Apache::Session provides persistence to a data
structure. The data structure has an ID number, and you can retrieve
it by using the ID number. In the case of Apache, you would store the
ID number in a cookie or the URL to associate it with one browser,
but how you handle the ID is completely up to you. The flow of things
is generally:
Tie a session to Apache::Session.
Get the ID number.
Store the ID number in a cookie.
End of Request 1.
(time passes)
Get the cookie.
Restore your hash using the ID number in the cookie.
Use whatever data you put in the hash.
End of Request 2.
Example B-1. session.pl
# pull in the required packages
use Apache::Session::MySQL;
use Apache;
use strict;
# read in the cookie if this is an old session
my $r = Apache->request;
my $cookie = $r->header_in('Cookie');
$cookie =~ s/SESSION_ID=(\w+)/$1/;
# create a session object based on the cookie we got from the
# browser, or a new session if we got no cookie
my %session;
eval {
tie %session, 'Apache::Session::MySQL', $cookie,
{DataSource => 'dbi:mysql:sessions',
UserName => $db_user,
Password => $db_pass,
LockDataSource => 'dbi:mysql:sessions',
LockUserName => $db_user,
LockPassword => $db_pass,
};
};
if ($@) {
# could be a database problem
die "Couldn't tie session: $@";
}
# might be a new session, so let's give them their cookie back
my $session_cookie = "SESSION_ID=$session{_session_id};";
$r->header_out("Set-Cookie" => $session_cookie);
After %session is tied, you can put anything but
file handles and code references into
$session{_session_id};, and it will still be there
when the user invokes the next page.
It is possible to write an Apache authentication handler using
Apache::Session. You can put your authentication
token into the session. When a user invokes a page, you open his
session, check to see if he has a valid token, and authenticate or
forbid based on that.
An alternative to Apache::Session is
Apache::ASP, which has session-tracking abilities.
HTML::Embperl hooks into
Apache::Session for you.
Available from CPAN. See the module manpage for more information.
