Raspberry Pi网络服务器对局域网上的iOS设备响应缓慢。

Question

我有一个Raspberry Pi，运行最新的Raspbian，执行一个简单的Python Web服务器。下面是这部分的代码。

# This is the main class for the web server
class MyHandler(BaseHTTPRequestHandler):
    # These are the headers that are sent as a response to every request
    def _set_headers(self):
        self.send_response(200)
        self.send_header('Content-type', 'text/html')
        self.end_headers()

    # This is the new POST method to get around background refresh problems
    def do_POST(self):
        # Get the content of the POST request
        content_length = int(self.headers['Content-Length'])
        post_data = self.rfile.read(content_length)

        # Split the text on the = of the key value pair, and keep the text of the operation.
        operationRequested = post_data.split("=")[1];
        logging.info(self.client_address[0] + " has requested operation " + operationRequested)

        # Handle each type of request. It's limited by the HTML file.
        if operationRequested == "openLeftDoor":
            leftDoor.openDoor()
        if operationRequested == "closeLeftDoor":
            leftDoor.closeDoor()
        if operationRequested == "openRightDoor":
            rightDoor.openDoor()
        if operationRequested == "closeRightDoor":
            rightDoor.closeDoor()

        self._set_headers()
        self.wfile.write(operationRequested + " completed.")

    # This is how we handle a GET request. We sense the URL within this method
    def do_GET(self):

        logging.info(self.client_address[0] + " has requested page " + self.path)

        # Handle the GET for the log file.
        if self.path == '/getlogs':
            try:
                htmlPage = open(logFilename)
                self.send_response(200)
                self.send_header('Content-type', 'text/html')
                self.end_headers()

                # Change carriage returns to HTML line breaks
                logFile = htmlPage.read()
                logFile = logFile.replace('\n', '<br>')

                self.wfile.write(logFile)
                self.wfile.write(htmlPage.read())
                htmlPage.close()
                return
            except IOError:
                logging.info("An IO Error happened during get logs!")

        # Handle the root request for the welcome page. This can't be an else as that disallows favicon requests.
        if self.path == "/":
            try:
                htmlPage = open("WelcomePage.html")
                self.send_response(200)
                self.send_header('Content-type', 'text/html')
                self.end_headers()
                self.wfile.write(htmlPage.read())
                htmlPage.close()
                return
            except IOError as e:
                logging.info("An IO Error happened during get welcome page!")
                logging.info(repr(e))

# This is the entry point to the webserver. The try catch looks after closing the socket with Ctrl C.
try:
    myServer = SocketServer.TCPServer(("", 80), MyHandler)
    myServer.serve_forever()
except KeyboardInterrupt:
    logging.info(' received, shutting down the web server')
finally:
    myServer.server_close()
    logging.info("Server has been closed")
logging.info("Bye!")

只有在我的局域网内才能访问这个网站 有线和无线客户端都能访问。我在使用基于Windows 10的笔记本电脑时从来没有遇到过问题，但是在iOS上可能有50%的时间，初始页面的加载速度非常慢，可能需要30秒。代码没有抛出任何异常，我已经能够找到。

这种情况似乎在iOS上将页面添加到主屏幕与在Safari中添加书签时更为普遍。都是只用IP地址，根本没有DNS解析。

一旦iOS设备第一次加载了页面，后续对同一服务器的浏览都是即时的。

我已经验证了Pi的wifi没有设置为睡眠状态，这是一个RSSI SNR极好的区域。我已经在两部不同的iPhone上重现了它。

Answer 1

这是因为我在webserver中没有设置favicon.ico和它的衍生品造成的。

当在iPhone上打开页面时，特别是从主屏幕上打开，在后台设备会请求这些图标。web服务器并没有设置成处理同时请求的状态，所以在处理用户的请求和渲染页面之前，它都处于等待每次请求超时的状态。

我通过在do_GET方法中增加一个else case来解决这个问题，处理通配符URL，返回一个默认图标。