What Is CGI — Perl
CGI (Common Gateway Interface)
The Common Gateway Interface is a standard way for a Web server to pass a Web user’s request to an application program and to receive data back to forward to the user. When the user requests a Web page (for example, by clicking on a highlighted word or entering a Web site address), the server sends back the requested page. However, when a user fills out a form on a Web page and sends it in, it usually needs to be processed by an application program. The Web Server typically passes the form information to a small application program that processes the data and may send back a confirmation message. This method or convention for passing data back and forth between the server and the application is called the common gateway interface (CGI). It is part of the Web’s Hypertext Transfer Protocol (HTTP)
If you are creating a Web site and want a CGI application to get control, you specify the name of the application in the “ Uniform Resource Locator” (URL) that you code in an HTML file. This URL can be specified as part of the FORMS tags if you are creating a form
For example, you might code:
<FORM METHOD=”POST” ACTION=”https://rshweb.com/cgi-bin/formprog.pl">
and the server at”rshweb.com” would pass control to the CGI application called “formprog.pl” to record the entered data and return a confirmation message. (The “.pl” indicates a program written in PERL but other languages could have been used.)
The common gateway interface provides a consistent way for data to be passed from the user’s request to the application program and back to the user. This means that the person who writes the application program can makes sure it gets used no matter which operating system the server uses (PC, Macintosh, UNIX, OS/390, or others). It’s simply a basic way for information to be passed from the Web server about your request to the application program and back again
Because the interface is consistent, a programmer can write a CGI application in a number of different languages. The most popular languages for CGI applications are: C, C++, Java, and PERL
An alternative to a CGI application is Microsoft’s Active Server Page (ASP), in which a script that is embedded in a Web page is executed at the server before the page is sent
Perl
Perl or Practical Extraction and Report Language is a family of script programming languages that are similar in syntax to the C language, including Perl 5 and Perl 6 . Perl is an open source, general-use, interpreted language. In general, Perl is easier to learn and faster to code in than the more structured C and C++ languages
Perl programs can, however, be quite sophisticated. It is often used for developing common gateway interface (CGI) programs because it has good text manipulation facilities, although it also handles binary files. Perl includes a number of popular UNIX facilities such as sed, awk, and tr. It can be compiled just before execution into either C code or cross-platform bytecode. When compiled, a Perl program is almost as fast as a fully pre-compiled C language program. A plug-in can be installed for some servers, such as Apache, so that Perl is loaded permanently in memory, thus reducing compile time and resulting in faster execution of CGI Perl scripts
CGI and Perl Resources
Perl Tutorial Hub
An authoritative list of recommended tutorials
Perl for Perl Newbies Series
Contains verbose slides filled with explanation, examples and anecdotes. Covers a basic subset of Perl
The Perldoc Tutorials
The tutorials that ship as part of the perl core. Start with perlintro and then continue with other tutorials
Perl.com
Beginners Introduction to Perl. A 6-part tutorial that covers the basics. this tutorial should get you started
Perl Maven
Perl and CGI script with Apache2
LPW: Beginners Perl by Dave Cross
Presentation slides by Dave Cross
Perl One-Liners Explained by Peteris Krumins
A series of posts about useful perl “one-liners” that may serve as a teach-by-example
Common Gateway Interface CGI documentation
Introduction, primer for getting started, interface spec, tutorial for writing ErrorDocument. Examples of behavior and programs
CGI Made Really Easy
Tutorial for writing CGI scripts to process Web forms. In English or German
CGI Programming 101
A course intended for anyone who knows HTML but doesn’t know Perl or CGI programming
Instantaneous Introduction to CGI Scripts and HTML Forms
Detailed explanation of CGI forms, how to use them and the mechanics behind how they work
Kali Linux Tutorial: What is it? How to Install it. How to Utilize it
CGI and Perl Scripts
ResourceIndex.com
Thousands of scripts and software for websites and web developers. PHP, Perl, CGI, MySQL, WebApps, SaaS
Matt’s Script Archive
Free Perl CGI Scripts
TheFreeCountry.com
Free Perl and CGI Scripts
The Perl Archive’s Guide
Listing nearly 4,000 cgi and perl programs
nms Project: Web Scripts Written by Experts
nms is a set of CGI scripts that are intended as drop-in replacements for the scripts at Matt’s Script Archive
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Originally published at https://rshweb.com.
