Question

Adding a Channel File greatly improves the performance of the Facebook JS SDK by addressing issues with cross-domain communication in certain browsers as per the documentation.

The contents of the channel.html file should be just a single line:

<script src="//connect.facebook.net/en_US/all.js"></script>

The channel file should be set to be cached for as long as possible.

In PHP:-

<?php
 $cache_expire = 60*60*24*365;
 header("Pragma: public");
 header("Cache-Control: max-age=".$cache_expire);
 header('Expires: ' . gmdate('D, d M Y H:i:s', time()+$cache_expire) . ' GMT');
 ?>
 <script src="//connect.facebook.net/en_US/all.js"></script>

How to create the similar file in Perl?

Answer 1

First, set up your channel.html file as a cgi-script (assuming that server runs under Apache) – you need to edit configuration file to add something like this:

<Files "channel.html">
AddHandler cgi-script .html
Options ExecCGI
</Files>

and then just rewrite this file in Perl:

#!usr/bin/perl

binmode STDOUT;
my $cache_expire = 60*60*24*365;
print "Pragma: public\n";
print "Cache-Control: max-age=",$cache_expire,"\n";
print 'Expires: ', Mailtime(time+$cache_expire),"\n";
print 'Content-Type: text/html; charset=utf-8'."\n\n";
print '<script src="//connect.facebook.net/en_US/all.js"></script>';

sub Mailtime { 
my @months = qw(Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec); 
my @wdays = qw(Sun Mon Tue Wed Thu Fri Sat); 
my ($sec,$min,$hour,$mday,$mon,$year,$wday) = gmtime($_[0]); 
return sprintf("%s, %02d %s %d %02d:%02d:%02d GMT", $wdays[$wday], $mday, $months[$mon], $year+1900, $hour, $min, $sec); 
}