PHP ObjectId group a number of Ids

I have a two collections one of all the people I am following and another of what they have been posting on social networking sites like Twitter and Facebook.

The following collection has a subarray of the _id of the feed collection of each user which each status has the word owner and that has the ObjectId that the owner which is the same as the following key. Here is an example.

'_id' => new MongoId("REMOVED"),
  'following' => 
  array (
    '0' => 'ObjectId("53bf464ee7fda8780c8b4568")',
    '1' => 'ObjectId("53b00ab5e7fda8304b8b4567")',
  ),
  'owner' => new MongoId("53b9ea3ae7fda8863c8b4123"),

and in the feed you will see that the following.0 status below

array (
  '_id' => new MongoId("REMOVED"),
  'owner' => new MongoId("53bf464ee7fda8780c8b4568"),
  'status' => ' love this video - Pedigree Shelter dogs http://youtube.com/watch?v=5v5Ui8HUuN8',
  'timestamp' => new MongoDate(1405044327, 565000),
)

While I can loop through one by one, I can't for some reason do an $or search. I am not quite understanding how I loop through the following array and add it to the search query before I ran the query.

        collection = static::db()->feed;
        $where=array( '$or' => array(array('owner' => new MongoId($following.0)))));
        $feed = $collection->find($where);
        return $feed;

now I understand I will somehow have to loop the $where=array( '$or' => array(array('owner' => new MongoId($following.0))))); But I am just not 100% sure how to do this.

Update

As per the answer below I had to edit the array that was returned - now I have only got this working manually and can't seem to get the PHP script to do it.

Answer Returns

Array ( [owner] => Array ( [$in] => Array ( [0] => new MongoId("53bf464ee7fda8780c8b4568") [1] => new MongoId("53b00ab5e7fda8304b8b4567") ) ) )

Correct:

Array ( "owner" => Array ( '$in' => Array ( "0" => new MongoId("53bf464ee7fda8780c8b4568"), "1" => new MongoId("53b00ab5e7fda8304b8b4567") ) ) )

I am not sure how else to get this to work. current PHP

$collection = static::db()->following;
        $following = $collection->findOne(array ('owner' => new MongoId($_SESSION['user_information'][0]['_id'])));
        $follow = $following['following'];
        
        $collection = static::db()->feed;
        $where=array("owner" => array( '$in' =>$follow));
        print_r($where);
        $feed = $collection->find($where);
        print_r($feed);
        return $feed;

I have fixed a small issue with the collection and now the return array shows

Array ( [owner] => Array ( [$in] => Array ( [0] => MongoId Object ( [$id] => 53bf464ee7fda8780c8b4568 ) [1] => MongoId Object ( [$id] => 53b00ab5e7fda8304b8b4567 ) ) ) )

However, I still can't get it to return the feed like this one:

array (
  '_id' => new MongoId("53bf4667e7fda8700e8b4567"),
  'owner' => new MongoId("53bf464ee7fda8780c8b4568"),
  'status' => ' love this video - Pedigree Shelter dogs http://youtube.com/watch?v=5v5Ui8HUuN8',
  'timestamp' => new MongoDate(1405044327, 565000),
)

Solution

I am presuming here that this is just a PHPism in the way things are displayed and that your following array is an actual array and not a hash/map, which would generally look like this in a JSON representation:

{ 
    "following": [
        ObjectId("53bf464ee7fda8780c8b4568"),
        ObjectId("53b00ab5e7fda8304b8b4567"),
    ],
    "owner": ObjectId("53b9ea3ae7fda8863c8b4123"),
}

In which case the "following" is already an actual array, and if you just want to .find() all the "feed" items for the people you are following, then you just pass that to the $in operator for your query selection:

$where = array( "owner" => array( '$in' => $following ) );
$feed = $collection->find($where);
return $feed;

The returned cursor will only contain results from the feed where the "owner" is present in your "following" array from the other collection item.

Watch this code:

$list = array(new MongoId(), new MongoId, new MongoId());
$doc = array( "owner" => array( '$in' => $list ));


echo json_encode( $doc, JSON_PRETTY_PRINT );

Despite how this serializes for JSON by this method the equivalent JSON is:

{
    "owner": {
        "$in": [
            ObjectId("53bf8157c8b5e635068b4567"),
            ObjectId("53bf8157c8b5e635068b4568"),
            ObjectId("53bf8157c8b5e635068b4569")
        ]
    }
}

That is how the BSON will serialize and is the correct query.