CGI and Web Programming Revolution

Common Gateway Interface (CGI) revolutionized web programming by enabling web servers to generate dynamic content. Before CGI, web servers primarily delivered static HTML pages. CGI provided a standard method for external programs (scripts written in languages like Perl, C, Python, or shell scripts) to interact with HTTP servers. This allowed web applications to process user input, access databases, and produce HTML output tailored to specific requests, rather than serving pre-existing files.

For instance, CGI made it possible to create:

• Online forms that could process user submissions (e.g., guestbooks, feedback forms).
• Search engines that queried databases and displayed results dynamically.
• E-commerce sites that managed shopping carts and processed transactions.

This capability transformed the web from a collection of static documents into an interactive platform, laying the groundwork for complex web applications. However, this also introduced new security challenges, as vulnerabilities in CGI scripts could expose the server to attacks. More on this can be found in Guide to Computer Network Security by Joseph Migga Kizza, specifically on the impact of scripting technologies on web security, and in resources like CERT® Advisory CA-2000–02 Malicious HTML Tags Embedded in Client Web Requests which highlights potential issues with server-side processing.