检索套接字中的空文本

如何解决检索套接字中的空文本

我正在将数据从客户端发送到服务器。我正在从客户端检索数据，并将其存储在变量中并调用一个函数，但是当我运行程序时，在输出中得到空值。 收到以下输出

 Received b'' 

我也希望将字符串与字符串一起打印。谢谢 导入套接字

HOST = '127.0.0.1'  # Standard loopback interface address (localhost)
PORT = 65432        # Port to listen on (non-privileged ports are > 1023)


def ceaser(data):
 shift = 3  # defining the shift count

 encrypted_text = data
 plain_text = ""
 for c in encrypted_text:

    # check if character is an uppercase letter
    if c.isupper():
        # find the position in 0-25
        c_unicode = ord(c)
        c_index = ord(c) - ord("A")
        # perform the negative shift
        new_index = (c_index - shift) % 26
        # convert to new character
        new_unicode = new_index + ord("A")
        new_character = chr(new_unicode)
        # append to plain string
        plain_text = plain_text + new_character
        return plain_text
    else:

        # since character is not uppercase,leave it as it is
        plain_text += c
    return plain_text

with socket.socket(socket.AF_INET,socket.SOCK_STREAM) as s:
  s.bind((HOST,PORT))
  s.listen()
  conn,addr = s.accept()
  with conn:
    print('Connected by',addr)
    while True:
        data = conn.recv(1024)
        data=ceaser(data)
        if not data:
            break
        conn.sendall(data)

＃客户端

 with socket.socket(socket.AF_INET,socket.SOCK_STREAM) as s:
   s.connect((HOST,PORT))
   s.sendall(b'KHOOR ZRUOG')
   data = s.recv(1024)
   print('Received',repr(data))

解决方法

尽管要找出造成这种麻烦的直接原因，但我还是建议开发一种协议来使用，甚至只是一个基本协议。我的意思是首先发送有关即将到来的消息的信息，例如它包含的字节数。通过使用空字节填充此信息，可以将其保留在固定长度的数据包中。这样，您首先读取了一个大小为512的数据包。然后，您对该数据进行了解码并知道了该消息的大小，并可以调整public ActionResult Index() { var data = db.jobs. AsEnumerable(). OrderByDescending(x => x.JobDateTime). Select(a => new JobViewModel { MassDateTime = a.JobDateTime.ToString("dddd,dd MMMM yyyy hh:mm") }).ToList(); return View(data); } 来接受该字节数。

要记住的另一件事是消息的编码。处理消息时使用str是个好习惯，但是在发送和接收消息时，请使用.decode（）和.encode（）将其转换为字节。

,

下面是正确的代码。现在可以正常工作。

服务器

import socket
HOST = '127.0.0.1'  # Standard loopback interface address (localhost)
PORT = 65432        # Port to listen on (non-privileged ports are > 1023)


def ceaser(data):
    shift = 3  # defining the shift count

    encrypted_text = data.decode('utf-8')
    plain_text = ""
    for c in encrypted_text:
        # check if character is an uppercase letter
        if c.isupper():
            # find the position in 0-25
            c_unicode = ord(c)
            c_index = ord(c) - ord("A")
            # perform the negative shift
            new_index = (c_index - shift) % 26
            # convert to new character
            new_unicode = new_index + ord("A")
            new_character = chr(new_unicode)
            # append to plain string
            plain_text = plain_text + new_character
            #return plain_text
        else:
            # since character is not uppercase,leave it as it is
            plain_text += c
    return plain_text

with socket.socket(socket.AF_INET,socket.SOCK_STREAM) as s:
    s.bind((HOST,PORT))
    s.listen()
    conn,addr = s.accept()
    with conn:
        print('Connected by',addr)
        while True:
            data = conn.recv(1024)
            data=ceaser(data)
            if not data:
                break
            conn.sendall(data.encode('utf-8'))

客户

import socket
HOST = '127.0.0.1' 
PORT = 65432
with socket.socket(socket.AF_INET,socket.SOCK_STREAM) as s:
   s.connect((HOST,PORT))
   s.sendall(b'KHOOR ZRUOG')
   data = s.recv(1024)
   print('Received',repr(data))

出了什么问题？

• 您必须先解密接收到的内容，然后再解密，然后再发送。在服务器的第6行和最后一行。
• 您需要在caeser函数的for循环之外使用return语句