python-3.x - 按下 "Ctrl+C"时 python 回显服务器的 Unicode 错误

Question

我已经创建了 python 回显服务器。可以使用命令启动回显服务器

sudo python3.8 echo_server.py

客户端可以使用命令连接到它

telnet localhost 5000

我已经实现了一些命令，如时间、退出和网络(即，如果您在 telnet 客户端上键入“时间”命令，服务器将以系统时间响应。)

“网络”命令包含 3 个 while 循环(即 1 个循环用于选择网络类型，2 个循环用于选择静态\动态，3 个循环用于配置 wifi 设置的 ssid/密码)。现在在配置 ssid/pwd 时，我想按“Ctrl+c”返回到 telnet 客户端的主命令提示符(即我们可以输入时间、网络命令的地方)。但是我无法处理回显服务器上的“Ctrl+c”。在 telnet 客户端上按下“Ctrl+c”时出现异常

Exception in thread MyThread:
Traceback (most recent call last):
  File "/usr/lib/python3.8/threading.py", line 932, in _bootstrap_inner
    self.run()
  File "echo_server.py", line 47, in run
    tx_data = ""
  File "/usr/lib/python3.8/codecs.py", line 322, in decode
    (result, consumed) = self._buffer_decode(data, self.errors, final)
UnicodeDecodeError: 'utf-8' codec can't decode byte 0xff in position 0: invalid start byte
Main Terminating...

请找到我的 echo_server.py 文件

import socket
import os
import os.path
import subprocess
import time
from subprocess import Popen, PIPE, STDOUT
from threading import Thread
from time import sleep

class MyThread(Thread):
 def __init__(self, val):
        ''' Constructor. '''
        Thread.__init__(self)
        self.val = val

 class Filter:
        """Substitute \n with \r\n in stream output to terminal."""

        def __init__(self, file):
            self.file = file

        def write(self, data):
            self.file.write(data.replace("\n", "\r\n"))

 def run(self):

  while True:
    HOST = ''                 # Symbolic name meaning all available interfaces
    PORT = 5000              # Arbitrary non-privileged port
    s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    s.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
    try:
        s.bind((HOST, PORT))
        s.listen(5)
    except socket.error:
        time.sleep(5)
        continue
    conn, addr = s.accept()
    file = conn.makefile(mode="rw")
    filtered_file =MyThread.Filter(file)
    file.flush()
    filtered_file.write("Enter 'help' to list all valid commands\n")
    while True:
        file.write("Command> ")
        file.flush()
        data = file.readline()
        tx_data = ""
        if not data: break
        data = data.strip()
        if not data:
            continue
        elif data == 'time':
           f= os.popen('date')
           date=f.read().strip()
           tx_data = date + '\n'

        elif data == "network":

            while True:
                file.write("1. WiFi\n")
                file.flush()                
                file.write("2. Ethenet\n")
                file.flush()
                file.write("3. Exi\n")
                file.flush()
                file.write("Enter a choice:")
                file.flush()
                choice = file.readline()
                choice = choice.strip()
                if choice == "1":
                    while True:
                         file.write("1. DHCP\n")
                         file.flush()                
                         file.write("2. Static\n")
                         file.flush()
                         file.write("3. Exit\n")
                         file.flush()
                         file.write("Enter a choice:")
                         file.flush()
                         subchoice = file.readline()
                         subchoice = choice.strip()
                         if subchoice == "1":
                             while True:
                                 file.write("Enter ssid:")
                                 file.flush()
                                 ssid = file.readline()
                                 ssid = ssid.strip()
                                 file.write("Enter pwd:")
                                 file.flush()
                                 pwd = file.readline()
                                 pwd = pwd.strip()
                                 break
                         break
                elif choice == "2":
                    break
                elif choice == "3":
                     break
                else:
                     break

        elif data == 'help':
            tx_data = '''Valid commands are as below:
Enter number against the command for execution

        1. time
        2. network
        3. exit\n'''

        elif data == 'exit':
            break

        else:
            tx_data = "Unknown Command: " + data + \
                    "\nEnter 'help' for list of valid commands\n"

        filtered_file.write(tx_data)
    #print 'Closing connection with client'
    file.close()
    conn.close()


# Run following code when the program starts
if __name__ == '__main__':
   # Declare objects of My Thread class
   my_obj = MyThread(4)
   my_obj.setName('MyThread')


   # Start running the threads!
   my_obj.start()

   # Wait for the threads to finish...
   my_obj.join()

   print('Main Terminating...')

我不确定如何处理“Ctrl+c”，以便在我们可以输入命令时控制回到提示符处。如果有人有任何解决此问题的建议，请告诉我。

Answer 1

这是我的程序版本:

# echo_server.py
import socket
import os
import os.path
import subprocess
import time
from subprocess import Popen, PIPE, STDOUT
from threading import Thread
from time import sleep

def getcommand(thisfile, thisprompt, stripped=True):
    thisfile.write(thisprompt)
    thisfile.flush()
    command = thisfile.readline()[:-1]
    # print(f"{len(command)} chars received")  # just for debug
    # for i in command:
    #    print(ord(i))
    if stripped:
        return command.strip()
    return command


class MyThread(Thread):
  def __init__(self, val):
        ''' Constructor. '''
        Thread.__init__(self)
        self.val = val

  class Filter:
        """Substitute \n with \r\n in stream output to terminal."""

        def __init__(self, file):
            self.file = file

        def write(self, data):
            self.file.write(data.replace("\n", "\r\n"))

  def run(self):

   while True:
      HOST = ''                 # Symbolic name meaning all available interfaces
      PORT = 5000              # Arbitrary non-privileged port
      s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
      s.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
      try:
        s.bind((HOST, PORT))
        s.listen(5)
      except socket.error:
        time.sleep(5)
        continue
      conn, addr = s.accept()
      file = conn.makefile(mode="rw", encoding="UTF-8", errors="ignore")
      filtered_file = MyThread.Filter(file)
      file.flush()
      filtered_file.write("Enter 'help' to list all valid commands\n")
      while True:
        data = getcommand(file, "Command> ", stripped=False)
        tx_data = ""
        if not data:
            print("No Command!")
            break  # closing connection
        data = data.strip()
        if not data:
            print("Just Spaces!")
            continue

        elif data == 'time':
           f= os.popen('date')
           date=f.read().strip()
           tx_data = date + '\n'

        elif data == "network":
            while True:
                file.write("1. WiFi\n")
                file.flush()                
                file.write("2. Ethernet\n")
                file.flush()
                file.write("3. Exit\n")
                file.flush()
                choice = getcommand(file, "Enter a choice:")
                if choice == "1":
                    while True:
                         file.write("1. DHCP\n")
                         file.flush()                
                         file.write("2. Static\n")
                         file.flush()
                         file.write("3. Exit\n")
                         file.flush()
                         subchoice = getcommand(file, "Enter a choice:")
                         if subchoice == "1":
                             while True:
                                 ssid = getcommand(file, "Enter ssid:")
                                 pwd = getcommand(file, "Enter password:")
                                 if ssid and pwd:
                                     break
                         break
                elif choice == "2":
                    break
                elif choice == "3":
                     break

        elif data == 'help':
            tx_data = '''Valid commands are as below:
Enter number against the command for execution

        1. time
        2. network
        3. exit\n'''

        elif data == 'exit':
            break

        else:
            tx_data = "Unknown Command: " + data + \
                    "\nEnter 'help' for list of valid commands\n"

        filtered_file.write(tx_data)
      print('Closing connection with client')
      file.close()
      conn.close()


# Run following code when the program starts
if __name__ == '__main__':
   # Declare objects of My Thread class
   my_obj = MyThread(4)
   my_obj.setName('MyThread')


   # Start running the threads!
   my_obj.start()

   # Wait for the threads to finish...
   my_obj.join()

   print('Main Terminating...')

我创建了一个新函数来处理来自终端的文本输入。此函数去除由 readline() 附加的新行字符，并可选择去除输入字符串中的前导和尾随空白。这使您可以选择在用户未输入任何数据时关闭连接，而在他/她只是输入空格时保持连接打开并重复提示。我还在 conn.makefile() 中使用了 'errors' 可选参数，以避免 UnicodeDecodeError，并添加了一行以重复输入 ssid 和密码(如果其中任何一个为空)。当主要选择是“网络”时，我还删除了 else 子句，让用户只能通过选择 3 来退出。使用此版本，无需使用 Ctrl-C(也有键盘中断的含义)，如果用户输入它，它不会再中断服务器。现在，如果您在客户端中按 Ctrl-C，您将停止接收服务器的输出，但如果您盲目地输入“退出”选项，您可以优雅地退出连接。