DRF Tutorial

DRF Tutorial
Author

Benedict Thekkel

Getting started

mkdir tut_drf2
python3 -m venv env
source env/bin/activate
pip install django
pip install djangorestframework
pip install pygments  # We'll be using this for the code highlighting
django-admin startproject tut2
cd tut2
python manage.py startapp snippets

tutorial/settings.py

edit

INSTALLED_APPS = [
    ...
    'rest_framework',
    'snippets',
]

add

REST_FRAMEWORK = {
    'DEFAULT_PAGINATION_CLASS': 'rest_framework.pagination.PageNumberPagination',
    'PAGE_SIZE': 10
}

python manage.py makemigrations snippets
python manage.py migrate snippets

snippets/model.py

from django.db import models
from pygments.lexers import get_all_lexers
from pygments.styles import get_all_styles
from pygments.lexers import get_lexer_by_name
from pygments.formatters.html import HtmlFormatter
from pygments import highlight

LEXERS = [item for item in get_all_lexers() if item[1]]
LANGUAGE_CHOICES = sorted([(item[1][0], item[0]) for item in LEXERS])
STYLE_CHOICES = sorted([(item, item) for item in get_all_styles()])


class Snippet(models.Model):
    created = models.DateTimeField(auto_now_add=True)
    title = models.CharField(max_length=100, blank=True, default='')
    code = models.TextField()
    linenos = models.BooleanField(default=False)
    language = models.CharField(choices=LANGUAGE_CHOICES, default='python', max_length=100)
    style = models.CharField(choices=STYLE_CHOICES, default='friendly', max_length=100)
    owner = models.ForeignKey('auth.User', related_name='snippets', on_delete=models.CASCADE)
    highlighted = models.TextField()
    class Meta:
        ordering = ['created']
        
    def save(self, *args, **kwargs):
        """
        Use the `pygments` library to create a highlighted HTML
        representation of the code snippet.
        """
        lexer = get_lexer_by_name(self.language)
        linenos = 'table' if self.linenos else False
        options = {'title': self.title} if self.title else {}
        formatter = HtmlFormatter(style=self.style, linenos=linenos,
                                full=True, **options)
        self.highlighted = highlight(self.code, lexer, formatter)
        super().save(*args, **kwargs)

snippets/urls.py

from django.urls import path
from rest_framework.urlpatterns import format_suffix_patterns
from snippets import views

# API endpoints
urlpatterns = format_suffix_patterns([
    path('', views.api_root),
    path('snippets/',
        views.SnippetList.as_view(),
        name='snippet-list'),
    path('snippets/<int:pk>/',
        views.SnippetDetail.as_view(),
        name='snippet-detail'),
    path('snippets/<int:pk>/highlight/',
        views.SnippetHighlight.as_view(),
        name='snippet-highlight'),
    path('users/',
        views.UserList.as_view(),
        name='user-list'),
    path('users/<int:pk>/',
        views.UserDetail.as_view(),
        name='user-detail')
])

tut2/urls.py


from django.contrib import admin
from django.urls import path, include

urlpatterns = [
    path('admin/', admin.site.urls),
    path('', include('snippets.urls')),
]

urlpatterns += [
    path('api-auth/', include('rest_framework.urls')),
]

snippets/views.py

from snippets.models import Snippet
from snippets.serializers import SnippetSerializer
from rest_framework import generics
from rest_framework import permissions
from snippets.permissions import IsOwnerOrReadOnly

class SnippetList(generics.ListCreateAPIView):
    permission_classes = [permissions.IsAuthenticatedOrReadOnly,
                      IsOwnerOrReadOnly]
    queryset = Snippet.objects.all()
    serializer_class = SnippetSerializer
    def perform_create(self, serializer):
        serializer.save(owner=self.request.user)

class SnippetDetail(generics.RetrieveUpdateDestroyAPIView):
    permission_classes = [permissions.IsAuthenticatedOrReadOnly,
                      IsOwnerOrReadOnly]
    queryset = Snippet.objects.all()
    serializer_class = SnippetSerializer
    
    
from django.contrib.auth.models import User
from snippets.serializers import UserSerializer

class UserList(generics.ListAPIView):
    queryset = User.objects.all()
    serializer_class = UserSerializer


class UserDetail(generics.RetrieveAPIView):
    queryset = User.objects.all()
    serializer_class = UserSerializer
    
    
from rest_framework.decorators import api_view
from rest_framework.response import Response
from rest_framework.reverse import reverse


@api_view(['GET'])
def api_root(request, format=None):
    return Response({
        'users': reverse('user-list', request=request, format=format),
        'snippets': reverse('snippet-list', request=request, format=format)
    })
    
from rest_framework import renderers

class SnippetHighlight(generics.GenericAPIView):
    queryset = Snippet.objects.all()
    renderer_classes = [renderers.StaticHTMLRenderer]

    def get(self, request, *args, **kwargs):
        snippet = self.get_object()
        return Response(snippet.highlighted)

snippets/serializers.py

from rest_framework import serializers
from snippets.models import Snippet, LANGUAGE_CHOICES, STYLE_CHOICES
from django.contrib.auth.models import User


class SnippetSerializer(serializers.HyperlinkedModelSerializer):
    owner = serializers.ReadOnlyField(source='owner.username')
    highlight = serializers.HyperlinkedIdentityField(view_name='snippet-highlight', format='html')

    class Meta:
        model = Snippet
        fields = ['url', 'id', 'highlight', 'owner',
                  'title', 'code', 'linenos', 'language', 'style']


class UserSerializer(serializers.HyperlinkedModelSerializer):
    snippets = serializers.HyperlinkedRelatedField(many=True, view_name='snippet-detail', read_only=True)

    class Meta:
        model = User
        fields = ['url', 'id', 'username', 'snippets']

snippets/permissions.pyt

from rest_framework import permissions


class IsOwnerOrReadOnly(permissions.BasePermission):
    """
    Custom permission to only allow owners of an object to edit it.
    """

    def has_object_permission(self, request, view, obj):
        # Read permissions are allowed to any request,
        # so we'll always allow GET, HEAD or OPTIONS requests.
        if request.method in permissions.SAFE_METHODS:
            return True

        # Write permissions are only allowed to the owner of the snippet.
        return obj.owner == request.user
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