Custom serializer fields in Django - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to define a custom serializer field that converts a value to uppercase.

Django

from rest_framework import serializers

class UpperCaseField(serializers.Field):
    def to_representation(self, value):
        return value.[1]()

Drag options to blanks, or click blank then click option'

Aupper

Blower

Ccapitalize

Dtitle

Attempts:

3 left

💡 Hint

Common Mistakes

Using lower() instead of upper()

Forgetting the parentheses after the method name

The to_representation method converts the value to uppercase using the upper() string method.

2fill in blank

medium

Complete the code to convert the input data to lowercase in the custom serializer field.

Django

class LowerCaseField(serializers.Field):
    def to_internal_value(self, data):
        return data.[1]()

Drag options to blanks, or click blank then click option'

Acapitalize

Blower

Cstrip

Dtitle

Attempts:

3 left

💡 Hint

Common Mistakes

Using capitalize() which only changes the first letter

Using strip() which removes whitespace

The to_internal_value method processes input data. Using lower() converts the string to lowercase.

3fill in blank

hard

Fix the error in the custom field to correctly raise a validation error when input is not a string.

Django

from rest_framework import serializers

class StringField(serializers.Field):
    def to_internal_value(self, data):
        if not isinstance(data, str):
            raise serializers.[1]('Expected a string')
        return data

Drag options to blanks, or click blank then click option'

APermissionDenied

BParseError

CNotFound

DValidationError

Attempts:

3 left

💡 Hint

Common Mistakes

Using exceptions meant for HTTP errors like NotFound or PermissionDenied

Using ParseError which is for parsing issues

To signal invalid input in serializers, raise serializers.ValidationError.

4fill in blank

hard

Fill both blanks to create a custom field that converts a datetime object to ISO format string and parses it back.

Django

import datetime
from rest_framework import serializers

class ISODateTimeField(serializers.Field):
    def to_representation(self, value):
        return value.[1]()

    def to_internal_value(self, data):
        return datetime.datetime.[2](data)

Drag options to blanks, or click blank then click option'

Aisoformat

Bfromisoformat

Cstrftime

Dstrptime

Attempts:

3 left

💡 Hint

Common Mistakes

Using strftime and strptime without correct format strings

Mixing up the method names

isoformat() converts datetime to ISO string. fromisoformat() parses ISO string back to datetime.

5fill in blank

hard

Fill all three blanks to create a custom serializer field that validates an integer is positive and returns it.

Django

from rest_framework import serializers

class PositiveIntegerField(serializers.Field):
    def to_internal_value(self, data):
        value = int(data)
        if value [1] 0:
            raise serializers.ValidationError('[2] must be positive')
        return value

    def to_representation(self, value):
        return [3]

Drag options to blanks, or click blank then click option'

A<=

BValue

Cvalue

D<

Attempts:

3 left

💡 Hint

Common Mistakes

Using '<' instead of '<=' causing zero to pass

Using lowercase 'value' in error message

Returning data instead of value in to_representation

The code checks if value <= 0 to raise an error. The error message uses 'Value'. The to_representation returns the integer value.