[英]Django How to Serialize from ManyToManyField and List All
我正在使用Django 1.9.1開發移動應用程序后端我實現了跟隨者模型,現在我想列出用戶的所有關注者,但我現在仍然堅持這樣做。 我也使用Django Rest Framework。
這是我的UserProfile模型
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
如您所見,我為追隨者使用ManyToManyField。 現在我想列出用戶的關注者,但我不想列出他們所有的信息,因為這是不必要的。 我只想列出他們的用戶名,因為不需要整個信息,這只是浪費。
這是我的粉絲觀點。
@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"})
我還為只有用戶的粉絲添加了一個序列化程序。
class FollowerSerializer(serializers.ModelSerializer):
class Meta:
model = UserProfile
field = ('followers',)
問題是,它只是列出了所有的用戶信息,並沒有給出用戶名,但它只列出了我無法做任何事情的id。
我忘了提到我確實想過使用ListAPIView,但我無法獲得用戶名參數。 如果有辦法獲取參數,我也可以使用ListAPIView作為關注者。
如何解決此問題並僅列出其用戶名? 任何幫助將不勝感激。
我認為你需要的是嵌套的序列化器:
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', )
我在這個鏈接中使用了嵌套關系。 Django Rest框架嵌套關系
僅為用戶的用戶名添加了新的序列化程序,並且還更改了其他序列化程序。
# serializes only usernames of users
class EachUserSerializer(serializers.ModelSerializer):
username = serializers.CharField(source='user.username')
class Meta:
model = UserProfile
fields = ('username',)
class FollowerSerializer(serializers.ModelSerializer):
followers = EachUserSerializer(many=True, read_only= True)
followings = EachUserSerializer(many=True,read_only=True)
class Meta:
model = UserProfile
fields = ('followers','followings')
輸出正是我所尋找的:
{ "followers": [], "followings": [ { "username": "sneijder" }, { "username": "drogba" } ] }
謝謝你的幫助:)
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