Fix error when clients have no associated user

[rocha]

The user field of the Client model is mark as nullable. However, during
serialization it is expected to be a dictionary, throwing an
error.

Fixed by checking if the user is None and serializing as null.

[clintonb]

@eculver @andy-a @devioustree @JJSaccolo @saschoar Is this project still maintained? There have been no commits for over six months, despite numerous pull requests.

[eswenson1]

@clintonb Did you ever get any response to your question of Sep 22, 2014? Should someone else take over this project? I also need this fixed and have fixed on my own fork, but this project does seem stagnant. Since django-oauth2-provider is the recommended OAuth2 framework by django-rest-framework, this really should get one or more active maintainers.

[clintonb]

@eswenson1 I never received a response.

[eswenson1]

@clintonb Thanks. It looks that there are others frustrated by lack of support and merging of PRs. I've seen references (in tickets and PRs) of others taking over the project. I'll see if I can track down anyone who is interested.

[blag]

@eswenson1, @clintonb: As I've mentioned elsewhere, the two most active forks are @mapmyfitness (here) and @glassresistor (here).

This upstream appears to be dead.