MVC - functionality in the controller/model

Question

I'm trying to improve some PHP scripts using a OO design (it's procedural now with some OO parts). Just to be clear, I'm not trying to build a full MVC application, but I am trying to seperate parts as much as possible. I've never used MVC before in PHP (only a little bit in Java).

When using Google, I find 100 different MVC approaches for PHP and I can't find a good book on this subject. If anyone could suggest me a good book on OO design in PHP, it would be much appreciated.

Currently, a part to add a user to the database (assuming a user only contains a firstname for now), looks like this (users.php):

$validator = new UserValidator();

if ($validator->validate($_POST['user_firstname']))
  $result = $db->execute("INSERT INTO `users` (`user_firstname`) VALUES (?)", $_POST['user_firstname']);

Knowing that adding users may be done at multiple places and I don't want code repeat, I will create a usermodel. This class will contain a method addUser(). The thing I'm a bit stuck with is the validation. The UserValidator will check if all fields are filled in correctly.

I could do this:

$validator = new UserValidator();

if ($validator->validate($_POST['user_firstname']))
  $result = $user->addUser($_POST['user_firstname']);

But I could also do this:

$result = $user->adduser($_POST['user_firstname'];

Now the User-class will contain the validator and the addUser()-method will perform this validation. Assuming the above code is the controller, what option is the best? Delegating the validation functionality to the model or doing it in the controller?

The same problem applies when getting information of a certain user. Not everyone may get this info, so my code could look like this:

if ($user->hasAccess($_SESSION['id'], $_GET['id'])
  $user->getUserById($_GET'id']);

(The hasAccess()-method will check if the user who is logged in can view details of a certain user id)

But I could also just call getUserById() and check if you have access in that method. Which option is the best?

Thank you!

Fred Wilson · Accepted Answer · 2011-04-10 15:06:05Z

1

In your first example, putting the validation logic in the call $result = $user->adduser($_POST['user_firstname']; is the cleaner way to go. Keep your controllers thin and let your models handle as much of the logic as possible. Ideally, your controller is coordinating data that will be passed to your "view", whatever that may be.

Your second example is less clear. You might have logic in hasAccess() that doesn't belong in getUserById() or you might be creating more work for getUserById() than makes sense for the method. It's always best to keep similar functionality as close as possible, but there are some assumptions that can't be made just by looking at the two lines you posted.

answered Apr 10, 2011 at 15:06

Fred Wilson

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4 Comments

Bv202 Over a year ago

Thank you for the answer. I've improved the second example a bit.

Fred Wilson Over a year ago

If hasAccess() is only used in the context of calling getUserById(), then there's probably no reason to keep it separate. Otherwise, keep your logical units as discrete as possible, especially within classes.

Bv202 Over a year ago

It's not. When editing a user, deleting a user, etc. there also needs to be done a check to see if you have access to that specific user.

Fred Wilson Over a year ago

Calling hasAccess() in getUserById() is the cleaner way to handle the controller, IMO. Too many if statements in a controller make me think about refactoring.

Scott Harwell · Accepted Answer · 2011-04-10 14:15:54Z

0

I user CakePHP pretty frequently, an MCV framework for PHP, and in such a case, the UserValidator would be broken out into a separate entity called a "component." The controller would call the component to do the validation before the save and then, if all passes, the data would be sent to the model for a save.

I think creating a separate validator class that can check your data in the controller may be the way to go.

answered Apr 10, 2011 at 14:15

Scott Harwell

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