Storing objects in PHP session

Question

The PHP documentation says \"You can\'t use references in session variables as there is no feasible way to restore a reference to another variable.\"

Does this mean

Answer 1

That's the expected behavior. Storing a reference to an object would only work if the memory location for the object didn't change. In a stateless protocol like HTTP, application state is not persisted between requests. The next request may be handled on another thread, process, or another server.

Given the inherent stateless nature of a web application, holding a pointer to a memory location is useless. Therefore the object's state must be broken down into a storage format, saved or transmitted, and then reconstituted when needed. This process is known as Serialization.

You can choose to serialize the entire object into session (which maybe dangerous depending on the depth of your object graph, since your object may hold references to other objects and those would need to be serialized as well), or if the object can be reconstituted by querying the database on the next request you may just stash an ID in the session.

[EDIT]

JPot pointed out that objects are automatically serialized to $_SESSION, so explicit serialization isn't necessary. I'll leave the answer for posterity, but obviously it doesn't help your problem.