How to Install a CGI Script and Increase Web Site Interactivity	3.0/5.0 (5 votes total) Rate: Select 1 - Terrible 2 - Poor 3 - Average 4 - Good 5 - Outstanding
Herman Drost December 22, 2004

You may have delayed cgi script installation due the apparently complex process. Well, I avoided it also for several years, however if you want to increase your web site's interactivity it's a necessity to know how to do it. It's not hard to learn and you don't have to be a programmer.

What is CGI ?

Common Gateway Interface or CGI is a program that can interact with an html form on your web site, and processes the results on your server using a cgi script. The result generated is a dynamic web page. The cgi script is written in a language called PERL ("practical extraction and reporting language").

Uses of CGI scripts

CGI scripts are most commonly used for creating user interaction with an html form on your web site. Other uses include: autoresponders, shopping carts, counters, mailing list managers, ad management, surveys, polls, discussion boards, content management, calendars and click tracking.

There are 100s of free cgi scripts that can be found on the Net. Just do a search on Google for "free cgi scripts" or visit the resources at the end of this article.

We will create an html email form to collect the name, email address and comments of subscribers using a secure cgi formmail script. The form results will automatically be sent to your email address.

Steps to installing your own cgi script

1. Check that your web host supports CGI - your web host will have a cgi-bin folder installed on the server. The cgi-bin is a special directory in the server where all the files which require security are kept. This is where you will upload your cgi script once it has been modified.

2. Download the cgi script - this is a secure cgi formmail script. Spammers can't access and harvest your email address from this script.

http://nms-cgi.sourceforge.net/formmail.zip

3. Read the documentation that comes with the script - this will give you a thorough understanding what changes you need to make to have it work correctly with your web site and server. It will also provide you with some examples.

Editing your script

4. Open and edit your cgi script using notepad (don't use an html editor as this can create errors).

5. Remove the html tags from the script (at the top and bottom).

6. Change the path to perl to: #!/usr/bin/perl -wT (this is the first line of the script to be edited).

7. The section of the cgi script shown below, are the other minimum fields to fill out in the script (replace the fields in the script you downloaded with the changed fields in the script below).

# USER CONFIGURATION SECTION
# --------------------------
# Modify these to your own settings. You might have to
# contact your system administrator if you do not run
# your own web server. If the purpose of these
# parameters seems unclear, please see the README file.
#
BEGIN
{
$DEBUGGING = 1;
$emulate_matts_code= 0;
$secure = 1;
$allow_empty_ref = 1;
$max_recipients = 1;
$mailprog = '/usr/lib/sendmail -oi -t';
$postmaster = '[email protected]';
@referers = qw(yourdomain.com);
@allow_mail_to = qw();
@recipients = ();
%recipient_alias = ('siteowner' => '[email protected]',);
@valid_ENV = qw(REMOTE_HOST REMOTE_ADDR REMOTE_USER HTTP_USER_AGENT);
$locale = '';
$charset = 'iso-8859-1';
$date_fmt = '%A, %B %d, %Y at %H:%M:%S';
$style = '';
$no_content = 0;
$double_spacing = 1;
$wrap_text = 0;
$wrap_style = 1;
$send_confirmation_mail = 0;
$confirmation_text = <<'END_OF_CONFIRMATION';
From: [email protected]
Subject: Subject of Your Contact Form

(short note here->> )Thank you for your interest. We will respond shortly.

END_OF_CONFIRMATION
#
# USER CONFIGURATION << END >>
# ----------------------------
# (no user serviceable parts beyond here)
--------------------------------------------------------------------------------

$postmaster = Who's sending the email
@referrers = Domains that are allowed to host the script
%recipient_alias = Whom the script will send email to

In my form:

[form action="http://www.mydomain.com/cgi-bin/formmail.pl"
method="POST"]
[input type="hidden" name="recipient" value="siteowner"]

You can see how the siteowner variables match up in the .pl script and in my form. This way, nobody can tell what address the form is being emailed to!

8. Rename your cgi script - name your script something else besides formmail (ie contactus.pl), as this is the most common name people use. This will prevent spammers from harvesting your email address.

9. Create your html form (contactus.htm)
Note: Replace [ ] with < > for your form to work.

[html]
[head]
[title]Contact Us[/title]
[/head]
[body bgcolor="#FFFFFF" text="#000000"]
[form method="post" action="http://www.yourdomain.com/
cgi-bin/contactus.pl"]
[input type=hidden name="recipient" value="siteowner"]
[input type=hidden name="subject" value="Subscribe Me Please"]
[input type=hidden name="required" value="fullname,email"]
[input type=hidden name="redirect" value="http://www.yourdomainname.com/thankyou.htm"]
Full Name[br]
[input type=text name="fullname"]
[br]
Email Address[br]
[input type=text name="email"][br]
[br]
Comments[br]
[textarea name="comments"][/textarea]
[br]
[br]
[input type="submit" name="Submit" value="Submit"]
[/form]
[/body]
[/html]

10. Create a confirmation page (ie thankyou.htm) - this will automatically thank people for filling in your form. It can be a simple html page with the comments "Thank you for your interest. We will respond shortly".

Uploading the cgi script and html email form.

Use your favorite FTP program for uploading to your server (I use
SmartFTP.com which you can download for free).

11. Set permissions to 755 - in SmartFTP right click on the script file you wish to upload, click on Properties/CHMOD and set the permissions to 755.

12. Upload the cgi script - there are two modes of uploading, ASCII and Binary. Upload the cgi script (contactus.pl) and any txt files in ASCII mode. Upload the script to the cgi-bin folder. If you don't follow this you will not be able to execute the script.

13. Upload the html form and any image files like .jpg or .gif in Binary mode.

14. Test your cgi script by filling out the html email form and submitting it. You should receive an immediate confirmation.

By adding interactivity to your web site using a cgi script, you can expand the functions of your web site and create a more interesting experience for your visitors. This will keep them coming back and help you stay ahead of your competitors.

Resources

Formmail script
http://nms-cgi.sourceforge.net/formmail.zip

Free CGI scripts
Scriptarchive.com
Hotscripts.com
cgi-resources.com