socket粘包实例个人理解

 1 # server.py
 2 
 3 import socket
 4 import subprocess
 5 
 6 sk = socket.socket()
 7 
 8 sk.bind(('127.0.0.1', 8081))
 9 sk.listen(5)
10 
11 while True:
12     conn, addr = sk.accept()
13     while True:
14         try:
15 
16             recv_data = conn.recv(1024)
17             if len(recv_data) == 0:break
18             p = subprocess.Popen(str(recv_data, encoding='utf8'), shell=True, stdout=subprocess.PIPE)
19             res = p.stdout.read()
20             if len(res) == 0:
21                 send_data = 'cmd_err'
22 
23             else:
24                 send_data = str(res, encoding='gbk')
25 
26             send_data = bytes(send_data, encoding='utf8')
27 
28             ready_tag = 'Ready|%s' % len(send_data)
29 
30            # 这一步是关键，向客户端发送 消息和数据大小
31             conn.send(bytes(ready_tag, encoding='utf8'))
32 
33             feedback = conn.recv(1024)
34             # 收到客户端的消息
35             feedback = str(feedback, encoding='utf8')
36             # 开始发送数据
37             if feedback.startswith('Start'):
38                 conn.send(send_data)
39         except Exception:
40             break
41 
42     conn.close()
43 
44 
45 # client.py
46 
47 import socket
48 
49 cli = socket.socket()
50 
51 cli.connect(('127.0.0.1', 8081))
52 
53 while True:
54 
55     send_data = input('>>:').strip()
56     if send_data == 'exit':break
57     if len(send_data) == 0:continue
58     cli.send(bytes(send_data, encoding='utf-8'))
59     # 收到消息
60     ready_tag = cli.recv(1024)
61     ready_tag = str(ready_tag, encoding='utf-8')
62     if ready_tag.startswith('Ready'):
63         msg_size = int(ready_tag.split('|')[-1])
64 
65    # 告知服务端，我收到了消息
66     start_tag = 'Start'
67     cli.send(bytes(start_tag, encoding='utf8'))
68 
69     recv_size = 0
70     recv_msg = b''
71 
72     while recv_size<msg_size:
73         recv_data = cli.recv(1024)
74         recv_msg += recv_data
75         recv_size += len(recv_data)
76 
77         print('MSG SIZE %s RECE SIZE %s' % (msg_size, recv_size))
78     print(str(recv_msg, encoding='utf8'))
79 
80 
81 cli.close()    

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与原始的socke交互相比，个人理解就是在客户端向服务端发起请求，服务端在响应之前主动向客户端发送信号（| 数据的大小），多了一个交互的过程