akshar-raaj

This post is targetted towards Celery beginners. It discusses different ways to run Celery.

• Using celery with a single module
• Using celery with multiple modules.
• Using celery with multiple modules split across packages.

Prerequisites

You should have Celery and Redis installed. We will use Redis as our broker.

akshar-raaj

class UserSerializer(serializers.ModelSerializer):

    def validate_password(self, value):
        if value.isalnum():
            raise serializers.ValidationError('password must have atleast one special character.')
        return value

    def validate(self, data):
        if data['first_name'] == data['last_name']:
            raise serializers.ValidationError("first_name and last_name shouldn't be same.")

akshar-raaj

class Question(models.Model):
    question_text = models.CharField(max_length=200)
    pub_date = models.DateTimeField('date published', null=True)
    author = models.CharField(max_length=200, null=True)

    def __str__(self):
        return self.question_text

class Choice(models.Model):
    question = models.ForeignKey(Question, on_delete=models.CASCADE)

akshar-raaj

class UserSerializer(serializers.ModelSerializer):

    class Meta:
        model = User
        fields = ('email', 'first_name', 'last_name')

    def to_representation(self, instance):
        representation = super().to_representation(instance)
        if instance.is_superuser:
            representation['admin'] = True

akshar-raaj

class UserSerializer(serializers.ModelSerializer):

    def validate_password(self, value):
        if value.isalnum():
            raise serializers.ValidationError('password must have atleast one special character.')
        return value

    class Meta:
        model = User
        fields = ('username', 'email', 'first_name', 'last_name', 'password')

akshar-raaj

Question.objects.values('question_text').annotate(cnt=Count('question_text'))

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Question.objects.annotate(avg_votes=Avg('choice__votes'))

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Choice.objects.aggregate(avg=Avg('votes'))

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Choice.objects.aggregate(num_votes=Sum('votes'))

akshar-raaj

Question.objects.annotate(num_votes=Sum('choice__votes')).filter(num_votes__isnull=True)