saving data for another model, and problems with redirection, in cakephp

Question

When I save data in one model, I'd like to create some data in another model and save that too. Because I can't do this using beforeSave(), I eventually decided to use afterSave() to create new data items in my second model. I'm not writing a blog application, but to use the blog analogy it's equivalent to automatically creating a series of comments for every blog post that is added and, when a post is edited, deleting all comments and re-adding new comments:

class Post extends AppModel {
    function afterSave() {
        ClassRegistry::init('Comments')->deleteAll(array('Post.id' => $this->id));
        ClassRegistry::init('Comments')->saveAll($comments); // comments contains the comments to be added
    }
}

This works fine, apart from the fact that the afterSave() function causes the redirection from my controller's add/edit actions (to /posts/index) to be overruled, and I get redirected back to the add/edit form instead (if I comment out the entire afterSave() method, the redirection works as intended).

If you're wondering why I didn't put the logic in the controller, I did originally, but I want it to work for both add and edit actions, and also for a "batch" add action I use to add multiple "posts" at once.

I guess I have two questions:

• Is there a better way to achieve this kind of result?

• How can I make the redirection work?

Thanks for reading this far and if I haven't explained it clearly I hope you can use your imagination to see what I'm trying to do.

Answer 1

I think you need to include return true at the end of your afterSave() function. This seems like a decent approach if you don't want to put it in the controller. Although I would think about whether you will always want to add these comments (or whatever they are) after every save, even single-field updates.

Answer 2

In the (somewhat unlikely) event that someone else has the same problem, I eventually found that setting

'atomic' => false

in the saveAll() options solves the problem with the redirect. I have no idea why.

Answer 3

You can't do?:

<?php
function edit_post($id = null) {
    if (!$id && empty($this->data)) {
        // error...
    }       
    if (!empty($this->data)) {
        if ($this->Post->save($this->data)) {
            ClassRegistry::init('Comments')->deleteAll(array('Post.id' => $this->Post->id));
            ClassRegistry::init('Comments')->saveAll($comments); // comments contains the comments to be added
        } else {
            // error...
        }
    }       
    if (empty($this->data)) {
        $this->data = $this->Post->read(null, $id);
    }
}
?>