python - 基本 HTTPServer 卡在 "socket.readinto : return self._sock.recv_into(b)"

Question

我有一个非常基本的 http.server.HTTPServer 实现，我正在 Python 3.6 中启动。我正在使用它根据 google Analytics API 对 OAuth2 进行身份验证。按照标准，我创建了一个简单的句柄来接收 OAuth2 授权 key ，并使用 serve_forever() 方法。然而，用于创建服务的线程永远挂了，它似乎在 Python 3.6 实现中卡得很深。

有趣的是，在这种情况下，我认为我的代码根本不重要。查看我为调试设置的监听器报告的调用堆栈:

service_action started
service_action complete
service_action started
service_action complete
service_action started
service_action complete
service_action started
service_action complete
"socketserver.BaseServer.serve_forever : self._handle_request_noblock()"
"socketserver.BaseServer._handle_request_noblock : self.get_request()"
"socketserver.BaseServer._handle_noblock_request : self.process_request()"
"socketserver.BaseServer.process_request : self.finish_request()"
"socketserver.BaseServer.finish_request : self.RequestHandlerClass(request, client_address, self) #  request == <socket.socket fd=1828, family=AddressFamily.AF_INET, type=SocketKind.SOCK_STREAM, proto=0, laddr=('127.0.0.1', 8080), raddr=('127.0.0.1', 57504)>,  client_address == ('127.0.0.1', 57504),  self == <MDGCoreLib.Utilities.HttpServer.Server.Server object at 0x0000026304E3FC88>"
"socketserver.BaseRequestHandler.__init__ : set self.client_address"
"socketserver.BaseRequestHandler.__init__ : set self.server"
"socketserver.BaseRequestHandler.__init__ : setup()"
"socketserver.StreamRequestHandler.setup : self.connection = self.request"
"socketserver.BaseRequestHandler.__init__ : self.handle()"
"server.BaseHttpRequestHandler.handle  : self.close_connection = True"
"server.BaseHTTPServer.handle_one_request : self.raw_requestline = self.rfile.readline(65537)"
"socket.readinto : self._checkClosed()"
"socket.readinto : return self._sock.recv_into(b)  #b == <memory at 0x0000026304E38C48>"
"server.BaseHTTPHandler.handle_one_request : if len(self.raw_requestline) > 65536"
"server.BaseHTTPHandler.handle_one_request : if not self.raw_requestline"
"server.BaseHTTPHandler.handle_one_request : if not self.parse_request()"
"server.BaseHTTPHandler.handle_one_request : if not hassattr(self, mname)"
#My handler runs
*"OAuthGrantRequestHandler : self.send_response"
127.0.0.1 - - [27/Aug/2018 14:35:16] "GET /?(REDACTED) HTTP/1.1" 200 -
Request handler completed*
#My handler finishes

Parent thread : joining Thread 2
"server.BaseHTTPHandler.handle_one_request : flushing wfile to socket finishing request"
"socketserver.BaseRequestHandler.__init__ : self.finish()"
"socketserver.StreamRequestHandler.finish : "
"socketserver.BaseServer.process_request : self.shutdown_request"
service_action started
service_action complete
"socketserver.BaseServer.serve_forever : self._handle_request_noblock()"
"socketserver.BaseServer._handle_request_noblock : self.get_request()"
"socketserver.BaseServer._handle_noblock_request : self.process_request()"
"socketserver.BaseServer.process_request : self.finish_request()"
"socketserver.BaseServer.finish_request : self.RequestHandlerClass(request, client_address, self) #  request == <socket.socket fd=1840, family=AddressFamily.AF_INET, type=SocketKind.SOCK_STREAM, proto=0, laddr=('127.0.0.1', 8080), raddr=('127.0.0.1', 57505)>,  client_address == ('127.0.0.1', 57505),  self == <MDGCoreLib.Utilities.HttpServer.Server.Server object at 0x0000026304E3FC88>"
"socketserver.BaseRequestHandler.__init__ : set self.client_address"
"socketserver.BaseRequestHandler.__init__ : set self.server"
"socketserver.BaseRequestHandler.__init__ : setup()"
"socketserver.StreamRequestHandler.setup : self.connection = self.request"
"socketserver.BaseRequestHandler.__init__ : self.handle()"
"server.BaseHttpRequestHandler.handle  : self.close_connection = True"
"server.BaseHTTPServer.handle_one_request : self.raw_requestline = self.rfile.readline(65537)"
"socket.readinto : self._checkClosed()"
"socket.readinto : return self._sock.recv_into(b)  #b == <memory at 0x0000026304E38C48>"
"server.BaseHTTPHandler.handle_one_request : if len(self.raw_requestline) > 65536"
"server.BaseHTTPHandler.handle_one_request : if not self.raw_requestline"
"server.BaseHTTPHandler.handle_one_request : if not self.parse_request()"
"server.BaseHTTPHandler.handle_one_request : if not hassattr(self, mname)"
#My Handler Runs
"OAuthGrantRequestHandler : self.send_response"
127.0.0.1 - - [27/Aug/2018 14:35:18] "GET /favicon.ico HTTP/1.1" 200 -
Request handler completed
#My Handler Finishes

"server.BaseHTTPHandler.handle_one_request : flushing wfile to socket finishing request"
"socketserver.BaseRequestHandler.__init__ : self.finish()"
"socketserver.StreamRequestHandler.finish : "
"socketserver.BaseServer.process_request : self.shutdown_request"
service_action started
service_action complete
"socketserver.BaseServer.serve_forever : self._handle_request_noblock()"
"socketserver.BaseServer._handle_request_noblock : self.get_request()"
"socketserver.BaseServer._handle_noblock_request : self.process_request()"
"socketserver.BaseServer.process_request : self.finish_request()"
"socketserver.BaseServer.finish_request : self.RequestHandlerClass(request, client_address, self) #  request == <socket.socket fd=2008, family=AddressFamily.AF_INET, type=SocketKind.SOCK_STREAM, proto=0, laddr=('127.0.0.1', 8080), raddr=('127.0.0.1', 57506)>,  client_address == ('127.0.0.1', 57506),  self == <MDGCoreLib.Utilities.HttpServer.Server.Server object at 0x0000026304E3FC88>"
"socketserver.BaseRequestHandler.__init__ : set self.client_address"
"socketserver.BaseRequestHandler.__init__ : set self.server"
"socketserver.BaseRequestHandler.__init__ : setup()"
"socketserver.StreamRequestHandler.setup : self.connection = self.request"
"socketserver.BaseRequestHandler.__init__ : self.handle()"
"server.BaseHttpRequestHandler.handle  : self.close_connection = True"
"server.BaseHTTPServer.handle_one_request : self.raw_requestline = self.rfile.readline(65537)"
"socket.readinto : self._checkClosed()"
"socket.readinto : return self._sock.recv_into(b)  #b == <memory at 0x0000026304E38C48>"
The program '[54321] Python @ tcp://localhost:55098/?legacyUnitTest' has exited with code -1 (0xffffffff).

以上是运行“serve_forever()”方法的线程的所有内容，您可以看到父线程正在等待加入，其中输出为 Parent thread : joining Thread 2。当输出为 "OAuthGrantRequestHandler : self.send_response" 和Request handler completed:但在内部 python 库卡在 socket.readinto : return self._sock.recv_into(b) 之前再也不会被调用，同时尝试处理最后一个要求。

以前有人遇到过这个 Python 挂断问题，它周围有什么问题吗？我有点不知所措，因为它卡在遇到我的处理程序/代码的 server_forever() 循环之间。

更新 1因此，将 fiddler 跟踪与 HTTPServer 中的请求进行比较，我发现只有两个 HTTPRequest，但是 HTTPServer.serve_forever() 尝试读取第三个请求，这是它挂起的地方。我还验证了(您可以在上面的输出中看到)正在调用“shutdown_request()”方法和底层方法来关闭套接字。那么为什么 serve_forever 循环继续通过下面的检查并在没有收到新请求时调用 self._handle_request_noblock() :

ready = selector.select(poll_interval)
                    if ready:
                        self._handle_request_noblock()

Answer 1

有几乎相同的问题，所以在深入了解 socketserver.StreamRequestHandler 实现后，我发现了如何设置超时，以便那些错误的读取尝试最终会解除阻塞。

    class MyRequestHandler(BaseHTTPRequestHandler):
        timeout = 2  # This is what makes the difference (seconds)

        def do_GET(self):
            ...