利用Socket编写TCP客户端工具访问网站时接收数据的循环结束标志并不是None而是按照长度


　　代码比较简单，就是利用socket模块模拟TCP客户端，这里就是模拟浏览器发起对网站的访问，假设socket.recv(1024)所接收的内容长度大于1024字节，那么需要循环接收，那么结束的标志是什么呢？并不是None，而是按照接收到的数据长度来判断是否已经接收完整。

 1 import socket
 2 import sys
 3 import optparse
 4 
 5 class TCPClient:
 6     def __init__(self) -> None:
 7         self.target = self.get_params()[0]
 8         self.port = self.get_params()[1]
 9 
10     def get_params(self):
11         parser = optparse.OptionParser('Usage: <Program> -t target -p port')
12         parser.add_option('-t', '--target', dest='target', type='string', help='Specify target')
13         parser.add_option('-p', '--port', dest='port', type='int', help='Specify port to connect')
14         options, args = parser.parse_args()
15         if options.target is None or options.port is None:
16             print(parser.usage)
17             sys.exit()
18         return options.target, options.port
19     
20 
21     def run(self):
22         try:
23             client_s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
24             # client_s.settimeout(2)
25             client_s.connect((self.target, self.port))
26             # print(client_s.recv(4096).decode('utf-8'))
27             send_data = "GET / HTTP/1.1\r\nUser-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:100.0) Gecko/20100101 Firefox/100.0\r\n\r\n"
28             client_s.send(send_data.encode('utf-8'))            
29             recv_data = ""
30             while True:
31                 data = client_s.recv(1024).decode('utf-8')
32                 if len(data) == 0:
33                     break
34                 recv_data = recv_data + data
35             print(recv_data)
36         except Exception as e:
37             print(e)
38             sys.exit()
39 
40 if __name__ == '__main__':
41     tcpclient = TCPClient()
42     tcpclient.run()

 运行结果：

# python tcp_client.py -t 192.168.140.144 -p 80
HTTP/1.1 400 Bad Request
Date: Tue, 31 May 2022 09:46:21 GMT
Server: Apache/2.2.8 (Ubuntu) DAV/2
Content-Length: 323
Connection: close
Content-Type: text/html; charset=iso-8859-1

<!DOCTYPE HTML PUBLIC "-//IETF//DTD HTML 2.0//EN">
<html><head>
<title>400 Bad Request</title>
</head><body>
<h1>Bad Request</h1>
<p>Your browser sent a request that this server could not understand.<br />
</p>
<hr>
<address>Apache/2.2.8 (Ubuntu) DAV/2 Server at metasploitable.localdomain Port 80</address>
</body></html>

 

posted @ 2022-05-31 17:51  Jason_huawen  阅读(67)  评论(0)    收藏  举报