Hi,

Im a WebDeveloper, recently i hve joined in a company where CGI is used to develop websites, but im new to it, i hve done in java & php but never known about CGi, can any one help me to know this and also tell me where can i get its tutorials, one more i need to know is when i searched for it in google, it says Perl CGI, C++ CGI, C CGI, CGI, is all of them same or different in writing code & its running environment, im confused about CGI please tell me its details, in my company coding is done in c++ and compiled to CGI, so please tell me where can i get this tutorial.

i need to know about,
file handling, cookies, running external command (like shellscript, doscommands) now, as i will be dealing with embedded system with this.

Please help me,


Thanks for your help in advance,

Common Gateway Interface is a standard for having external programs/scripts generate (dynamic) web pages. It basically works like this:

• A client (web browser) requests a page from a web server
• If the URL points to a CGI resource, the web server software passes the information to an external program or script using the CGI interface
• The program/script processes the request, and generates output that is sent back to the web server via CGI
• The output from the CGI program is passed directly to the client by the web server

CGI is an RFC standard (RFC 3875). The Wikipedia article on CGI isn't too bad and may be easier to understand than the RFC.

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Actually now im using CGI but my confusion starts when i see a CGI code in different manner ie i use C,C++ program to make a CGI ie i will write a code in C/C++ and compile it and i will get a CGI as an executable file but where as some codes are direct as html does they dont need any compiler at all why are they so...

Perl and Python are interpreted languages by design. C/C++ is a compiled language by design.
Software written in an interpreted language exists as a plain text script rather than a binary file. To run that software, you must have a suitable interpreter installed.
To the end user, there is usually no noticeable difference. (except that compiled languages may execute a little faster)

I'm sorry to have to ask this, but I'm too curious not to. How did you manage to get a CGI programming job (and presumably pass the technical interview) while knowing nothing about CGI?

good old TLA's
CGI
Computer Generated Images

it is a good thing that you included
"used to develop websites"

perl, python, ruby

As Ser Olmy said, try the Wikipedia article; its just the std on how interactive website code needs to work.

As a minor aside, Perl is actually compiled-on-the-fly http://www.perl.com/doc/FMTEYEWTK/comp-vs-interp.html, as opposed to eg bash which really is interpreted, thus leading to a large difference in speed.

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Very funny. Common Gateway Interface. Python and Ruby are never used for it.

i have passed interview for Web Developer using PHP & java(JSP & Servlets).

in my company we also have embedded systems, once when i saw a proj of it where they used CGI for web interface i just showed few mistakes in code so they handed over that web interface to me and asked few updates in that, without knowledge also i had to do it & i hve suceessfully done it but now i wanted to learn CGI completely so while learning i had these doubts.

Thanks to you all for clearing my doubts...

1. Perl is interpreted languages by design. C/C++ is a compiled language by design.
2. Common Gateway Interface. Python and Ruby are never used for it.

So now i conclude that CGI files can be made using Perl or C/C++.

Thanks once again to you all..

I always thought that CGI was Computer Generated Imagery like in Movies but I guess I am wrong.

Depends on context; there's only so many TLAs available ....

...and they can also be made with MANY other programs, INCLUDING Python and Ruby. If you have passed an interview to be a web developer and don't know these things, you are in for a very tough time at your new job.

Also, the word "doubt" and the word "question" mean different things.

If you're "using PHP to build web sites," guess what! You're right now using CGI to do that!

You see, what CGI basically is, is a way to specify that "a particular web-page" consists of a program that is to be executed, with the output of that program being what the user will eventually see. (I could offer a more complete explanation here, but this is the essential idea.)

So ... when you build a web-page "in PHP," that PHP is "a program that is to be executed." The user should never see the PHP source-code: what they see is the output that the PHP code, when executed, produces. And that is what "CGI" ... is.

Not necessarily. PHP can also be deployed as an Apache module. On Linux, it almost always is.

Python and Ruby are generally never deployed using CGI. Python is deployed using WSGI, and Ruby is usually deployed using the Passenger module (AFAIK for Ruby).

None of these technologies are "CGI". CGI is something very specific.

Granted, a stricter version of "CGI" would imply that the process that serves the web-page content is launched by the (Apache) web server each and every time. Which is one of the "issues" that I decided to try to gloss-over, because it really doesn't matter much in the end. Maybe the programming is built-in to Apache as a module; maybe it's running in a companion process (FastCGI); maybe it's launched every time. But these, to me, are mostly implementation distinctions; variations on "the essential idea," which is: that a program runs (somehow, somewhere), and what you get is its output.