Django 序列化程序：未调用验证函数

Question

I am trying override validate() function to be called by serializers.is_valid() , but its not getting called.

serializer.py

class LoginSerializer(serializers.Serializer):
    email = serializers.EmailField(max_length=255,required=True)
    password = serializers.CharField(max_length=128,required=True)


    def validate(self,data):
       '''
       Check for invalid email.
       & blank email and password. 
       '''

       print 'hey i am in login'

       if data['email'] is '':
           raise serializers.ValidationError("Email cannot be empty.")
       if data['password'] is '':
          raise serializers.ValidationError("Password cannot be empty.")
       try:
          validate_email(data['email'])
       except ValidationError:
          raise serializers.ValidationError("The email is not a valid email address.")
       return data

views.py

class LoginAPI(APIView):
    permission_classes = (permissions.AllowAny,)
    serializer = LoginSerializer

    def post(self, request):
       data = self.serializer(data=request.data)
       if data.is_valid():
          #do something
       else:
           return Response(data.errors,status=status.HTTP_400_BAD_REQUEST)

while i call is_valid() , the print statement inside validate() function is not getting executed. what am i doing wrong?

Answer 1

I think you are not getting any print statements because validate function is not being called.

If there is an error in one of the fields say email , validate function won't be called but since you didn't pass raise_exception=True as argument in is_valid you are not getting those errors and you assume that is_valid is not running.

You could write the post method as following:

def post(self, request):
   serializer = self.serializer(data=request.data)

   # following will automatically raise an exception if the serialize data is not valid
   serializer.is_valid(raise_exception=True)

   # do something if the serializer is valid

UPDATE : If you want to raise specific message after validating different fields, you could create a method validate_<fieldname> in serializer:

def validate_email(self, value):

    if value == '':
        raise serializers.ValidationError("Email cannot be empty.")

    try:
        validate_email(value)
    except ValidationError:
        raise serializers.ValidationError("The email is not a valid email address.")

    return value

Answer 2

I had the same error. Try to go with

def run_validation(self, data):
...

instead of

def validation(self, data):
...

this should work!