No you are right, the original approach lacked some elegance… and had some flaws. Too bad I didn’t have much time to come back to it and test out some other things.

There’s one thing I don’t like in the original approach:

We are about to save a new Post… let’s add a validation rule to our Tag model

So, we want the *Post* to have at least one tag. We should be validating the Post model. Maybe there are 3 others models with a HABTM relationship with Tag, and their validation rules are different.

Of course I don’t have a better idea; I’m just critizicing :-).

What I’ve been using are manual validations in the controller or using the beforevalidate() method, but those have already been pointed out.

Secondary model knowing about primary model, is very much cake-like… the fact that it doesn’t validate the whole form is definitely a problem. Well, it sparked some good conversation and solutions so it was worthwhile to write about it, I guess :)

And… thank you for sharing your solution as well.

Further to my previous comment, I think the best method for validating the data is simply to do this:

if(empty($this->data['Tag']['Tag'])) {
$this->Post->Tag->invalidate(‘Tag’,'min_tags’);
}

Then proceed with a

$this->Post->save($this->data);

to validate the rest of the form.

It’s simpler, requires no hacks and is much shorter…

This works, but it’s true that it doesn’t validate the whole form at once.

It’s also…un-cakelike ;-) meaning the secondary model has to ‘know’ about the primary model. Which kind of defeats the point, no?

There MUST be a better way. I tried fooling with multiple, but didn’t get ANYWHERE.

PS your blog seems to pop up whenever I have a cake issue and do a search…

Excellent, thanks for sharing.

This line:
$validates = $validates && $this->Post->validates();

Should be:
$validates = $this->Post->validates() && $validates;

Otherwise the $this->Post->validates() function won’t run, because PHP short-circuits the operation.

function add() {

if(!empty($this->data)) {

$this->Post->Tag->set($this->data);
$validates = $this->Post->Tag->validates();

$this->Post->set($this->data);
$validates = $validates && $this->Post->validates();

if($validates) {
// Don’t revalidate the Post model because we have already validated earlier
$this->Post->save($this->data, false);
}
}

$this->set(‘tags’, $this->Post->Tag->find(‘list’, array(‘fields’=>array(‘id’, ‘tag’))));
}

This way everything is validated before trying to save, instead of only validating posts when the Tag model validates ok.