Beginning Web Development With Perl : From Novice to ... - Nabo

CHAPTER 1 ■ THE CGI MODULE 21Setting Multiple CookiesYou may find that one cookie isn’t sufficient for your application. In that case, you have twoprimary solutions:• You could simply set multiple cookies, each corresponding to a different setting or preference.This method works well for a few cookies, but remember that there’s a limit of20 cookies per domain.• If the application has a large number of cookies, a better solution is to create a sessionID, store that session ID in a database, and tie that database into the settings and preferencesthat need to be stored for the application.Storing a session ID in a database has the advantage of giving your application virtuallyunlimited settings that it can store in the background, since only one cookie is sent to thebrowser. Also, since only one cookie is sent to the browser, you will save bandwidth, thusmaking the site seem quicker to the user. Granted, this is less important for LAN-basedapplications, but any savings of bandwidth are good savings. This section shows how to setand read multiple cookies using the CGI module.You can send multiple cookies to the browser by first creating the cookies, as you’ve done,and then passing the cookies as an array reference to the cookie() function. Listing 1-10shows an example.Listing 1-10. Sending Multiple Cookies Using CGI.pm#!/usr/bin/perl -Tuse strict;use CGI qw/:standard/;my $cookie1 = cookie(-name=>'testcookie',value=>'testcookievalue',expires=>'+7d');my $cookie2 = cookie(-name=>'secondcookie',value=>'secondcookievalue',➥expires=>'+1d');print header (-cookie=>[$cookie1,$cookie2]),start_html('CGI Cookie Test'),p("You've received a cookie\n"),end_html;exit;This code has only two differences from the code in Listing 1-9:my $cookie2 = cookie(-name=>'secondcookie',value=>'secondcookievalue',➥expires=>'+1d');print header (-cookie=>[$cookie1,$cookie2]),The first line creates a scalar containing a cookie with a name of secondcookie, a value ofsecondcookievalue, and an expiration of one day into the future. Notice that the expirationof $cookie2 is different from that of the other cookie in this example.