In conduit applications, I can search for my subscribed phame blogs by adding constraints as follows. The following curl does only list phame blogs that user huangsj subscribes to.
```
curl http://mso.yidian-inc.com/api/phame.blog.search \
-d api.token=api-token \
-d constraints[subscribers][0]=huangsj
```
But when I write php code, I don't know how to specify constraints.
I modify PhameBlogSearchEngine.php as follows. However, the "subscribed" query shows all blogs instead of those subscribed by huangsj
```
public function buildSavedQueryFromBuiltin($query_key) {
$query = $this->newSavedQuery();
$query->setQueryKey($query_key);
$viewer_username = $this->requireViewer()->getUsername();
switch ($query_key) {
case 'all':
return $query;
case 'subscribed':
$query->setParameter('constraints', array('subscribers' => array($viewer_username)));
return $query;
```
What is the equivalent php code to that of curl?