Perl - Apache::Session - Error Handling

Question

I'm using Perl CGI and Apache::Session in my web application.

When setting up an Apache::Session using tie like this:

tie %session, 'Apache::Session::MySQL', $id, {
    DataSource => 'dbi:mysql:apache_session', 
    UserName   => 'root',         
    Password   => '',           
    LockDataSource => 'dbi:mysql:apache_session',
    LockUserName   => 'root',
    LockPassword   => ''
};

How do I catch the error that occurs when $id is not a valid session in the database? I need to create a new session ID instead of having the application die with a 500 http error.

This situation occurs when the user has an outdated cookie with a session ID that has been removed from the database.

Answer 1

If the $id variable has a value of undef, Apache::Session creates a new session ID. Now if $id is defined but does not appoint a valid session here then an exception will be thrown.

One way you could do this is to wrap tie in an eval block.

eval {
     tie %session, 'Apache::Session::MySQL', $id, {
         DataSource => 'dbi:mysql:apache_session', 
         UserName   => 'root',         
         Password   => '',           
         LockDataSource => 'dbi:mysql:apache_session',
         LockUserName   => 'root',
         LockPassword   => ''
     };
};

If an exception is thrown, you can check to see whether the message indicates that the session isn't valid.

if ( $@ ) { ... }