Couldnot resolve URL for hyperlinked relationship using view name "snippet-detail"or incorrectly configured the `lookup_field` attribute on this field

Question

ImproperlyConfigured at /snippet/5 Could not resolve URL for hyperlinked relationship using view name "snippet-detail". You may have failed to include the related model in your API, or incorrectly configured the lookup_field attribute on this field.

models.py

from email.policy import default
import imp
from tkinter import CASCADE
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
from django.contrib.auth.models import User
import snippets
# Create your models here.

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.CharField(max_length=250,default="0")
    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)

    class Meta:
        ordering=['created']

permissions.py

import imp
from rest_framework import permissions

class IsOwnerReadOnly(permissions.BasePermission):
    """custom permissions to only allow owners of an oject to edit

    """
    def has_object_permission(self, request, view, obj):
        if request.method in permissions.SAFE_METHODS:
            return True
        return obj.owner == request.user

serializers.py

from operator import mod

from numpy import source
from .models import *
from rest_framework import serializers
from snippets.models import Snippet, LANGUAGE_CHOICES,STYLE_CHOICES

class SnippetSerializer(serializers.HyperlinkedModelSerializer):
    owner = serializers.ReadOnlyField(source='owner.username')
    class Meta:
        model=Snippet
        fields = ['url', 'id',  'owner',
                  'created', 'title', 'linenos', 'language', 'style']
        # fields='__all__'
        # fields=['id','url','owner']



from django.contrib.auth.models import User


class UserSerializer(serializers.HyperlinkedModelSerializer):
    snippets=serializers.HyperlinkedRelatedField(lookup_field = 'username',many=True,view_name='snippet-details',read_only=True)
    owner=serializers.ReadOnlyField(source='owner.username')

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

views.py

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

class snippet_list(generics.ListCreateAPIView):
    queryset = Snippet.objects.all()
    serializer_class = SnippetSerializer

    def perform_create(self, serializer):
        serializer.save(owner=self.request.user)


class snippet_detail(generics.RetrieveUpdateDestroyAPIView):
    permission_classes=[permissions.IsAuthenticatedOrReadOnly,IsOwnerReadOnly]
    queryset = Snippet.objects.all()
    serializer_class = SnippetSerializer

    ##########################  authentication   purspose  #####################################################


from django.contrib.auth.models import User
from .serializers import *
from rest_framework import permissions

class UserList(generics.ListAPIView):
    permission_classes=[permissions.IsAuthenticatedOrReadOnly]
    queryset = User.objects.all()
    serializer_class = UserSerializer


class UserDetail(generics.RetrieveAPIView):
    permission_classes=[permissions.IsAuthenticatedOrReadOnly]
    queryset = User.objects.all()
    serializer_class = UserSerializer



#######################################  using hyperlinking for relationships   #################################################################

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)
    })

urls.py(api)

from rest_framework.urlpatterns import format_suffix_patterns
from django.urls import path,include
from snippets import views
from .views import *


urlpatterns=format_suffix_patterns([path('',views.api_root),
    path('snippet/',views.snippet_list.as_view(),name='snippet-list'),
    path('snippet/<int:pk>',views.snippet_detail.as_view(),name='snippet-details'),
    path('  ',views.UserList.as_view(),name='user-list'),
    path('Users/<int:pk>',views.UserDetail.as_view(),name='user-details'),
    
])

urls.py(main project)

from django.contrib import admin
# from snippets.urls import *
# from snippets.views import *
from django.urls import path, include

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

##########################  authentication   purspose  #####################################################


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

I'm new for django but learning and implementing and also sorting errors. But I got stuck with this error for 2 days. I done many changes but still not working.

Answer 1

It appears to me that you misspelled the url name in the urls.py You have

path('snippet/<int:pk>',views.snippet_detail.as_view(),name='snippet-details'),

replace it with

path('snippet/<int:pk>',views.snippet_detail.as_view(),name='snippet-detail')

remove the "s" from the name