#!/usr/bin/perl

#

# Redirection CGI

# Ken Wronkiewicz (wh3947a@tso.cin.ix.net)

#

# Version 1.00 - Inital release - Ken Wronkiewicz(wh3947a@tso.cin.ix.net)

# Version 1.01 - Bug fix version - I forgot a space - Ken Wronkiewicz

#		 (wh3947a@tso.cin.ix.net)

# Version 1.10 - Cleaned up release - Uses associative arrays

# 		 and cleaner structure.  Added docs - 

#		 Ken Wronkiewicz(wh3947a@tso.cin.ix.net)

#

# How this works -

#  First, we check for Microsoft Internet Explorer, because it sends a

#  Netscape HTTP_USER_AGENT.  Then, we screen out pre - 2.0 Netscape

#  Navagators.  If the browser is none of the top two, it must be 

#  2.0 or 3.0.  We also check for LYNX in order to send the user to the 

#  text only page.  If the user isn't one of these, we send them to

#  the average browser page.

#

# To adapt to your page - 

# 1) Place this file, renamed index.cgi, into the directory you with to

#    make independant

# 2) Create four directories, avg/ ie/ ns/ and text/

# 3) Remove your index.html and create four tailored index.html files

#    for each of the four directories.

# 4) Specify all pathnames without an index.html.  For example, if your

#    netscape specific file is at "http://www.yyy.com/ns/index.html",

#    you should specify the URL as "http://www.yyy.com/"

#

# To adapt to a different structure -

#  The %Locations associative array holds the location the user is sent 

#  to.  So, if the page you want Netscape users to go to is at

#  "http://www.yyy.com/foo/index.html" and this is at 

#  "http://www.yyy.com/", you want to set the value after 'NS' to 

#  "/foo/index.html".

#

# If this program doesn't work -

#  Your server might be set up improperly.  Normally, the server will

#  try to find a file named "index.html" and then a file named "index.cgi"

#  before it sends an FTP style directory.  So, if you get a FTP style

#  directory instead of the page, your server is set up like this.

#  

#  Also, make sure that your server is set up to treat files with a .cgi

#  extension as CGI applications.

#

# To support a new browser -

#  You need to come up with a key name for it.  Just use the first few 

#  letters of the browser name or something.  Then, you want to make a 

#  new directory for the new browser.  Find out what HTTP_USER_AGENT 

#  string the browser sends out and then add a test.

#

# To find out what HTTP_USER_AGENT your browser is sending

#  If the URL you use is "http://www.yyy.com/", you want to

#  go to "http://www.yyy.com/index.cgi?id".  The HTTP_USER_AGENT your

#  browser sends will be the result of the script.

#

# For further help -

#  E-mail me at wh3947a@tso.cin.ix.net

#

# License -

#  This software has been written by me.  If you use it, I want to know.

#  So tell me if you use it.  You can modify it, as long as I know

#  about it and you give me credit.

#  It is freely distributable.  





# Read the content data - Does nothing, really.  Just in case

# somebody tries to POST something to the CGI.



read(STDIN, $buffer, $ENV{'CONTENT_LENGTH'});



# Set up the associative array with the list of different locations

# that your page could possibly be.  The key associated with

# the location comes first.  The actual location comes second.



%Locations = (

'MSIE', 'http://www.volkszone.com/VZi/index.php', #Path for the Internet Explorer page

'NS', 'http://www.volkszone.com/VZi/index.php', #Path for the Netscape page

'TEXT', 'http://www.volkszone.com/VZi/index.php', #Path for the text-only page

'AVG', 'http://www.volkszone.com/VZi/index.php', #Path for the average page

# Add additional locations here - first the key and then the location.

);



# Get the HTTP_USER_AGENT variable - This is the identification string

# that your browser sends out when it asks for a page.



$Agent = $ENV{'HTTP_USER_AGENT'};



# Decide which page to send the user to - This uses regular expression

# tests to decide if a particular string is in the HTTP_USER_AGENT

# variable and then sends the proper redirect.



CHECK: {

 if ($ENV{'QUERY_STRING'} eq "id") {&ID; last CHECK; }

 if ($Agent =~ /MSIE/i) {&Redirect($Locations{'MSIE'}); last CHECK; }

# Add more Internet Explorers here

 if ($Agent =~ /^Mozilla\/1.*/i) {&Redirect($Locations{'AVG'}); last CHECK; }

# Add more Netscape versions here

 if ($Agent =~ /^Mozilla\/*/i) {&Redirect($Locations{'NS'}); last CHECK; }

 if ($Agent =~ /^Lynx/i) {&Redirect($Locations{'TEXT'}); last CHECK; }

# Add new browsers here

 &Redirect($Locations{'AVG'});

}



# Redirect subroutine.  Given a location to redirect to, it will give you the new 

# document.  



sub Redirect {

 local($location) = @_;

 print "Location: $location\n\n";

# Just in case the user's browser does not support redirections properly, we'll

# send out a document to tell them to go to the new location.  I have yet to

# see a browser that doesn't, but I figure it's better to be safe.

 print "<HTML><HEAD><TITLE>OOOOPS</TITLE>\n";

 print "<BODY><P>It seems we cannot seem to redirect you, please go to <A HREF=\"$Locations{'TEXT'}\"></P>";

 print "</BODY></HTML>";

}



# Testing subroutine.  Prints out the type of browser you are using.



sub ID {

  print "Content-type: text/plain\n\n";

  print "$Agent";

}



# End of redirecton.