Django Google OAuth2回调报错：需添加哪个backend参数？

我正在开发集成RESTful API的Django项目，实现用户注册、登录及Google/Apple OAuth登录功能。当前Google OAuth2回调环节触发内部服务器错误，报错信息如下：

/accounts/google/login/callback/ Traceback (most recent call last):
File "/home/zaibe/Desktop/project2/env/lib/python3.10/site-packages/django/core/handlers/exception.py", line 55, in inner
response = get_response(request) File "/home/zaibe/Desktop/project2/env/lib/python3.10/site-packages/django/core/handlers/base.py", line 197, in _get_response
response = wrapped_callback(request, *callback_args, **callback_kwargs) TypeError: api_google_oauth2_callback() missing 1 required positional argument: 'backend' [17/Mar/2024 06:39:23] "GET /accounts/google/login/callback/?code=4%2F0AeaYSHADSCseU_Nkg2BMLc5P8UpfRRqCJUNRIAyHrcW_tX4uQDpPADdj5rTJRS8v6siZHw&scope=email+profile+openid+https%3A%2F%2Fwww.googleapis.com%2Fauth%2Fuserinfo.profile+https%3A%2F%2Fwww.googleapis.com%2Fauth%2Fuserinfo.email&authuser=0&prompt=consent HTTP/1.1" 500 65562

视图代码 #

from django.http import JsonResponse
from django.contrib.auth import authenticate, login
from django.views.decorators.csrf import csrf_exempt
from .forms import UserRegistrationForm
from .models import Profile
from django.shortcuts import redirect
from social_django.utils import psa
import json
from social_django.views import auth
from django.views.generic import RedirectView
from django.shortcuts import render


def default_callback(request):
    return render(request, 'default_callback.html')

@psa()
def api_google_oauth2_login(request):
    backend = 'social_core.backends.google.GoogleOAuth2'
    return redirect('social:begin', backend=backend)

@psa()
def api_google_oauth2_callback(request):
    backend = 'social_core.backends.google.GoogleOAuth2'
    return auth(request, backend=backend)


@csrf_exempt
def api_user_login(request):
    if request.method == 'POST':
        # Retrieve raw JSON data from the request body
        data = json.loads(request.body)

        # Extract username and password from the JSON data
        username = data.get('username')
        password = data.get('password')

        if username is None or password is None:
            return JsonResponse({'error': 'Missing credentials'}, status=400)

        user = authenticate(request, username=username, password=password)
        if user is not None:
            login(request, user)
            return JsonResponse({'message': 'Authenticated successfully'}, status=200)
        else:
            return JsonResponse({'error': 'Invalid login'}, status=401)
    else:
        return JsonResponse({'error': 'Invalid request method'}, status=405)

@csrf_exempt
def api_user_register(request):
    if request.method == 'POST':
        form = UserRegistrationForm(request.POST)
        if form.is_valid():
            new_user = form.save(commit=False)
            new_user.set_password(form.cleaned_data['password'])
            new_user.save()
            Profile.objects.create(user=new_user)
            return JsonResponse({'message': 'Registration successful'}, status=201)
        else:
            return JsonResponse({'error': form.errors}, status=400)
    else:
        return JsonResponse({'error': 'Invalid request method'}, status=405)

class UserRedirectView(RedirectView):
    """
    This view is needed by the dj-rest-auth-library in order to work the google login. It's a bug.
    """

    permanent = False

    def get_redirect_url(self):
        return "http://127.0.0.1:8000/accounts/google/login/callback/"  # Replace "redirect-url" with your actual redirect URL

URL配置代码 #

from django.urls import path, include
from . import views

urlpatterns = [
    path('login/', views.api_user_login, name='api_user_login'),
    path('register/', views.api_user_register, name='api_user_register'),
    path('auth/', include('social_django.urls', namespace='social')),  # Social authentication URLs

    # Add the following URLs for Google OAuth2 authentication
    path('google/login/', views.api_google_oauth2_login, name='api_google_oauth2_login'),
    path('google/login/callback/', views.api_google_oauth2_callback, name='api_google_oauth2_callback'),

    path('default-callback/', views.default_callback, name='default_callback'),  # Remove trailing slash

    # Removed <str:backend> from the callback URL since it's not needed in this case

    # Add the redirect view URL
    path("~redirect/", view=views.UserRedirectView.as_view(), name="redirect"),
]

解决方案 #

报错核心原因是api_google_oauth2_callback函数未接收backend参数，但auth视图函数需要该参数，同时@psa()装饰器未正确注入backend。按以下两种方式之一修正即可：

方式一：通过装饰器固定注入backend（推荐）

直接给@psa装饰器指定Google OAuth2的backend路径，同时让函数保留backend参数位（设默认值避免报错）：

@psa('social_core.backends.google.GoogleOAuth2')
def api_google_oauth2_callback(request, backend=None):
    return auth(request, backend=backend)

该方式下，装饰器会自动注入指定的backend，无需URL传递参数，适配你当前的URL配置。

方式二：恢复URL中的backend参数

如果遵循social_django的默认逻辑，可将回调URL改回带<str:backend>的形式：

path('google/login/callback/<str:backend>/', views.api_google_oauth2_callback, name='api_google_oauth2_callback'),

同时调整视图函数接收backend参数：

@psa()
def api_google_oauth2_callback(request, backend):
    return auth(request, backend=backend)

两种方式都能解决"missing 1 required positional argument: 'backend'"的错误，推荐第一种方式，因为你的场景是固定使用Google OAuth2，无需动态传入backend。

内容的提问来源于stack exchange，提问作者zaibe_.x