Common Gateway Interface is a standard way in which web server can pass a web user’s request to an application form to receive data and send it across to the user. You can request a web page by clicking on a highlighted word or by entering a website address. The server will send you back to the requested page. On the other hand when you fill a form on a web page it is processed by the application program. The web server will pass the information to an application program which will process the data and send a confirmation message. This method of conveying data back and forth is known as common gateway interface.
CGI is part of the Hypertext Transfer Protocol. When you are creating a site and want CGI application to get control it is important that you specify the name of the application in the uniform resource locator or URL which you will code in an HTML file. You can specify this URL in the FORM tags. You can expect consistent transfer of data from the user’s request to the application program and back to the use with the use of common gateway interface. If you are writing the application program you can ensure that it is getting used irrespective of the operating system which is used by the browser.
An important interface
As the interface is consistent a CGI application can be written in different languages. Some popular languages in which CGI applications can be written are Java, C++ and C. A CGI program is designed to transfer data which abides by the CGI specification. A CGI program is one of the most popular ways in which web servers interact dynamically with the web users and ensure that transfer of data takes place seamlessly. HTML pages which contain forms make use of CGI program to process the data once it has been submitted.
Server side solution
CGI is a server side solution as processing of data takes place on a web server. It is important to note that CGI is not the program. It is an interface between the web page and the web server which runs the program. To run pages it is essential that you have access to CGI. Some hosting providers may not allow CGI access on their servers. Make sure that you contact your hosting provider for more information. Most web developers make use of Perl to write CGI scripts.
Use of CGI scripts
CGI scripts are used for several purposes. They are used to resolve form data, put the data in the database and send the data out as an email message. CGI scripts are used for interaction with web readers. CGI is commonly used to automate forms which have programs in the back end to make it work. A CGI script will decode the data and then transfer it. CGI can be written both in scripting and programming language. One common convention is to have a cgi-bin/ directory in the base of the directory tree which treats all the executable files in the directory.
Common uses of CGI
Some common uses of CGI are email forms, blogs and guestbook. In case of guestbook CGI is responsible for accepting data. It ensures that the data is valid and sends an email in the form of an acknowledgement to the writer. In case of email forms CGI scripts format data into an email and send it to the Webmaster. CGI routines also allow visitors to subscribe and unsubscribe from a mailing list. They maintain database of the email address and send acknowledgement to the visitor. A CGI routine refers to anything which understands the CGI standard.
Daniel Lewis stopped by http://bigdropinc.net/ when he was browsing on web design. After visiting the website he understood how creative ideas can be incorporated in web design.