To create a Django API endpoint for registering a user and generating a JSON Web Token (JWT) using function-based views, you can follow these steps:

1. Install the required packages:

   pip install django djangorestframework djangorestframework-simplejwt

2. Create a Django project and app
   

   django-admin startproject myproject
   cd myproject
   python manage.py startapp myapp
   ​

3. Configure Django settings in settings.py:

   INSTALLED_APPS = [
       ...
       'rest_framework',
       'myapp',
   ]
   
   REST_FRAMEWORK = {
       'DEFAULT_AUTHENTICATION_CLASSES': [
           'rest_framework_simplejwt.authentication.JWTAuthentication',
       ],
   }
   
   SIMPLE_JWT = {
       'AUTH_HEADER_TYPES': ('JWT',),
   }
   

    

4. Define the user registration and authentication endpoints in myapp/views.py:

   from rest_framework.decorators import api_view
   from rest_framework.response import Response
   from rest_framework import status
   from django.contrib.auth.models import User
   from rest_framework_simplejwt.tokens import RefreshToken
   
   @api_view(['POST'])
   def register_user(request):
       username = request.data.get('username')
       password = request.data.get('password')
   
       if not username or not password:
           return Response({'error': 'Please provide both username and password.'}, status=status.HTTP_400_BAD_REQUEST)
   
       try:
           user = User.objects.create_user(username=username, password=password)
           refresh = RefreshToken.for_user(user)
           return Response({'token': str(refresh.access_token)}, status=status.HTTP_201_CREATED)
       except:
           return Response({'error': 'Unable to register the user.'}, status=status.HTTP_500_INTERNAL_SERVER_ERROR)
   
   @api_view(['POST'])
   def authenticate_user(request):
       username = request.data.get('username')
       password = request.data.get('password')
   
       if not username or not password:
           return Response({'error': 'Please provide both username and password.'}, status=status.HTTP_400_BAD_REQUEST)
   
       try:
           user = User.objects.get(username=username)
           if user.check_password(password):
               refresh = RefreshToken.for_user(user)
               return Response({'token': str(refresh.access_token)}, status=status.HTTP_200_OK)
           else:
               return Response({'error': 'Invalid credentials.'}, status=status.HTTP_401_UNAUTHORIZED)
       except User.DoesNotExist:
           return Response({'error': 'Invalid credentials.'}, status=status.HTTP_401_UNAUTHORIZED)
   

   5. Define the API endpoints in myapp/urls.py:

   from django.urls import path
   from myapp import views
   
   urlpatterns = [
       path('register/', views.register_user, name='register_user'),
       path('authenticate/', views.authenticate_user, name='authenticate_user'),
   ]
   

   6.  Include the app URLs in the project urls.py:

   from django.urls import path, include
   
   urlpatterns = [
       ...
       path('api/', include('myapp.urls')),
   ]
   

    7.  Run the development server:

    

   python manage.py runserver
   ​

   Now you should be able to send POST requests to the following endpoints:

   • To register a user: http://localhost:8000/api/register/

     • Request body: {"username": "myusername", "password": "mypassword"}
     • Response: {"token": "your-jwt-token"}

   • To authenticate a user: http://localhost:8000/api/authenticate/

     • Request body: {"username": "myusername", "password": "mypassword"}
     • Response: {"token": "your-jwt-token"}

   Remember to replace localhost:8000 with the appropriate URL if you are running the server on a different host or port.