$data = '{ "_id": { "$oid": "59e2ff28da721533d277792c" }, "content" : {"$oid" : "59e2ff28da721533d2777312"} }';
$query = json_decode($data);

$client = new MongoClient("mongodb://username:userpassword@localhost:27017", array("db" => "testdatabase"));
$mDB = $client->testdatabase;
$coll = $mDB->collection_test;
$cursor = $coll->find($query);

$data = '{ "_id": { "$oid": "59e2ff28da721533d277792c" }, "content" : {"$oid" : "59e2ff28da721533d2777312"} }';

$bson = MongoDBBSONfromJSON($data);
$query = MongoDBBSONtoPHP($bson);

$client = new MongoDBDriverManager("mongodb://username:userpassword@localhost:27017/testdatabase");
$filterQuery = new MongoDBDriverQuery($query);
$cursor = $mClient->executeQuery("testdatabase.collection_test", $filterQuery);
return json_encode(iterator_to_array($cursor, false));