Djangoミドルウェア分析

SessionMiddleware

        SESSION_COOKIE_NAME  Cookie

    django_session   SESSION_COOKIE_NAME     session，
  request  session  (SessionStore)，  _auth_user_id,_auth_user_backend,_auth_user_hash 
  response   session        cookie  

  ：

class SessionMiddleware(MiddlewareMixin):
    def __init__(self, get_response=None):
        #   session，django       
        self.get_response = get_response
        engine = import_module(settings.SESSION_ENGINE)
        self.SessionStore = engine.SessionStore

    def process_request(self, request):
        session_key = request.COOKIES.get(settings.SESSION_COOKIE_NAME) # cookie   sessionkey
        request.session = self.SessionStore(session_key) #  sessionkey django_session   session

    def process_response(self, request, response):
        """
        If request.session was modified, or if the configuration is to save the
        session every time, save the changes and set a session cookie or delete
        the session cookie if the session has been emptied.
        """
        try:
            accessed = request.session.accessed
            modified = request.session.modified
            empty = request.session.is_empty()
        except AttributeError:
            pass
        else:
            # First check if we need to delete this cookie.
            # The session should be deleted only if the session is entirely empty
            #   cookie sessionid     session   ， cookie  session  
            if settings.SESSION_COOKIE_NAME in request.COOKIES and empty:
                response.delete_cookie(
                    settings.SESSION_COOKIE_NAME,
                    path=settings.SESSION_COOKIE_PATH,
                    domain=settings.SESSION_COOKIE_DOMAIN,
                )
            else:
                if accessed:
                    patch_vary_headers(response, ('Cookie',))
                #      session      session  ，  session  ，       cookie（    500  ）
                if (modified or settings.SESSION_SAVE_EVERY_REQUEST) and not empty:
                    if request.session.get_expire_at_browser_close():
                        max_age = None
                        expires = None
                    else:
                        max_age = request.session.get_expiry_age()
                        expires_time = time.time() + max_age
                        expires = http_date(expires_time)
                    # Save the session data and refresh the client cookie.
                    # Skip session save for 500 responses, refs #3881.
                    if response.status_code != 500:
                        try:
                            request.session.save()
                        except UpdateError:
                            raise SuspiciousOperation(
                                "The request's session was deleted before the "
                                "request completed. The user may have logged "
                                "out in a concurrent request, for example."
                            )
                        response.set_cookie(
                            settings.SESSION_COOKIE_NAME,
                            request.session.session_key, max_age=max_age,
                            expires=expires, domain=settings.SESSION_COOKIE_DOMAIN,
                            path=settings.SESSION_COOKIE_PATH,
                            secure=settings.SESSION_COOKIE_SECURE or None,
                            httponly=settings.SESSION_COOKIE_HTTPONLY or None,
                            samesite=settings.SESSION_COOKIE_SAMESITE,
                        )
        return response

 
AuthenticationMiddleware
比較的簡単で、requestリクエストに基づいてrequestのuserとcache userを設定し、不活性なロードオブジェクトを返します.
ソース:
この時点で受信されたrequestに_がある場合cached_userではrequestからログインオブジェクトを取得する操作はスキップされます

def get_user(request):
    if not hasattr(request, '_cached_user'):
        request._cached_user = auth.get_user(request)
    return request._cached_user

 

class AuthenticationMiddleware(MiddlewareMixin):
    def process_request(self, request):
        #     session middleware，    
        assert hasattr(request, 'session'), (
            "The Django authentication middleware requires session middleware "
            "to be installed. Edit your MIDDLEWARE%s setting to insert "
            "'django.contrib.sessions.middleware.SessionMiddleware' before "
            "'django.contrib.auth.middleware.AuthenticationMiddleware'."
        ) % ("_CLASSES" if settings.MIDDLEWARE is None else "")
        #request.user  request      
        request.user = SimpleLazyObject(lambda: get_user(request))