Validate Json in Django - Django Rest Framework

Question

I need to validate the following JSON:

{
    "monday": [
        //List of MyClass object
    ],
    "tuesday": [
        //List of MyClass Object
    ],
    "wednesday": [
        //List of MyClass Object
    ],
    ......
}

I need to check if it contains any key that is not a day of the week (mondai, thudai for example). Also MyClass is defined as:

class MyClass(models.Model):
    type = models.CharField(unique=True, max_length=20)
    value = models.IntegerField()

The fieldvalue must be a positive integer and cannot exceed 10000. Also, type must be either cost or benefit In Scala I would use the following:

object MyClass {
  val ALLOWED_TYPES = Seq[String]("cost", "benefit")
  implicit val openingHourReads: Reads[OpeningHour] = (
    (JsPath \ "type").read[String].filter(JsonValidationError("Type must be cost or benefit"))(ALLOWED_TYPES.contains(_))  and
      (JsPath \ "value").read[Int](min(1).keepAnd(max(10000)))

    )(MyClass.apply _)

Is there an equivalent approach in Django?

Kha Nguyễn · Accepted Answer · 2020-01-16 05:39:48Z

2

Yes there is a similar approach in django:

Limiting input data on model level (Question#1):

# models.py
from django.core.validators import MaxValueValidator

class MyClass(models.Model):
    VALUE_CHOICES = [
        ('COST', 'cost'),
        ('BENEFIT', 'benefit')
    ]
    class_type = models.CharField(choices=VALUE_CHOICES,unique=True)
    value = models.IntegerField(validators=[MaxValueValidator(limit_value=10000)])

Limiting input data on serializer level (Question#2):

# serializers.py
from .models import MyClass
from rest_framework import serializers
class MyClassSerializer(serializers.ModelSerializer):
    class Meta:
        model = MyClass
        fields = '__all__'

class MainSerializer(serializers.Serializer):
    day = serializers.ChoiceField(choices=['monday', 'tuesday', 'wednesday'])
    my_class = serializers.ListField(child=MyClassSerializer(many=True))

And finally you need to encapsulate your data to make it generic:

# views.py or any other place you like
from .serializers import MainSerializer

your_json = {
    "monday": [
       //List of MyClass object
    ],
    "tuesday": [
        //List of MyClass Object
    ],
    "wednesday": [
        //List of MyClass Object
    ],
    ......
}
json_array = []

for key, value in your_json:
    json_array.append({'day':key, 'my_class':value})

serializer = MainSerializer(data=json_array, many=True)

serializer.is_valid() # this will tell you if your data is valid or not

edited Jan 16, 2020 at 5:39

Kha Nguyễn

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answered Jan 14, 2020 at 19:17

engin_ipek

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4 Comments

Kha Nguyễn Over a year ago

Hi, thank you for helping me. Still, I have another question. Is it possible to validate the JSON field names, I need to check if it contains any key that is not a day of the week (mondai, thudai for example)

engin_ipek Over a year ago

There are serializers in django rest framework. I strongly recommend reading django-rest-framework.org/api-guide/serializers. But your data is not consistent, so rather than trying to validate it through serializers, I would make an array of days and check if the json dictionary's keys are in that array.

Kha Nguyễn Over a year ago

I know the DRF Serializer. However, the JSON does not necessarily contain all days of the week so perhaps Serializer does not work. Looping through the JSON to validate its field seems like a bad practice here.

engin_ipek Over a year ago

Can you check the answer again, hope it helps!

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Validate Json in Django - Django Rest Framework

1 Answer 1

Limiting input data on model level (Question#1):

Limiting input data on serializer level (Question#2):

And finally you need to encapsulate your data to make it generic:

4 Comments

Your Answer

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Collectives™ on Stack Overflow

1 Answer 1

Limiting input data on model level (Question#1):

Limiting input data on serializer level (Question#2):

And finally you need to encapsulate your data to make it generic:

4 Comments

Your Answer

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