MongoEngine -- how to custom User model / custom backend for authenticate()

Well, looks like the best course of action isn't to hand over Django's User to Mongo for authentication to begin with... Got this golden nugget via Twitter:

@blogblimp my short answer: try to avoid replacing Django user models with MongoDB. You lose all the Django power and lose MongoDB's speed. Seriously, user relates to everything and MongoDB isn't relational.

— Daniel Roy Greenfeld (@pydanny) January 20, 2014

So: I'll just leverage PostgreSQL for authentication, and Mongo for other objects. That means naming / connecting to two databases in the Django settings. In retrospect, I guess the moral is: never use Mongo just because it's cool. Mongo is still a second-class citizen in the Django world.

Maybe I'm a little late, but I could achieve the task of email authentication using mongoengine User + django authenticate, here is how I'm working:

from django.contrib.auth import authenticate, login as do_login, logout as do_logout

def login(request):

    data = extractDataFromPost(request)
    email = data["email"]
    password = data["password"]

    try: 
        user = User.objects.get(username=email)
        if user.check_password(password):
            user.backend = 'mongoengine.django.auth.MongoEngineBackend'
            user = authenticate(username=email, password=password)
            do_login(request, user)
            request.session.set_expiry(3600000) # 1 hour timeout
            return jsonResponse(serializeUser(user)) 
        else:
            result = {'error':True, 'message':'Invalid credentials'}
            return jsonResponse(result) 
    except User.DoesNotExist:
        result = {'error':True, 'message':'Invalid credentials'}
        return jsonResponse(result)