Question

我在Windows 10 Pro x64上的Python 3.6中实现基本HTTPServer时遇到问题。

基本上，socketserver.serve_forever()的基本实现中使用的选择器使用选择器来确定套接字是否可读。问题在于服务器收到单个GET请求后，它始终评估为true。因此，让我们以接收单个GET请求的情况为例。处理了GET，刷新了套接字，但是selector.select仍返回true，因此服务器尝试读取空套接字，导致其挂起并阻塞。

socketserver.serveforever：

def serve_forever(self, poll_interval=0.5):
        """Handle one request at a time until shutdown.

        Polls for shutdown every poll_interval seconds. Ignores
        self.timeout. If you need to do periodic tasks, do them in
        another thread.
        """
        self.__is_shut_down.clear()
        try:
            # XXX: Consider using another file descriptor or connecting to the
            # socket to wake this up instead of polling. Polling reduces our
            # responsiveness to a shutdown request and wastes cpu at all other
            # times.
            with _ServerSelector() as selector:
                selector.register(self, selectors.EVENT_READ)  
                while not self.__shutdown_request:
                    ready = selector.select(poll_interval)
                    if ready:
                        self._handle_request_noblock()

                    self.service_actions()
        finally:
            self.__shutdown_request = False
            self.__is_shut_down.set()

选择器。选择：

    if sys.platform == 'win32':
        def _select(self, r, w, _, timeout=None):
            r, w, x = select.select(r, w, w, timeout)
            return r, w + x, []
    else:
        _select = select.select

    def select(self, timeout=None):
        timeout = None if timeout is None else max(timeout, 0)
        ready = []
        try:
            r, w, _ = self._select(self._readers, self._writers, [], timeout)
        except InterruptedError:
            return ready
        r = set(r)
        w = set(w)
        for fd in r | w:
            events = 0
            if fd in r:
                events |= EVENT_READ
            if fd in w:
                events |= EVENT_WRITE

            key = self._key_from_fd(fd)
            if key:
                ready.append((key, events & key.events))
        return ready

这似乎是selector中的这一行。一旦收到GET请求，它将永久返回r的值：

r, w, x = select.select(r, w, w, timeout)。

** EDIT1失败的基本实现

MyServer.py

import http
from http import server

class Server(server.HTTPServer):
    pass

MyRequestHandler.py

from http.server import BaseHTTPRequestHandler
import urllib

class OAuthGrantRequestHandler(BaseHTTPRequestHandler):
    """docstring"""

    def do_GET(self):
        self.send_response(200)
        self.send_header('Content-type', 'text/html')
        self.end_headers()
        parts = urllib.parse.urlparse(self.path)
        self.wfile.write(
            b'<html><head><title>Authentication Status</title></head>'
            b'<body><p>The authentication flow has completed.</p>')

        print("Request handler completed")
        return

MyTest.py

import MyServer
import MyRequestHandler
import threading

def AwaitCallback(server_class=MyServer.Server,
                    handler_class=MyRequestHandler.OAuthGrantRequestHandler):
    """docstring"""

    server_address = ("127.0.0.1", 8080)
    Httpd = server_class(server_address, handler_class)
    Httpd.timeout = 200
    t1 = threading.Thread(target=Httpd.serve_forever, args=(1,))

    try:
        t1.start()

    finally:

        if t1:
            t1.join()
        print("thread 3 terminated")
        if Httpd:
            Httpd.server_close()

    return 

AwaitCallback()

运行测试后，我只是将localhost：8080放到我最喜欢的浏览器和wallah中，服务器成功响应然后锁定。

Answer 1

在选择器上。选择改变

def _select(self, r, w, _, timeout=None):

进入

def _select(self, r, w, x, timeout=None):

Python选择器。选择以可读方式返回空套接字

1 个答案: