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Perl Script Writing

  1. Introduction

    Language

  2. Variables
  3. Operators
  4. Character Meanings
  5. Control and Loops
  6. Functions
  7. Array Functions
  8. String Functions
  9. Math Functions
  10. Reading and Writing
  11. Using Cookies

    Examples

  12. Printing a file
  13. Hit Counter
  14. Poll Receiving

    Appendices

  15. Terms
  16. Credits

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Perl Cookies

Cookies are used to maintain state information between the web server and the client browser. For example, if the client filled out a survey, rather than displaying the survey form the next time they view, the results of the survey may be displayed:

Setting a cookie

The below sets a cookie to expire in 1 year. It sets a cookie name of "ospoll" and a value of "done" to indicate an operating system poll was taken by the client. 

#!/usr/local/bin/perl
# Place a cookie on the user's machine to show the poll was taken.
$fut_time=gmtime(time()+365*24*3600)." GMT";  # Add 12 months (365 days)
$cookie = "ospoll=done; path=/; expires=$fut_time; $secure";
print "Set-Cookie: " . $cookie . "\n";

Using CGI.pm 

#!/usr/local/bin/perl

use CGI;
$cgiCkie = new CGI;
$fut_time=gmtime(time()+365*24*3600)." GMT";  # Add 12 months (365 days)

$cookie = $cgiCkie->cookie(-name=>‘ospoll’,
               -value=>‘done’,
               -expires=>$fut_time,
               -path=>‘/’);
print $cgiCkie->header(-cookie=>$cookie);

Getting a Cookie

The following example reads the cookies into the string value $recvd_cookies. Then it splits each cookie into an array of strings with the line:

@cookies = split /;/, $rcvd_cookies;

Then it checks each cookie in the array to see if a cookie name of "ospoll" with the value of "done" or "start" exists and sets appropriate flags.



GlobalSpec - The Engineering Search Engine
#!/usr/local/bin/perl

#Check to see if a cookie with the name ospoll1 and value done or start are on the client
$rcvd_cookies = $ENV{'HTTP_COOKIE'};
@cookies = split /;/, $rcvd_cookies;
foreach $cookie (@cookies)
{
   if ($cookie eq "ospoll1=done")
   { 
      $polltaken=1; #Poll was previously taken
   }
   if ($cookie eq "ospoll1=start")
   {
       $pollready=1;
   }
}