Question

我在项目中使用django-revproxy和Django REST Framework。我公开了一个API，用户可以在其中获取有关其聊天机器人的分析，其工作原理如下：

用户发送的请求来自Django项目的分析
Django项目，检查用户是否已通过身份验证并拥有该聊天机器人
if True它与另一个外部服务联系。

我的 urls.py ：

# urls.py
urlpatterns = (
    url(r'^analytics/(?P<path>.*)$', api.AnalyticsFunctionsProxyView.as_view()),
)

在我看来：

# views.py
from rest_framework.authentication import TokenAuthentication
from rest_framework_jwt.authentication import JSONWebTokenAuthentication
from rest_framework.permissions import IsAuthenticated
from revproxy.views import ProxyView
from .permissions import HasChatBotPermission

...

class AnalyticsFunctionsProxyView(ProxyView):
    upstream = settings.ANALYTICS_FAAS_URL

    def parse_body(self, request):
        if isinstance(request, rest_framework.request.Request):
            return request.data
        return super(AnalyticsFunctionsProxyView, self).parse_body(request)

    @classmethod
    def as_view(cls, *args, **kwargs):
        view = super(AnalyticsFunctionsProxyView, cls).as_view(*args, **kwargs)
        view = permission_classes((IsAuthenticated, HasChatBotPermission,))(view)
        view = authentication_classes([TokenAuthentication, JSONWebTokenAuthentication])(view)
        view = api_view(['GET', 'POST'])(view)


 return view

我的HasChatBotPermission权限

#permissions.py
class HasChatBotPermission(permissions.BasePermission):
    def has_permission(self, request, view):
        try:
            bot_name = request.data.get('name')
            user = request.user
            self.message = 'Permission denied for {}'.format(name)
            return ChatBot.objects.filter(user=user, project_name=project_id).exists()
        except Exception:
            self.message = 'Permission denied, no project_id was defined!'
            return False

调用视图时会引发以下异常：

Traceback (most recent call last):
  File "/home/fcmam5/dela3a/env/lib/python3.6/site-packages/rest_framework/request.py", line 379, in __getattribute__
    return super(Request, self).__getattribute__(attr)
AttributeError: 'Request' object has no attribute 'body'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/home/fcmam5/dela3a/env/lib/python3.6/site-packages/django/core/handlers/exception.py", line 42, in inner
    response = get_response(request)
  File "/home/fcmam5/dela3a/env/lib/python3.6/site-packages/django/core/handlers/base.py", line 187, in _get_response
    response = self.process_exception_by_middleware(e, request)
  File "/home/fcmam5/dela3a/env/lib/python3.6/site-packages/django/core/handlers/base.py", line 185, in _get_response
    response = wrapped_callback(request, *callback_args, **callback_kwargs)
  File "/home/fcmam5/anaconda3/lib/python3.6/contextlib.py", line 52, in inner
    return func(*args, **kwds)
  File "/home/fcmam5/dela3a/env/lib/python3.6/site-packages/django/views/decorators/csrf.py", line 58, in wrapped_view
    return view_func(*args, **kwargs)
  File "/home/fcmam5/dela3a/env/lib/python3.6/site-packages/django/views/generic/base.py", line 68, in view
    return self.dispatch(request, *args, **kwargs)
  File "/home/fcmam5/dela3a/env/lib/python3.6/site-packages/rest_framework/views.py", line 477, in dispatch
    response = self.handle_exception(exc)
  File "/home/fcmam5/dela3a/env/lib/python3.6/site-packages/rest_framework/views.py", line 437, in handle_exception
    self.raise_uncaught_exception(exc)
  File "/home/fcmam5/dela3a/env/lib/python3.6/site-packages/rest_framework/views.py", line 474, in dispatch
    response = handler(request, *args, **kwargs)
  File "/home/fcmam5/dela3a/env/lib/python3.6/site-packages/rest_framework/decorators.py", line 52, in handler
    return func(*args, **kwargs)
  File "/home/fcmam5/dela3a/env/lib/python3.6/site-packages/django/views/generic/base.py", line 68, in view
    return self.dispatch(request, *args, **kwargs)
  File "/home/fcmam5/dela3a/env/lib/python3.6/site-packages/revproxy/views.py", line 204, in dispatch
    proxy_response = self._created_proxy_response(request, path)
  File "/home/fcmam5/dela3a/env/lib/python3.6/site-packages/revproxy/views.py", line 139, in _created_proxy_response
    request_payload = request.body
  File "/home/fcmam5/dela3a/env/lib/python3.6/site-packages/rest_framework/request.py", line 383, in __getattribute__
    return getattr(self._request, attr)
  File "/home/fcmam5/dela3a/env/lib/python3.6/site-packages/django/http/request.py", line 264, in body
    raise RawPostDataException("You cannot access body after reading from request's data stream")
django.http.request.RawPostDataException: You cannot access body after reading from request's data stream

问题是由我的bot_name = request.data.get('name')中的这一行permissions.py引起的，当我直接传递字符串时，它顺利通过了。

我的问题是：

如何在不出现此错误的情况下访问请求正文？为什么我出现此错误？
是否有更好的解决方案，可以使用Django revproxy检查用户权限。

这是我在Stackoverflow中的第一个问题，对不起，如果我的问题不是英语，并且对我的英语不好：）

Answer 1

您遇到此错误是因为django-revproxy试图读取原始请求正文，以便它可以创建到上游服务器的代理请求。

但是，使用Django（以及WSGI和缓冲）语义，一旦您以但原始流的形式访问请求正文，就无法实现此目的，{{{ 1}}。根据DRF的请求协商配置，此操作会将请求正文解析为JSON，HTTP multipart等，并使用流。

据我所知，有两种解决方法：

将request.data.get('name')传递到身体以外的其他地方；例如查询字符串参数，HTTP标头，URL的一部分，因此您无需访问正文，或者
使用bot_name而不是反向代理来进行后端请求（这基本上是同一件事，但是增加了尝试按原样复制请求的功能）。

使用DRF和django-revproxy时出现“异常：从请求的数据流读取后无法访问正文”

1 个答案: