How to distinguish 404 between entity doesn't exist and incorrect endpoint?

Question

Using REST principles, 404 seems to be used to indicate that an entity does not exist. However, how can clients distinguish this case from hitting an incorrect endpoint alt

Answer 1

Assuming a framework laid out like this:

/ -- root
|____+
     /object
     |____+
          /members
          |____+
               /attributes
               |____+
                    /attribute_1
                    /attribute_2
                    ...
                    /attribute_n

 
If you mean that you want to be able to distinguish between someone hitting
/object/members/attributes/incorrect_attribute
(a 404 using all the right commands, but attempting to retrieve a non-existent resource)
and someone hitting /object/members/big-bird
(Assuming that members cannot be a valid endpoint on its own
[and that /object/members/attributes is not a valid endpoint either])
then I believe that you could return either a 501 error (not implemented) or a 403 error (Forbidden) depending on where you wanted to place the blame. (Alternately, 418 (I'm a teapot) is also valid here).

EDIT:
Finally, if attribute_n used to exist and no longer does, you could respond with a 410 (resource gone).

See: http://en.wikipedia.org/wiki/List_of_HTTP_status_codes