为什么chrome总是创建三个连接，而只使用其中的两个

Question

Chrome版本70.0.3538.102

以下是我的简单http服务器(在python中(的代码

from socket import *
import sys
server_socket = socket(AF_INET, SOCK_STREAM)
server_socket.bind(('localhost', 8080))
server_socket.listen(5)
print('Starting up http-server, serving ./')
print('Available on:')
print('  http://localhost:8080')
print('Hit CTRL-BREAK to stop the server')
while True:
    connection_socket, address = server_socket.accept()
    print()
    print('Connected by: ', address[0] + ':' + str(address[1]))
    try:
        message = connection_socket.recv(1024)
        filename = message.split()[1]
        print('Filename to get: ', filename[1:].decode())
        f = open(filename[1:], 'rb')
        output_data = f.read()
        connection_socket.send('HTTP/1.1 200 OKrnrn'.encode())
        connection_socket.send(output_data)
        connection_socket.send('rn'.encode())
        connection_socket.close()
    except IOError:
        connection_socket.send('HTTP/1.1 404 Not Foundrnrn'.encode())
        connection_socket.send('404 Not Found'.encode())
        connection_socket.send('rn'.encode())
        connection_socket.close()
server_socket.close()
sys.exit()

我用Microsoft Edge测试了它，它的输出如下：

Starting up http-server, serving ./
Available on:
  http://localhost:8080
Hit CTRL-BREAK to stop the server
Connected by:  127.0.0.1:60998
Filename to get:  test.html

但当我把浏览器切换到Chrome浏览器后，发生了一件非常奇怪的事情。

Starting up http-server, serving ./
Available on:
  http://localhost:8080
Hit CTRL-BREAK to stop the server
Connected by:  127.0.0.1:61332
Filename to get:  test.html
Connected by:  127.0.0.1:61333
Filename to get:  favicon.ico
Connected by:  127.0.0.1:61335
Traceback (most recent call last):
  File "http-server.py", line 20, in <module>
    filename = message.split()[1]
IndexError: list index out of range

Chrome似乎打开了三个连接，但只使用了其中的两个。上次连接没有向服务器发送任何消息。

Answer 1

您可以使用except IndexError:修复此错误
修复代码如下：

from socket import *
import sys
server_socket = socket(AF_INET, SOCK_STREAM)
server_socket.bind(('localhost', 8080))
server_socket.listen(5)
print('Starting up http-server, serving ./')
print('Available on:')
print('  http://localhost:8080')
print('Hit CTRL-BREAK to stop the server')
while True:
    connection_socket, address = server_socket.accept()
    print()
    print('Connected by: ', address[0] + ':' + str(address[1]))
    try:
        message = connection_socket.recv(1024)
        filename = message.split()[1]
        print('Filename to get: ', filename[1:].decode())
        f = open(filename[1:], 'rb')
        output_data = f.read()
        connection_socket.send('HTTP/1.1 200 OKrnrn'.encode())
        connection_socket.send(output_data)
        connection_socket.send('rn'.encode())
        connection_socket.close()
    except IOError:
        connection_socket.send('HTTP/1.1 404 Not Foundrnrn'.encode())
        connection_socket.send('404 Not Found'.encode())
        connection_socket.send('rn'.encode())
        connection_socket.close()
    except IndexError:
        # what you want to do when request is invalid
server_socket.close()
sys.exit()