PHP4, OOP, Frameworks and vars

Desdinova

Unfortunately I am limited to PHP4 on my server, and since I've started using OOP not too long ago, I run into some frameworking issues.

Example:
I have a class User, which generates a userID for me. I instantiate User from my index.php, in var $user.

I also have a class Core, which handles all my actions (ie. building a menu, building content, etc), but does so by instantiating other classes. So Core::BuildMenu() may actually instantiate a class Menu, which then gets the menus I want the user to see.

However, class Menu needs to know my userID, so it can load the appropriate menus. From my Menu class I cannot reach the var $user, so I cannot obtain $user->userID. 🙁

I could of course pass the userID var to my Core class, and from there to my Menu class, but this seems like bad practice to me.

I could also store the userID in the Session, but I can't imagine that to be safe.

Does anyone know how I should or could handle this?

laserlight

I could of course pass the userID var to my Core class, and from there to my Menu class, but this seems like bad practice to me.

If Core needs constant access to something from User, then perhaps it is correct to store a reference to User in Core, but since this is PHP 4, the reference must literally be a reference, otherwise you would end up with two User objects.

I could also store the userID in the Session, but I can't imagine that to be safe.

It is safe since your session is stored server side.

Desdinova

Is it good practice to use Session vars as a superglobal to store information which can be shared among multiple classes without having to reinstantiate the classes?

laserlight

Is it good practice to use Session vars as a superglobal to store information which can be shared among multiple classes without having to reinstantiate the classes?

It depends. That may be a job for a singleton, but a singleton is technically infeasible in PHP 4. However, in this case the variable is intended to persist across page views (unless you have dynamically changing user ids, which is unusual), so the use of a session is appropriate.

Desdinova

Alright thanks, I'll go for session storage for the ID.

I'm kind of scared of using it though, I remember having used session storage a year ago, and getting a weird warning: 'Warning: Unknown: Your script possibly relies on a session side-effect which existed until'.

Do you know what triggers this warning and how to prevent it?

laserlight

What is the exact warning?

Desdinova

this is:

Warning: Unknown: Your script possibly relies on a session side-effect which existed until PHP 4.2.3.

I googled around a bit and found a theory. It has something to do with register_globals being off, and using varnames that match global values (ie. $uno matches $_SESSION['uno']). The theory says you cannot have these matches anywhere in your script, or PHP will think you're trying to use a global, which is set to off.

This should trigger the warning:

$varname = $_SESSION['varname'];

untested.
The warning can be disabled through htaccess or php.ini, but that's not really a solution I'd say.

NogDog

See the info on this page about the "bug_compat" settings. From what I've seen, it generally raises its ugly head if you try to access an unset $_SESSION element or set one to null. If you do not depend on the "undocumented feature/bug that allows you to initialize a session variable in the global scope, albeit register_globals is disabled," then you could turn off the session.bug_compat_42 setting.