Common gateway interface (CGI) is the standard for interfacing external programs with information servers on the World Wide Web. Essentially, it provides a standard protocol that is used by web servers to execute programs that run on a server and generate web pages. These programs are known as CGI scripts, and the details of how a script is executed by a server are determined by the server itself.
Common gateway interface refers to a set of rules that apply to running scripts and programs across a server on the Internet. It specifies what type of information is communicated between a web server and web browsers, and how that information is transmitted. It is the standard for interfacing eternal programs with information servers on the web.
Common gateway interface is differentiated from a plain HTML document because a plain HTML document is static, whereas a common gateway interface is executed in real-time in order to output a tremendous amount of information. In other words, a program that utilizes common gateway interface is executable, while the plain HTML document remains a constant text file that cannot be changed. Common gateway interface gathers information from users across the web and customizes pages to their specific needs. Though there are more advanced ways to execute the same type of actions, common gateway interface is much more versatile. This is why, over time, it has become the generalized way to refer to any program that is run on a web-based server and interacts with a browser.
A good example of common gateway interface is as follows:
If you wanted to make it possible for people around the globe to query a database that you have created, you could develop an executable common gateway interface script that would be able to send information directly to the database engine, which would allow you to receive results and place them in a user’s web browser. That user would not be able to directly access the database without type of gateway providing access. The link between the database and the user is referred to as the “gateway”, which is exactly where the common gateway interface standard originated from.
The significance of common gateway interface is directly related to the fact that it offers flexibility and versatility which have made is the standard for running executable files from web-based servers. This makes real interactivity possible in a myriad of ways across websites.
For instance, common gateway interface scripts can employ the following types of features:
Though it might seem like a complex process, the manner in which a common gateway interface script works is really rather simple and straightforward. Essentially, the process involves the following:
Though the applications that common gateway interface can execute can be implemented in other ways, they aren’t as versatile. Common gateway interface truly is the standard, and most programmers would simply rather make improvements to their old scripts so that they can be used in new ways than start from the bare bones.
Despite the benefits, there are some disadvantages associated with common gateway interface. For example, a lot of the newer languages that have been developed are slow. Additionally, there are some significant security issues that have been linked to common gateway interface.