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Django Standard API Response Middleware for DRF

Author:
agusmakmun
Posted:
December 11, 2019
Language:
Python
Version:
Not specified
Tags:
middleware api django django-rest-framework
Score:
1 (after 1 ratings)

As you can see, if you using django-rest-framework, you will found many different response format. This middleware to solve all of these problems with Standard API Response.

All HTTP Response status stored into json response, not in HTTP Status (because mobile application, like android can't fetch the response body when HTTP Status >= 400).

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# ----------------------------------
# middleware.py
# ----------------------------------

import json
import copy

from django.utils.deprecation import MiddlewareMixin
from django.utils.translation import ugettext_lazy as _
from django.core.serializers.json import DjangoJSONEncoder

from rest_framework import status


class BaseAPIResponseMiddleware(MiddlewareMixin):

    def render_response(self, response):
        """
        function to fixed the response API following with this format:

        [1] success single
            {
             "status": 200,
             "success": true,
             "message": "The success message",
             "result": {}
            }

        [2] success list
            {
               "status": 200,
               "success": true,
               "message": null,
               "results": [],

               "count": 2,
               "page_size": 5,
               "current_page": 1,
               "next": "http://127.0.0.1:8000/api/page/?page=2&search=a",
               "previous": null
            }

        [3] failed
            {
               "status": 400,
               "success": false,
               "message": "The failed message",
               "result": {}
            }
        """
        default_response_keys = ('status', 'status_http', 'detail', 'message',
                                 'success', 'non_field_errors', 'count',
                                 'page_size', 'current_page', 'next',
                                 'previous', 'result', 'results')
        response_data = copy.deepcopy(response.data)

        # setup default result if doesn't exist
        if not any(['result' in response_data, 'results' in response_data]):
            response_data.update({'result': {}})

        # setup default message into response data
        if 'message' not in response_data:
            response_data.update({'message': None})

        # store the status_code into response data
        if 'status' not in response_data:
            response_data.update({'status': response.status_code})

        # store the status_http into response data
        if 'status_http' not in response_data:
            response_data.update({'status_http': response.status_code})

        # updating the response message
        if 'detail' in response_data:
            response_data.update({'message': response_data.get('detail')})
            del response_data['detail']

        elif 'non_field_errors' in response_data:
            response_errors = '<br />'.join(response_data.get('non_field_errors'))
            response_data.update({'message': response_errors})
            del response_data['non_field_errors']

        # store the success boolean into response data
        if response.status_code >= 400:
            response_errors = []
            response_errors_keys = []

            for (key, value) in response_data.items():
                if key not in default_response_keys:
                    errors = ' '.join([str(v) for v in value])
                    errors = '%s: %s' % (key, errors)
                    response_errors.append(errors)
                    response_errors_keys.append(key)

            if len(response_errors) > 0:
                response_errors = '<br />'.join(response_errors)
                response_data.update({'message': response_errors})

            # deleting the errors in the field keys.
            if len(response_errors_keys) > 0:
                list(map(response_data.pop, response_errors_keys))

            if not response_data.get('message'):
                response_data.update({'message': _('Failed')})

            response_data.update({'success': False,
                                  'status_http': status.HTTP_200_OK})

        elif response.status_code >= 100:
            if not response_data.get('message'):
                response_data.update({'message': _('Success')})

            if 'success' not in response_data:
                response_data.update({'success': True})

        return response_data

    def process_response(self, request, response):
        if hasattr(response, 'data') and isinstance(response.data, dict):
            try:
                response_data = self.render_response(response)
                response.status_code = response_data.get('status_http')

                if 'status_http' in response_data:
                    del response_data['status_http']

                response.data = response_data
                response.content = json.dumps(response_data, cls=DjangoJSONEncoder)
            except Exception:
                pass
        return response




# ----------------------------------
# paginator.py
# ----------------------------------

from __future__ import unicode_literals

from collections import OrderedDict

from django.conf import settings
from django.core.paginator import (Paginator, EmptyPage, PageNotAnInteger)
from django.utils.translation import ugettext_lazy as _

from rest_framework import status
from rest_framework.response import Response
from rest_framework.pagination import (PageNumberPagination, LimitOffsetPagination)


class RestPagination(PageNumberPagination, LimitOffsetPagination):
    """
    class FoobarPagiantion(RestPagination):
        page_size = 10


    class FoobarView(ListAPIView):
        pagination_class = FoobarPagiantion
    """

    def paginate_queryset(self, queryset, request, view=None):
        queryset = super().paginate_queryset(queryset, request, view=view)
        limit = request.query_params.get('limit')
        if str(limit).isdigit():
            return queryset[:int(limit)]
        return queryset

    def get_paginated_response(self, results):
        next_link = self.get_next_link() if self.get_next_link() is not None else ''
        prev_link = self.get_previous_link() if self.get_previous_link() is not None else ''

        if settings.USE_SSL:
            next_link = next_link.replace('http:', 'https:')
            prev_link = prev_link.replace('http:', 'https:')

        return Response(OrderedDict([
            ('count', self.page.paginator.count),
            ('page_size', self.page_size),
            ('current_page', self.page.number),
            ('next', next_link if next_link != '' else None),
            ('previous', prev_link if prev_link != '' else None),
            ('status', status.HTTP_200_OK),
            ('message', _('Success')),
            ('success', True),
            ('results', results)
        ]))

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