DRF Friendly Errors

Extension for Django REST framework error display

Overview

This package extends default error JSON body providing configurable error codes and more consumable response structure.

It turns default JSON body of HTTP 400 response, which look like this

{
    "name": ["This field is required."],
    "password": ["This field may not be blank."]
}

into

{
    "errors": {
        "name": [
            {
                "message": "This field is required."
                "code": "required"
            }
        ],
        "password": [
            {
                "message": "This field may not be blank."
                "code": "blank"
            }
        ]
    }
}

Library handles all Django REST framework built-in serializer validation.

Requirements

Python (2.7, 3.5, 3.6)
Django (1.10+, 1.11+)
Django REST framework (>=3.3)

Installation

By running installation script

$ python setup.py install

Or using pip

$ pip install drf-friendly-errors

Usage

Simply add a FriendlyErrorMessagesMixin to your serializer or model serializer class

from rest_framework_friendly_errors.mixins import FriendlyErrorMessagesMixin

class MySerializer(FriendlyErrorMessagesMixin, ModelSerializer):

If you want to change default library settings and provide your own set of error codes just add following in your settings.py

FRIENDLY_ERRORS = {
    FIELD_ERRORS = {
        'CharField': {'required': 'my_custom_error_code', 'null': 'my_custom_error_code'}
    }
    VALIDATOR_ERRORS = {
        'UniqueValidator': 'my_custom_error_code'
    },
    EXCEPTION_DICT = {
        'PermissionDenied': 'my_custom_error_code'
    }
}

Custom serializer validation

If you need custom field validation or validation for whole serializer register your validation in serializer class

class PostSerializer(FriendlyErrorMessagesMixin,
                     serializers.ModelSerializer):
    class Meta:
        model = Post

    def validate_title(self, value):
        if value[0] != value[0].upper():
            raise ValidationError('First letter must be an uppercase')
        return value

    def validate(self, attrs):
        category = attrs.get('category)
        title = attrs.get('title')
        if category and category not in title:
            raise ValidationError('Title has to include category')
        return attrs

    FIELD_VALIDATION_ERRORS = {'validate_title': 'invalid_title'} # register your own validation method and assign it to error code
    NON_FIELD_ERRORS = {'Title has to include category': 'no_category'} # register non field error messages and assign it to error code

If you want to raise field error in validate method use register_error method provided by a mixin

class PostSerializer(FriendlyErrorMessagesMixin,
                     serializers.ModelSerializer):
    class Meta:
        model = Post

    def validate(self, attrs):
        category = attrs.get('category')
        title = attrs.get('title')
        if category and category not in title:
            self.register_error(error_message='Title has to include category',
                                error_code='no_category',
                                field_name='title')
        return attrs

Error codes not related to serializer validation

To turn other type of errors responses into friendly errors responses with error codes add this exception handler to your REST_FRAMEWORK settings

REST_FRAMEWORK = {
    'EXCEPTION_HANDLER':
    'rest_framework_friendly_errors.handlers.friendly_exception_handler'
}

Tests

Make sure your tests are passing for pull request. You can run the test suite with:

python runtests.py

Contributors

Geoffrey Lehée <socketubs>
Aamir Rind <intellisense>

awaazde/drf-friendly-errors