Django's friends, how many-to-many, better remember User or UserProfile (self) in the field?

Question

I found two ways to implement a symmetric friendship system (you are my friend, so I am also your friend) in Django:

As stated in the docs:

class UserProfile(models.Model): friends = models.ManyToManyField(User, related_name='friends') 

Now I would like to get all the "friendly" user and user models with one similar select_related-query (this should be a reverse combined search):

 profiles = UserProfile.objects.filter(user__in=request.user.get_profile().friends.all()).select_related() 

I request userprofile because this way I can use select_related () and all related objects are cached.

On the other hand, I can determine that my model refers to the friends field as "I", for example:

 class UserProfile(models.Model): friends = models.ManyToManyField('self') 

Now my search related to select_related looks like this:

 profiles = this_user.get_profile().friends.all().select_related() 

I always need both a user object and a profile associated with it. The second approach is much simpler with respect to reverse lookups using select_related (), but almost the same. However, using self as a field link, Django handles symmetrical friendships for me. This way, I do not need to manually create two friendship records in the database. Django does it for me. The symmetric parameter, however, only works with self fields.

What is the best solution? I can do nothing about it. Any ideas appreciated - thanks!

Answer 1

Simon,

Sometimes it’s better to use an existing plugin rather than trying to invent a wheel.

Have you seen django-friends ?