Services 3 Output alter hook Are there any hooks to alter the Services modules output. 
For eg : If I get a result like this for a file object. 

{
  "fid": "132",
  "uri": "public:\/\/512dab4918036.jpg",
  "filename": "512dab4918036.jpg",
  "filemime": "image\/jpeg",
  "uid": "1",
  "status": 1,
  "timestamp": 1361947464,
  "filesize": 2521,
}


I want to limit it for users with certain roles. 

I am looking for this as I have made many services resource manually so I don't want to edit them all and simply use the output alter hook to do something. 

Is it possible ?
The available hooks for Services are documented in the api docs for services

You probably want hook_services_request_postprocess_alter($controller, $args, $result); which allows you to change the array of $result any way you want.