serializer.py

class SocialLoginSerializer(UserDeviceMixin, serializers.Serializer):

    PROVIDER_CHOICES = Provider.objects.values_list('name')

    # first_name = serializers.CharField(required=False, allow_blank=True)
    # last_name = serializers.CharField(required=False, allow_blank=True)
    # email = serializers.EmailField()
    # mac_address = serializers.CharField()

    name = serializers.CharField(required=False, allow_blank=True)
    provider_id = serializers.CharField()
    #last_name = serializers.CharField(required=False, allow_blank=True)
    email = serializers.EmailField(required=False, allow_null=True, allow_blank=True)  # twitter does not take "email" filed thts why email filed is null and blank =TRUE
    mac_address = serializers.CharField()
    provider_name = serializers.ChoiceField(
        choices=PROVIDER_CHOICES,
        error_messages={
            'invalid_choice': 'provider_name must be one of the these. {}'.format(", ".join(PROVIDER_CHOICES))
        })

    class Meta:
        fields = '__all__'

    def __init__(self, *args, **kwargs):
        self.auth_fields = None
        self.auth_data = None

        self.provider_fields = None
        self.provider_data = None

        if kwargs.get('data'):
            self.setup_dynamic_fields()

        super().__init__(*args, **kwargs)

    def setup_dynamic_fields(self):
        data = self._kwargs.get('data')
        print(data)
        try:
            provider = Provider.objects.get(name__iexact=data.get('provider_name'))
        except Provider.DoesNotExist:
            msg = 'provider_name must be one of the these. {}'.format(", ".join(SocialLoginSerializer.PROVIDER_CHOICES))
            raise serializers.ValidationError({'provider_name': [msg]})

        provider_settings = ProviderSettings.objects.get(provider=provider.to_dbref())
        #pf = xmltodict.parse(provider_settings.provider_fields)
       # print(pf)

        #data save in db in xml form .... provider fields
        self.auth_fields = xmltodict.parse(provider_settings.auth_fields.strip())

        self.provider_fields = xmltodict.parse(provider_settings.provider_fields.strip())
        for field_name, field_attrs in self.auth_fields['fields'].items():
            field = fields_mapper.get(field_attrs.pop('type'))
            attrs = {}
            if field_attrs.get('required'):
                attrs.update({'required': attr_mapper.get(field_attrs.get('required'))})

            if field_attrs.get('max_length'):
                attrs.update({'max_length': int(field_attrs.get('max_length'))})

            if field_attrs.get('min_length'):
                attrs.update({'min_length': int(field_attrs.get('min_length'))})

            if field_attrs.get('allow_null'):
                attrs.update({'allow_null': attr_mapper.get(field_attrs.get('allow_null'))})

            self.fields[field_name] = field(**attrs)

        for field_name, field_attrs in self.provider_fields['fields'].items():

            field = fields_mapper.get(field_attrs.pop('type'))
            attrs = {}
            if field_attrs.get('required'):
                attrs.update({'required': attr_mapper.get(field_attrs.get('required'))})

            # if field_attrs.get('max_length'):
            #     attrs.update({'max_length': int(field_attrs.get('max_length'))})
            #
            # if field_attrs.get('min_length'):
            #     attrs.update({'min_length': int(field_attrs.get('min_length'))})

            # if field_attrs.get('allow_null'):
            #     attrs.update({'allow_null': attr_mapper.get(field_attrs.get('allow_null'))})

            self.fields[field_name] = field(**attrs)

    def login_user(self):
        data = self.validated_data
        user = authenticate(request=self.context['request'], email=data.get('email'))
        self.auth_data = {field_name: data.get(field_name) for field_name in self.auth_fields['fields']}
        self.auth_data = dict2xml(self.auth_data)

        self.provider_data = {field_name: data.get(field_name) for field_name in self.provider_fields['fields']}
        self.provider_data = dict2xml(self.provider_data)
        print(self.provider_data)

    # def update_provider_fields(self):
    #     data = self.validated_data
    #     print(data)
    #     try:
    #         #provider = Provider.objects.get(name__iexact=data.get('provider_name').lower())
    #         #user_provider = UserProvider.objects.get(user=user.to_dbref(), provider=provider.to_dbref())
    #         provider_settings = ProviderSettings.objects.get(provider_fields=data.provider_fields)
    #         provider_settings.update(provider_fields=self.provider_fields)
    #
    #     except ProviderSettings.DoesNotExist:
    #         print("Error")


        """
        in case user is trying to login with any social site i.e Facebook, Google
        Twitter, we are first checking if user already exist with given email and 
        provider_name (twitter, facebook etc). If exist then do nothing. 
        If user doesn't exist, create a new social user
        """
        if not user:
            user = self.create_user()
        else:
            self.create_or_update_profile(user)

        self.add_user_device(user)
        if not user.token:
            user.token = Token()
            user.save()
        return data

    def create_user(self):
        data = self.validated_data
        user = UserModel(
            first_name=data.get('first_name'),
            last_name=data.get('last_name'))
            # email=data.get('email'))
        user.save()
        self.create_social_profile(user)
        return user

    def create_social_profile(self, user):
        data = self.validated_data
        provider = Provider.objects.get(name__iexact=data.get('provider_name').lower())
        UserProvider.objects.create(
            user=user.to_dbref(),
            provider=provider.to_dbref(),
            user_data=self.provider_data,
            auth_data=self.auth_data
        )

    def create_or_update_profile(self, user):
        data = self.validated_data
        try:
            provider = Provider.objects.get(name__iexact=data.get('provider_name').lower())
            user_provider = UserProvider.objects.get(user=user.to_dbref(), provider=provider.to_dbref())
            user_provider.update(auth_data=self.auth_data)

            user_provider.update(user_data=self.provider_data)

        except UserProvider.DoesNotExist:
            self.create_social_profile(user)