Free Scripts
What are CGI Scripts?
The
difference between your web site just being a virtual billboard and
it being an interactive web site, is having the ability to get
information to and from your viewers. The Web provides a mechanism
for accomplishing this, CGI, the Common Gateway Interface, using CGI
scripts. An example of a CGI script would be: Shopping cart systems,
hit counters, guestbooks, order forms, mail, maps, etc.
CGI scripts are the way most servers communicate
with other programs and scripts. CGI scripts are simple text files,
lines of code, that are interpreted as requested by the server. A
CGI script will work together with other programs and with the HTML
content of your web page. Since HTML alone only allows for
information to be displayed, CGI scripts give HTML the ability to
interact with the visitor. CGI scripts can be written in Perl, PHP,
C, Visual Basic, or Python. CGI is not a programming language
itself. It's more of a protocol for communication between the web
server and the script. Perl and PHP seem to be the languages of
choice, because they are easy to learn and are very
portable.
How Does A CGI Script
Work?
A CGI Script is a collection of lines of code that
contain instructions for the server. Unlike a simple HTML document
request, a CGI-BIN (Common Gateway Interface) request requires
something a whole lot smarter than a regular HTML request for
content from the server. When you click on a link that looks like:
http://100best-web-hosting.com/cgi-bin/Guestbook/guestbook.cgi, you
are really instructing the server to run an actual program that
handles only this one type of request. In this case it runs the
program that calls up the form that allows you to make an entry in
the guestbook. Here is a breakdown of what actually happens:
-
Your browser sends the request shown above to the
server.
-
The server runs the guestbook.cgi program.
-
The guestbook.cgi program realizes that you are not adding
anything yet, so it makes the decision to create and return to
you, a blank data entry form.
-
Your browser then displays this form as it would any other
HTML document.
-
So you take a moment and fill in all the fields and click
on the SUBMIT button. Now a more complex series of actions take
place. The command in the browser location window may look
something like
this:
/cgi-bin/Guestbook/guestbook.cgi?name=joe&email=joe@mail.com
-
When the CGI receives the request, it executes a program
called guestbook.cgi that is located in the Guestbook directory
under cgi-bin. What is different now is that in addition to a
program request, information is being fed to the CGI script.
This is what the script then does:
-
Load the guestbook.cgi program into memory for
running.
-
It notices that it has to split up
the information using the & as a way of telling where one bit
starts and ends.
-
Seeing that the e-mail has a name
in it, sends a thank you note to the person that signed the book.
-
Sends a note to the webmaster that a new entry is in the
guestbook.
-
Takes all the input data, and uses the information to
create a new entry that is tagged onto the guestbook.html
document.
-
Creates an HTML document saying "Thank you for signing my
guestbook!" that is returned to the browser. And the CGI's job is
finished.
The important concept is that in order to use CGI-BIN or a
CGI script, you must create a real, however big or small computer
program. It is not embedded in your HTML document, but it is
installed in your cgi-bin directory located on your
server.
What are Free CGI
Scripts?
Free CGI scripts are prewritten applications in
PERL or other programming code, that you can download or copy
straight from the provider. By utilizing the many free CGI scripts
available you can have CGI features on your site (guestbook, forms,
etc.), but don't need any programming skills to create these
features on your own. Usually the free CGI scripts will run from the
CGI providers servers, so you don't have to deal with complex
installation and maintenance procedures. Free CGI scripts like hit
counters and guestbooks are offered by most web hosts. If your web
host doesn't offer these features, here are a few resources for Free
CGI Scripts:
Hot Scripts
www.hotscripts.com
Script
Search
www.scriptsearch.com
CGI Resources
cgi-resources.com,
Free-Scripts.net ,
free-scripts.net
Do I need CGI Scripts in the hosting
package I choose?
In order
to use CGI programs, your server must be configured to support them.
Check with your system administrator as to whether or not you can
use them, and if so, where your CGI programs must reside. If you are
not allowed to do CGI on your server- consider moving to someplace
where you can, or finding somebody to host your scripts. If you
would like to have a shopping cart, guestbooks, counters, or other
visitor interactive type features on your site you will need a web
host that supports CGI scripts.