Sorry if I came off overly critical. Many people have had problems trying to use Mason with Apache::Session because of that article. This is why on the Mason website the link to that article describes it as outdated and steers people to newer documentation. (It probably should also steer them to the new handler...)
Eric Schwartz wrote:
Beggars can't be choosers, and all that, but would you mind telling me what handler you're talking about? I looked around for session handling and Mason, and that article was the best one I found in terms of explaining how it worked and how to use it.
Did you look on the Mason site, http://masonhq.com/? That's the best place to find information on Mason. A search for "session" on that site includes a reference to MasonX::Request::WithApacheSession, available from CPAN. This is mentioned in the administrator's manual that comes with Mason. It's possible that you have an old version of Mason that predates this.
Apache::Session::DBI (which is what the article refers to) is ancient and should not be used.
How can I know this? The documentation for Apache::Session::DBIStore (which A::S::DBI refers to) doesn't say anything about being obsolete or deprecated. Is there an archive of received wisdom somewhere I should be checking to validate articles like the one I found?
The latest Apache::Session on CPAN is version 1.54, released in October 2001. The last release that included a module called Apache::Session::DBI was version 1.03, released two years earlier. I'm not certain what CPAN.pm would do if you told it to install Apache::Session::DBI. It might install the old one, which would be very unfortunate. Is that how you installed it?
You shouldn't use the IPC locking in Apache::Session. You didn't mention which database you're using, but most of them have alternative ways of doing locking. In my opinion, the locking approach taken in Apache::Session is not a good one for the average web site and you should simply turn it off by using the NullLocker.
How?
By using Apache::Session::Flex. The configuration for MasonX::Request::WithApacheSession also lets you do this.
It's not particularly obvious from the documentation I can find that it's going to be used, or how to select alternative methods.
Look at the source and you'll see it. It's all much clearer in the more recent release though.
I installed Apache::Session from CPAN, and the docs refer to PosixFileLocker SysVSemaphoreLocker and NullLocker, but no perldocs for those modules are on my system.
The Apache::Session::PosixFileLocker and Apache::Session::SysVSemaphoreLocker modules are included with Apache::Session (although both are obsolete and only part of the old version that you installed). They have no documentation, so perldoc will not find them. The later equivalents (Apache::Session::Lock::File) do have docs.
'perldoc Apache::Session::DBI' says it uses A::S::PosixFileLocker, not A::S::SysVSemaphoreLocker. Are the docs wrong, or the code?
The docs are wrong. You can see it refers to the semaphore locker if you look at the source.
Basically, you stumbled across an old article that referred to an obsolete version of Apache::Session, and all of your problems stem from that. If you get a later version and check out the Mason handler and the newer documentation on masonhq.com, I think it will all start to make sense to you.
- Perrin
