Clarify the JSON response if there are no properties

[aleene]

Problem

Using the read api when no properties are present, I get a NULL as response. This is not very informative. It is unclear if the request succeeded or not. What happened?

Proposed solution

If there are no properties return with json telling that. It might also be possible that there is no product. Unfortunately reading a non-existing product, creates one. So there will always be a product.

Part of

• 🎯 What can I work on ? (Folksonomy Engine) #70