Django + React: How to handle CSRF tokens in API requests?
I'm working on a Django project and encountering an issue with Django forms. Here's my current implementation:
# models.py
from django.db import models
class UserProfile(models.Model):
user = models.OneToOneField(User, on_delete=models.CASCADE)
bio = models.TextField()
# Signal handler
@receiver(post_save, sender=User)
def create_profile(sender, instance, created, **kwargs):
if created:
UserProfile.objects.create(user=instance)
The specific error I'm getting is: "django.urls.exceptions.NoReverseMatch: Reverse for 'article_detail' not found"
I've already tried the following approaches:
- Checked Django documentation and Stack Overflow
- Verified my database schema and migrations
- Added debugging prints to trace the issue
- Tested with different data inputs
Environment details:
- Django version: 5.0.1
- Python version: 3.11.0
- Database: PostgreSQL 15
- Operating system: macOS Ventura
Has anyone encountered this before? Any guidance would be greatly appreciated!
5 Answers
To optimize Django QuerySets and avoid N+1 problems, use select_related() for ForeignKey and OneToOneField, and prefetch_related() for ManyToManyField and reverse ForeignKey:
# Bad: N+1 query problem
for book in Book.objects.all():
print(book.author.name) # Each iteration hits the database
# Good: Use select_related for ForeignKey
for book in Book.objects.select_related('author'):
print(book.author.name) # Single query with JOIN
# Good: Use prefetch_related for ManyToMany
for book in Book.objects.prefetch_related('categories'):
for category in book.categories.all():
print(category.name) # Optimized with separate query
You can also use only() to limit fields and defer() to exclude heavy fields:
# Only fetch specific fields
Book.objects.only('title', 'author__name').select_related('author')
# Defer heavy fields
Book.objects.defer('content', 'description')
The choice between Django signals and overriding save() depends on your use case:
Use save() method when:
- The logic is directly related to the model
- You need to modify the instance before saving
- The operation is essential for data integrity
class Article(models.Model):
title = models.CharField(max_length=200)
slug = models.SlugField(unique=True)
def save(self, *args, **kwargs):
if not self.slug:
self.slug = slugify(self.title)
super().save(*args, **kwargs)
Use signals when:
- You need decoupled logic
- Multiple models need the same behavior
- You're working with third-party models
from django.db.models.signals import post_save
from django.dispatch import receiver
@receiver(post_save, sender=User)
def create_user_profile(sender, instance, created, **kwargs):
if created:
UserProfile.objects.create(user=instance)
Comments
joseph: This Django transaction approach worked perfectly for my payment processing system. Thanks! 1 week, 4 days ago
The choice between Django signals and overriding save() depends on your use case:
Use save() method when:
- The logic is directly related to the model
- You need to modify the instance before saving
- The operation is essential for data integrity
class Article(models.Model):
title = models.CharField(max_length=200)
slug = models.SlugField(unique=True)
def save(self, *args, **kwargs):
if not self.slug:
self.slug = slugify(self.title)
super().save(*args, **kwargs)
Use signals when:
- You need decoupled logic
- Multiple models need the same behavior
- You're working with third-party models
from django.db.models.signals import post_save
from django.dispatch import receiver
@receiver(post_save, sender=User)
def create_user_profile(sender, instance, created, **kwargs):
if created:
UserProfile.objects.create(user=instance)
Comments
joseph: I'm getting a similar error but with PostgreSQL instead of SQLite. Any differences in the solution? 1 week, 4 days ago
Here's a comprehensive approach to implementing JWT authentication in Django REST Framework:
# settings.py
INSTALLED_APPS = [
'rest_framework',
'rest_framework_simplejwt',
]
REST_FRAMEWORK = {
'DEFAULT_AUTHENTICATION_CLASSES': (
'rest_framework_simplejwt.authentication.JWTAuthentication',
),
'DEFAULT_PERMISSION_CLASSES': [
'rest_framework.permissions.IsAuthenticated',
],
}
from datetime import timedelta
SIMPLE_JWT = {
'ACCESS_TOKEN_LIFETIME': timedelta(minutes=60),
'REFRESH_TOKEN_LIFETIME': timedelta(days=7),
'ROTATE_REFRESH_TOKENS': True,
}
# urls.py
from rest_framework_simplejwt.views import (
TokenObtainPairView,
TokenRefreshView,
)
urlpatterns = [
path('api/token/', TokenObtainPairView.as_view()),
path('api/token/refresh/', TokenRefreshView.as_view()),
]
# Custom serializer for additional user data
from rest_framework_simplejwt.serializers import TokenObtainPairSerializer
class CustomTokenObtainPairSerializer(TokenObtainPairSerializer):
@classmethod
def get_token(cls, user):
token = super().get_token(user)
token['username'] = user.username
token['email'] = user.email
return token
Comments
abdullah: I'm getting a similar error but with PostgreSQL instead of SQLite. Any differences in the solution? 1 week, 4 days ago
abaditaye: I'm getting a similar error but with PostgreSQL instead of SQLite. Any differences in the solution? 1 week, 4 days ago
The difference between threading and multiprocessing in Python is crucial for performance:
Threading (shared memory, GIL limitation):
import threading
import time
def io_bound_task(name):
print(f'Starting {name}')
time.sleep(2) # Simulates I/O operation
print(f'Finished {name}')
# Good for I/O-bound tasks
threads = []
for i in range(3):
t = threading.Thread(target=io_bound_task, args=(f'Task-{i}',))
threads.append(t)
t.start()
for t in threads:
t.join()
Multiprocessing (separate memory, no GIL):
import multiprocessing
import time
def cpu_bound_task(name):
# CPU-intensive calculation
result = sum(i * i for i in range(1000000))
return f'{name}: {result}'
# Good for CPU-bound tasks
if __name__ == '__main__':
with multiprocessing.Pool(processes=4) as pool:
tasks = [f'Process-{i}' for i in range(4)]
results = pool.map(cpu_bound_task, tasks)
print(results)
Concurrent.futures (unified interface):
from concurrent.futures import ThreadPoolExecutor, ProcessPoolExecutor
# For I/O-bound tasks
with ThreadPoolExecutor(max_workers=4) as executor:
futures = [executor.submit(io_bound_task, f'Task-{i}') for i in range(4)]
results = [future.result() for future in futures]
# For CPU-bound tasks
with ProcessPoolExecutor(max_workers=4) as executor:
futures = [executor.submit(cpu_bound_task, f'Process-{i}') for i in range(4)]
results = [future.result() for future in futures]
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