HABTM form validation in CakePHP

Question

I have a Projects table and a Users table which are linked by a HABTM relation. In the \"add\" new Project page I have a multiple checkbox section to select Users for the ne

Answer 1

I stumbled on the same issue, but now - 3 years later - with CakePHP 2.3.

To be clear; Group has and belongs to User. I've had a form like this:

// View/Groups/add.ctp
echo $this->Form->input('name');
echo $this->Form->input('User');

With the validation rule like in user448164's answer:

// Model/Group.php
public $validate = array(
    'User' => array(
        'rule' => array('multiple', array('min' => 1)),
        'message' => 'Please select one or more users'
    )
);

That didn't work, after Googling for it, I found this question which couldn't still be the best solution. Then I tried several things, and discovered this to work just fine:

// View/Groups/add.ctp
echo $this->Form->input('name');
echo $this->Form->input('Group.User');

Way too easy solution, but had to dig into it to find out it works this way.

Hopefully it helps somebody one day.

Update for CakePHP 2.4.x (possibly 2.3.x as well)

When I wrote this answer, I was using CakePHP 2.3.x. Back then it worked perfectly for both validating and saving the data. Now when applying the same code on a new project, using CakePHP 2.4.x, it didn't work anymore.

I created a test case, using the following code:

$data = array(
    'User' => array(
        'Client' => array(8)
    ),
);
$this->User->create();
$this->User->saveAll($data);

My first thought was: Saving all means saving all "root" models, what actually makes sense to me. To save deeper than just the "root" ones, you'll have to add the deep option. So I ended up with the following code:

$data = array(
    'User' => array(
        'Client' => array(8)
    ),
);
$this->User->create();
$this->User->saveAll($data, array('deep' => true));

Works like a charm! Happy coding. :)

Update (2014/03/06)

Struggling with the same problem again, in this case with hasMany instead of habtm. Seems like it behaves the same way. But I found myself looking for this answer again, and got confused.

I'd like to make clear that it's key to use Group.User instead of User in your input. Else it won't use the User model validation.