drf

Question 1

what a router does is

Answer 1

generates the url patterns for the viewsets you register to it, and gives you an object to throw into urls.py

goes in stub folder
project_name/project_name/router.py

from rest_framework import routers
from app_name.api.viewsets import *

router = routers.DefaultRouter()
router.register(r’model_name’, RatingViewSet, ‘model_name’)

Question 2

a viewset is

Answer 2

a class in which you define the actions and serializers you want to use, or use ModelViewSet to just set the serializer and and queryset and all the functions from the router will be injected.

note: when setting the queryset, dont use an underscore query_set.

in app_name/api/viewsets.py

from app_name.models import ModelName
from .serializers import ModelnameSerializer
from rest_framework import viewsets
from rest_framework import permissions

class ModelNameViewSet(viewsets.ModelViewSet):
    permission_classes = (permissions.IsAuthenticatedOrReadOnly,)
    queryset = Modelname.objects.all()
    serializer_class = ModelNameSerializer

Question 3

to use request.user in the viewset, type

Answer 3

Overwrite the queryset property with a custom function

class ModelNameViewSet(viewsets.ModelViewSet):
    permission_classes = (permissions.IsAuthenticatedOrReadOnly,)
    serializer_class = ModelNameSerializer

    def get_queryset(self):
        user = self.request.user
        return ModelName.objects.filter(user=user)

Question 4

a serializer is

Answer 4

a class that defines how to convert an object to a key, value dictionary. It’s a lot like a form, and can perform validations

class ModelNameSerializer(serializers.Serializer):
    field_1 = serializers.EmailField(required=False)#makes optional
    field_2 = serializers.CharField(max_length=200)
    def validate_field_1(self, field_value):
        if field_value < 1:
            raise serializers.ValidationError("string")
        return field_value

or to skip the field definitions and use the defaults from the model

from rest_framework import serializers
from app_name.models import ModelName

class ModelNameSerializer(serializers.ModelSerializer):
    class Meta:
        model = ModelName
        fields = ('field_1', 'field_2',) # or just "\_\_all\_\_"

Question 5

To add a custom computed field to a serializer

Answer 5

add a function to your model

then add to serializer

class ModelNameSerializer(serializers.Serializer):
    new_function = serializers.ReadOnlyField()
    class Meta:
        model = ModelName
        fields = ('new_function',)

or maybe for foreign keys

class ModelNameSerializer(serializers.ModelSerializer):
    custom_field = serializers.ReadOnlyField(source="foreign_key_field.field")
    class Meta:
        model = ModelName
        fields = ('field_1', 'custom_field',)

Question 6

good tutorial

Answer 6

https://www.youtube.com/watch?v=riZYgLOYq4g&t=562s

Question 7

to have nested objects inside a serializer

Answer 7

https://stackoverflow.com/questions/14938895/serializer-dealing-with-nested-objects

and to have them nested but with a reverse relationship list of objects
https://stackoverflow.com/questions/14573102/how-do-i-include-related-model-fields-using-django-rest-framework

Question 8

to create a serializer that loads in related objects (that have a forward relationship, aka, they contain the field=models.ForeignKey()) as nested dictionaries, type

Answer 8

class ModelNameSerializer(serializers.ModelSerializer):
    class Meta:
        model = ModelName
        depth = 1

Question 9

to serialize a related foreign key object

Answer 9

name the field in the serializer the same as the foreign key field name, and set the value to the serializer you want to use for the related element.

class RelatedModelSerializer(serializers.ModelSerializer):
    class Meta:
        model = RelatedModel
        fields = ('field_1', 'field_2')

class ProductSerializer(serializers.ModelSerializer):
    related_field_name = RelatedModelSerializer()

    class Meta:
        model = Product
        fields = ('field_1', 'field_2', 'related_field_name')

Question 10

notes

Answer 10

from rest_framework import routers
from noot.api.viewsets import *

router = routers.DefaultRouter()
# router.register(r'ratings', RatingViewSet, 'ratings')

# this generates a list of url() pattern objects and passes them into the urls.py (just creates /object_name/ and /object_name/id/ because the actions are chosen with http method)
# the first argument is the prefix of the url pattern definition/namespace
# The router uses the queryset defined in the viewset to determine the base_name 
# base_name is the prefix it will use for names in the url(..., name='string') definitions. Becomes url(..., name='prefix_base_name_string')
# rest of the name will be the filled with the generated view types: base_name-list, base_name-detail from the viewset
# using a routers prevents you from needing to write your own url patterns
# https://stackoverflow.com/questions/46053922/delete-method-on-django-rest-framework-modelviewset
# To hit the different actions, you need to use the right http method. list:get, create:post, retrieve:get, update:put, partial_update:patch, destroy:delete.
# router makes these automatically

url(r'^api/', include(router.urls)), # this allows you to add additional urls by registering them to router

from rest_framework import serializers
from noot.models import Rating

# class RatingSerializer(serializers.ModelSerializer):
#     class Meta:
#         model = Rating
#         fields = ('noot', 'rating', 'user', 'pk')

from noot.models import Rating
# from .serializers import RatingSerializer
from rest_framework import viewsets

# class RatingViewSet(viewsets.ModelViewSet):
#     queryset = Rating.objects.all()
#     serializer_class = RatingSerializer

# the attributes set in this ModelView class are just there to be used by all the later functions
# many of these functions are invisible because they are inherited from parent class
# if you use a modelviewset instead of viewset, it adds the methods the router generated routes for: list, create, retrieve, update, partial_update, delete
# otherwise you need to define these functions yourself

Question 11

To serialize a qs and have a nested field thats a reverse relationship

Answer 11

class ModelNameSerializer(serializers.ModelSerializer):
    model_name_set = ReverseRelatedModelNameSerializer(read_only=True, many=True, source='model_name_set')
    class Meta:
        model = Cart
        depth = 1
        fields = (
            'field_1', 
            'field_2', 
            'model_name_set', 
        )

Question 12

To make a user pass a test or otherwise redirect for function based views

Answer 12

https://stackoverflow.com/questions/8082670/django-user-passes-test-decorator

Question 13

To create custom rest framework permission

Answer 13

https://www.youtube.com/watch?v=-0c88d24qzM

Question 14

To add a function decorator to a class based views methods

Answer 14

https://stackoverflow.com/questions/8082670/django-user-passes-test-decorator

Question 15

under the hood, the generated code for the list function in a viewset is

Answer 15

def list(self, request);
    queryset = ModelName.objects.all()
    serializer = ModelNameSerializer(queryset, many=True)
    return Response(serializer.data)

Question 16

to make a custom view in a modelviewset, type

Answer 16

Note: This assumes I already set the queryset and serializer on the class
@action(methods=["GET"], detail=False) #this means dont listen of the detail url
def newest(self, request):
    newest = self.get_queryset().first()
    serializer = self.get_serializer_class()(newest)
    return Response(serializer.data)

Question 17

detail=True in a custom view inside a viewset is for

Answer 17

telling it to listen to requests on the detail url or the list url

ie item/ or item/1/

seems that self.get_object() on an action with detail=True inserts the url id ad the id filter on the queryset.

@action(detail=True, methods=['post'])
def set_password(self, request, pk=None):
    user = self.get_object()
    serializer = PasswordSerializer(data=request.data)
    if serializer.is_valid():
        user.set_password(serializer.data['password'])
        user.save()
        return Response({'status': 'password set'})
    else:
        return Response(serializer.errors,
                        status=status.HTTP_400_BAD_REQUEST)

Question 18

to add a custom permission to a custom view in a viewset, type

Answer 18

@action(detail=False, methods=[‘post’], permission_classes=[IsAdminOrIsSelf])

Question 19

To make objects only edittable by their owners you need to

Answer 19

create a custom permission like this.

https://stackoverflow.com/questions/50646966/django-rest-framework-related-model-permissions

Question 20

js: To import a member export and default export in the same line, type

Answer 20

import DefaultExport, { MemberExport } from ‘package’;

Question 21

vscode: To format the document, type

Answer 21

command + shift + p
type format
enter

Question 22

to validate two fields are unique together, type

Answer 22

class Show(models.Model):
   day = models.ForeignKey(TimeTable, related_name='show')
   time = models.TimeField(choices=CHOICE_TIME)
   movie = models.ForeignKey(Movie)

class Meta:
    unique_together = ('day', 'time')

Question 23

To filter in a viewset without overwriting def get_queryset(self), use

Answer 23

pip install django-filter, installed apps ‘django_filters’

http://url.com?ordering=-field_1,field_2,field_1&field_3=True

add to ViewSet

filter_backends
= (django_filters.rest_framework.DjangoFilterBackend, )
filter_fields = (‘field_1’, ‘field_2’) #allowed filter get params
search_fields = (‘field_1’,) #uses partial match on all fields
ordering_fields = (‘field_1’, ‘field_2’) #allowed sort fields
ordering = (‘field_1’,) #optional default ordering

or

from django_filters import rest_framework as filters

class ModelNameFilter(filters.FilterSet):
    field_1 = filters.NumberFilter(field_name='models_field_name', lookup_expr='gte')
    max_price = filters.NumberFilter(field_name='models_field_name', lookup_expr='lte')
    start_date = filters.DateFilter(field_name='date', lookup_expr='lt')
    end_date = filters.DateFilter(field_name='date_joined', lookup_expr='gt')

    class Meta:
        model = ModelName
        fields = ['field_1', 'field_2', 'min_price', 'max_price']

add to viewset
filter_class = ModelNameFilter

https://stackoverflow.com/questions/47220070/django-rest-framework-filtering-by-datetime

Question 24

A filter class is

Answer 24

a class that defines the permitted get parameters that will return filtered querysets.

import django_filters

class ModelNameFilter(django_filters.FilterSet):
    class Meta:
        model = ModelName
        fields = {
            'field_1': ['icontains'],
            'field_2': ['icontains'] 
        }

https://www.youtube.com/watch?v=nle3u6Ww6Xk&t=215s

Question 25

The most basic example of DRF is

Answer 25

from rest_framework import routers, viewsets, serializers
from debate.models import ModelName

class ModelNameSerializer(serializers.ModelSerializer):
    class Meta:
        fields = "\_\_all\_\_"
        model = ModelName

class ModelNameViewSet(viewsets.ModelViewSet):
    queryset = ModelName.objects.all()
    serializer_class = ModelNameSerializer

router = routers.DefaultRouter()
router.register(model_name’, ModelNameViewSet)

urlpatterns = [
url(r’^api-auth/’, include(‘rest_framework.urls’)),
url(r’^api/’, include(router.urls)),
]

Question 26

to get great python features, learn this.

Answer 26

https://www.youtube.com/watch?v=CZ8bZPqtwU0&index=2&list=PLP8GkvaIxJP0VAXF3USi9U4JnpxUvQXHx