Evolution of CGI

Since it was first introduced in the early 1990s, the Common Gateway Interface (CGI) has seen tremendous development. The evolving demands of web development and technological advancements have influenced its progress. An overview of its evolution is shown below:

1. Early Year and Origins (1990s)

CGI was developed in response to the early World Wide Web’s demand for dynamic content. The CGI protocol was first established by the NCSA at the University of Illinois in 1993.

Initially, Perl and C were the primary languages used to create CGI scripts. These scripts handled database queries, processed form data, and produced dynamic HTML pages.

2. Performace Obstacles

Due to the fact that each request resulted in a new process, early CGI experienced performance issues. Performance issues resulted from this inefficiency, particularly when there is a lot of web traffic.

3. Server-side Scripting Language (Late 1990s – Early 2000s)

Server-side scripting languages like PHP, Python, Ruby, and Java have become more popular as a solution to performance problems. Compared to CGI, these languages provided more effective techniques to create dynamic web applications.

4. Web Frameworks and Abstraction (2000s – Present)

By offering formal methods for creating dynamic applications, web application frameworks (such as Ruby on Rails, Django, and CGI::Application for Perl) were introduced. The management of HTTP requests and responses was abstracted.

5. FastCGI AND MOD_PERL

Technologies like FastCGI and Mod_Perl were introduced to boost CGI’s performance. FastCGI reduced the overhead of creating processes by enabling CGI programs to run as persistent processes. Similar performance improvements for Perl programs were offered by Mod_Perl.

6. Transition to Web Service and APIs (2000s – Present)

Digital services and APIs have become increasingly prevalent in today’s digital environment. Developers frequently design APIs that feed data to front-end applications rather than creating whole web pages using CGI or server-side scripting.

7. Serverless Computing and Cloud Service (2010s – Present)

Web development has been further changed with the emergence of serverless computing platforms and cloud services (such as AWS Lambda and Azure Functions). As a result of these platforms’ abstraction of server administration, programmers can create and deploy compact, event-driven routines that reply to HTTP requests.

8. Legacy and Influence

Despite its diminished popularity, CGI’s influence can still be seen in the way that modern web programming still separates display from functionality and uses request-response paradigms.

When you click on any of the links on the webpage, your browser contacts the HTTP web server and demands the URL that is, the filename, and the web server passes the URL and looks for the filename, if it finds that file, it will send it back to the browser otherwise sends an indicating message that you have requested a wrong file. Then, the web browser takes a response from the web server and displays either the received file or the error message. However, it is possible to set the HTTP server so that whenever a file in a certain directory is requested, that file is not sent back. Instead, it is executed as a program. And, whenever that program shows any output, it’s sent back to the browser to display. So, this function is called Common Gateway Interface or CGI, and the program scripts are called CGI Scripts. These CGI scripts can be a Python script, PERL script, Shell script, C or C++ program, etc.