

This formats the HTML shell environment.

h. cgi.print_form(form)

This feature formats an HTML type.

i. cgi.print_directory()

The current directory in HTML will be formatted.

j. cgi.print_environ_usage()

This will print a list in HTML of all useful environment variables.

k. cgi.escape(s, quote=False)

Escape() will transform '<', '>', and '&' characters to HTML-safe sequences in the string 's'. 

Advantages of Python CGI

Some advantages of CGI are discussed:

1. They are versatile and can operate on almost every operating system and the webserver.

2. They are independent of language.

3. They are very scalable programs, which means that they can perform tasks that are both simple and complex.

4.In web applications, CGIs improve complex communication.

5 They also help to make companies more profitable by reducing the expense of production and maintenance.

Disadvantages of Python CGI

Some CGI drawbacks are as follows:

1. Every time the program is started, the interpreter has to analyze a CGI script, which causes a lot of traffic as there are so many requests from the client-server side.

2 The programming and creation of CGI programs are very difficult and unclear.

3 Server protection can be breached by CGI programs because most of them are free and readily accessible, making them very vulnerable.


Python CGI has made coding easy and fun. In this blog, an attempt was made to show how Python CGI can be used in day-to-day coding. Get a python certification, enroll for a Python Crash course, and become a python expert.

Published by Ramakant Sharma

Written by Ramakant Sharma


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