Django如何从ManyToManyField进行序列化并列出全部 [英] Django How to Serialize from ManyToManyField and List All
问题描述
我正在使用Django 1.9.1开发移动应用程序后端，我实现了关注者模型，现在我想列出用户的所有关注者，但是我目前仍坚持这样做.我也使用Django Rest Framework.
I'm developing a mobile application backend with Django 1.9.1 I implemented the follower model and now I want to list all of the followers of a user but I'm currently stuck to do that. I also use Django Rest Framework.
这是我的UserProfile模型
This is my UserProfile model
class UserProfile(models.Model):
# Linking UserProfile to User model.
user = models.OneToOneField(User)
city = models.CharField(null=True, max_length=30, blank=True)
gender = models.CharField(null=True, max_length=10, blank=True) # m for male, f for female
# TODO: Fix the picture later.
# picture = models.ImageField(upload_to='profile_images', blank=True)
age = models.IntegerField(null=True, blank=True)
caption = models.CharField(null=True, max_length=40, blank=True)
following_count = models.IntegerField(default=0)
follower_count = models.IntegerField(default=0)
post_count = models.IntegerField(default=0)
like_count = models.IntegerField(default=0)
date = models.DateTimeField(default=datetime.now(), blank=True)
is_protected = models.BooleanField(default=False)
is_facebook_created_user = models.BooleanField(default=False)
facebook_id = models.CharField(default='', blank=True, max_length=350)
picture_url = models.URLField(blank=True, max_length=100, null=True)
followings = models.ManyToManyField('self', related_name='following', symmetrical=False)
followers = models.ManyToManyField('self', related_name='follower', symmetrical=False)
blocking = models.ManyToManyField('self', related_name='block', symmetrical=False)
blocked_by = models.ManyToManyField('self', related_name='blocked', symmetrical=False)
def block_user(self,username):
other = UserProfile.objects.get(user__username=username)
if not self.is_blocking(username):
self.blocking.add(other)
other.blocked_by.add(self)
return True
else:
return False
def unblock_user(self, username):
other = UserProfile.objects.get(user__username=username)
if self.is_blocking(username):
self.blocking.remove(other)
other.blocked_by.remove(self)
return True
else:
return False
def follow_user(self, username):
other = UserProfile.objects.get(user__username=username)
if not self.is_following(username):
self.followings.add(other)
self.following_count = self.followings.all().count()
self.save()
other.followers.add(self)
other.follower_count = other.followers.all().count()
other.save()
return True
else:
return False
def unfollow_user(self, username):
other = UserProfile.objects.get(user__username=username)
if self.is_following(username):
self.followings.remove(other)
self.following_count = self.followings.all().count()
self.save()
other.followers.remove(self)
other.follower_count = other.followers.all().count()
other.save()
return True
else:
return False
def is_blocking(self,username):
return self.blockings.all().filter(user__username=username).exists()
def is_blocked_by(self,username):
return self.blocked_by.all().filter(user__username=username).exists()
def is_following(self, username): #returns Bool
return self.followings.all().filter(user__username=username).exists()
def is_followed_by(self, username): #returns Bool
return self.followers.all().filter(user__username=username).exists()
def __unicode__(self):
return self.user.username
def get_token(self):
try:
token = Token.objects.get(user_id=self.user_id)
except:
token = 'error'
return token
def get_username(self):
return self.user.username
如您所见，我将ManyToManyField用于关注者.现在，我想列出一个用户的关注者，但是我不想只列出他们的所有信息，因为这是不必要的.我只想列出他们的用户名，因为不需要完整的信息，这只是浪费.
As you see, I user ManyToManyField for followers. Now I want to list followers of a user but I don't want to list just all of their information since it's unnecessary. I just want to list their usernames because no need for whole information and it's just a waste.
这是我的关注者视图.
@api_view(['GET'])
def get_followers(request):
username = request.query_params.get('username', None)
if username is not None:
if UserProfile.objects.all().filter(user__username=username).exists():
wanted = UserProfile.objects.get(user__username=username)
followers = wanted.followers.all()
serializer = FollowerSerializer(followers)
return JsonResponse(serializer.data)
else:
return JsonResponse({"result": "user_does_not_exist"})
else:
#TODO: return current user's followers
return JsonResponse({"result": "provide_username"})
我还添加了仅针对用户关注者的序列化器.
Also I added a serializer for only followers of user.
class FollowerSerializer(serializers.ModelSerializer):
class Meta:
model = UserProfile
field = ('followers',)
问题是，它仅列出所有用户信息，并且不提供用户名，而仅列出其ID，而我却无能为力.
The problem is, it just lists the all of the user information and it doesn't give usernames but it only lists their id's which i can't do anything.
我忘了提到我确实考虑过使用ListAPIView，但是我不能用它来获取username参数.如果有一种获取参数的方法，我也可以将ListAPIView用于关注者.
I forgot to mention that I did think of using ListAPIView but I can't get the username parameter with that. If there is a way of getting the parameter, I could also use ListAPIView for followers.
如何解决此问题并仅列出其用户名?任何帮助将不胜感激.
How can I fix this problem and list only their usernames? Any help will be appreciated.
推荐答案
我认为您需要的是嵌套的序列化器:
I think what you need is the nested serializer:
class FollowerSerializer(serializers.ModelSerializer):
username = serializers.CharField(source='user__username')
class Meta:
model = UserProfile
fields = ('username', )
class FollowerSerializer(serializers.ModelSerializer):
followers = FollowerSerializer(many=True, read_only=True)
class Meta:
model = UserProfile
fields = ('followers', )
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