HABTM Find with CakePHP 2.0 - cakephp

Question

I am trying to do a search, using pagination for posts which have a specific tag or tags (for example, if a user was to select two tags, then posts containing either tag would be returned).
I have the relationship defined in my Posts table
public $hasAndBelongsToMany = array('Tags' => array(
'className' => 'Tags',
'joinTable' => 'posts_tags',
'foreignKey' => 'post_id',
'associationForeignKey' => 'tag_id',
'unique' => 'keepExisting'));
How do I use Find to retrieve rows with a given tag (name or ID would be fine)
Trying:
// other pagination settings goes here
$this->paginate['conditions']['Tags.id'] = 13;
gives me an error that the relationship does not exist.
Looking at the debug info it appears that the tables are not joining the Posts_Tags and Tags table, however, when I debug the data making it to the view, the Posts objects contain the tags data.
Most of the documentation I can find for this seems to revolve around earlier versions of CakePHP, any help would be appreciated.

Answer 1

Could not find a satisfying solution myself.
I created a behavior to take care of this.
Create a file called HabtmBehavior.php and put it in your app/Model/Behavior folder.
Put the block of code in there and save file.
Add the behavior to your model: eg public $actsAs = array('Habtm');
Here is a usage example with find.
<?php $this->Entry->find('all', array('habtm'=>array('Tag'=>array('Tag.title'=>'value to find'))) ?>
Paginate would look something like this:
$this->paginate['Entry']['habtm']['Tag'] = array('Tag.title'=>'value to find');
You are free to add as many relations as you want by adding additional Model Names in the habtm array.
(Just be careful not to make it to complex since this could start slowing down your find results.)
<?php
class HabtmBehavior extends ModelBehavior {
public function beforeFind(Model $model, $options) {
if (!isset($options['joins'])) {
$options['joins'] = array();
}
if (!isset($options['habtm'])) {
return $options;
}
$habtm = $options['habtm'];
unset($options['habtm']);
foreach($habtm as $m => $scope){
$assoc = $model->hasAndBelongsToMany[$m];
$bind = "{$assoc['with']}.{$assoc['foreignKey']} = {$model->alias}.{$model->primaryKey}";
$options['joins'][] = array(
'table' => $assoc['joinTable'],
'alias' => $assoc['with'],
'type' => 'inner',
'foreignKey' => false,
'conditions'=> array($bind)
);
$bind = $m.'.'.$model->{$m}->primaryKey.' = ';
$bind .= "{$assoc['with']}.{$assoc['associationForeignKey']}";
$options['joins'][] = array(
'table' => $model->{$m}->table,
'alias' => $m,
'type' => 'inner',
'foreignKey' => false,
'conditions'=> array($bind) + (array)$scope,
);
}
return $options;
}
}
Hope this helps.
Happy baking.

Answer 2

I think the best solution is apply find function on join table Model. I try this before and it's work fine.
in your PostTag model :
/**
* #see Model::$actsAs
*/
public $actsAs = array(
'Containable',
);
/**
* #see Model::$belongsTo
*/
public $belongsTo = array(
'Post' => array(
'className' => 'Post',
'foreignKey' => 'post_id',
),
'Tags' => array(
'className' => 'Tag',
'foreignKey' => 'tag_id',
),
);
in your controller :
// $tagsId = tags ids
$posts = $this->PostTag->find('all', array('conditions' => array('PostTag.tag_id' => $tagsId),'contain' => array('Post')));
also is better follow cake naming convention, if you have tags(plural), post_tags(first singular second plural),posts(plural) tables you must have Tag,PostTag,Post Models.