Thanks a lot for your help! It is working perfectly.
I used 2 question marks because the reference here used a question mark before "stream".
Please bear with me if this is a silly question, but it has been on my mind for a while.
When shall I use question mark and when shall I use & sign in a query?
The query is separated by the ? from the path. Inside a query can be numerous key=value-pairs which are separated by &. That's basically it.
I strongly suggest you take some time to get deeper into the HTTP-thing as you will have to deal with it more often when using the REST apis. Maybe start here: http://code.tutsplus.com/tutorials/http-the-protocol-every-web-developer-must-know-part-1--net-31177