python - 错误的文件描述符socket.accept

Question

我正在处理的代码编译得很好，但是在 Web 服务器将消息发送到客户端之后，服务器退出并出现以下错误。另外，使用 serverAddr:serverPort/test.html 时，我的代码似乎永远不会到达 IOError block 。哪个应该返回“404页面未找到”通过查看回溯，我认为这可能只是我的机器设置的问题，但我不完全确定。难道是我的代码有问题吗？

#Tasks: Create a socket, bind to a specific address and port, send and receive an HTTP        packet.
#Description: Web server should handle one HTTP request at a time. So the serve closes its TCP connection after response.
#Accept and parse the HTTP request, get the requested file from the server (i.e.   HelloWorld.html), create a response
#message with the requested file and header lines, then send the response to the client.
#Error handling: If file not found then send HTTP "404 Not Found" Message back to client.

#import socket module: here we are using a low-level networking class from Python
from socket import * 

#create the socket that belongs to the server.
#AF_INTET represents the address families and protocols.
#SOCK_STREAM represents the socket type
serverSocket = socket(AF_INET, SOCK_STREAM) 

#Prepare a server socket 

#Define variable for serverPort; we'll use the one in the helper page of the book
serverPort = 51350
#Define host address
serverHost = ''

#Bind the socket to the local host machine address and port
serverSocket.bind((serverHost, serverPort))

#Listen for TCP connections from the client
serverSocket.listen(1)

#Verify setup for receiving
print 'Server is ready to receive'

while True: 
 #Establish the connection 
 print 'Ready to serve...' 
 #When the server receive a request from the client it must establish a new connectionSocket and begin taking in the data.
 connectionSocket, addr = serverSocket.accept()
 try: 
 #Take data from connectionSocket and place in message.
 #.recvfrom doesn't work because it expects data and return address variables.
    message = connectionSocket.recv(1024) 

    #uncomment for header information
    #print message

     #parse the message
    filename = message.split()[1] 
    f = open(filename[1:]) 
    outputdata = f.read();

 #Send one HTTP header line into socket 
    connectionSocket.send('HTTP/1.1 200 OK\r\n\r\n')

 #Send the content of the requested file to the client 
    for i in range(0, len(outputdata)): 
        connectionSocket.send(outputdata[i]) 

    connectionSocket.close() 

 except IOError:

 #Send response message for file not found 
    connectionSocket.send('404 Not Found')
    connectionSocket.close()

 #Close client socket 
 serverSocket.close() 


Traceback:
Server is ready to receive
Ready to serve...
Ready to serve...
Traceback (most recent call last):
  File "hw2.py", line 35, in <module>
    connectionSocket, addr = serverSocket.accept()
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/socket.py",      line 202, in accept
    sock, addr = self._sock.accept()
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/socket.py", line 170, in _dummy
    raise error(EBADF, 'Bad file descriptor')
socket.error: [Errno 9] Bad file descriptor

Answer 1

“准备服务...”打印了两次，因此在第一个连接工作后第二个连接上它就死掉了。发生这种情况是因为您在循环中关闭了服务器套接字。另外，您永远不会执行 f.close 来关闭您打开的文件。