Best practices question involving classes.

[Stinger51]

[FONT="Verdana"]
It's been a pleasure working with classes again and PHP5 after wandering around in PHP4 and using its idea of a "class." The last time I was involved with using real classes was with VB6 and C++. So, my PHP4 coding was a bit of a kludge at times.

Now then, I use a lot of session vars, as most do here. And I am writing a new class that needs some of this session data. My question is, should I convert this session data to regular vars and then pass this data to the class (via its constructor)? Or should I just allow the class to use the session vars directly?

I don't feel comfortable with the latter idea. It just seems to "global" to me. And we all know how global vars can get you into trouble.

So, even tho it's extra work, I've opted for the first method. I also tend to use this method, e.g. convert the session vars to local vars when working with any form data. It's just easier for me to work with the variable:

$my_local_var = $_SESSION['svSomeData']

than it is to work directly with: $_SESSION['svSomeData']

Comments are appreciated.

[/FONT]

[sneakyimp]

I would agree that it's probably wise to pass in the session data into your class either in the constructor or by explicitly setting class vars:

$myObj = new myClass();
$myObj->someVar = $_SESSION['someVar'];

I would imagine it would be enough to just have one class variable to hold all the session data but that might ultimately get you into trouble if your code project has to merge with another code project. You might have some naming collisions or something.

[NogDog]

Personally, I don't think using $SESSION bothers me all that much since it's a built-in super-global for PHP and thus is always available and a well understood aspect of PHP. (I.e.: any time you see $SESSION if a piece of code, you know where it's coming from.)

One issue I would have with passing the $SESSION data into an object is: what happens if another object alters the session data? If the first class needs to know about this, then you'll need to pass the $SESSION array by reference to each. Also, will you need to add a mechanism to write the data back to $SESSION? If so, how do you make sure multiple objects using $SESSION data don't overwrite each other's data in the wrong sequence?

One possible compromise might be to use some sort of singleton class that loads the session data in its constructor, and has a __sleep() method that saves its session data back to the $_SESSION array. Then you could either pass that object or instantiate it within each class that needs it.