Python socket module. Connecting to an HTTP proxy

问题:

To begin with, I understand there are other modules such as Requests that would be better suited and simpler to use, but I want to use the socket module to better understand HTTP.

I have a simple script that does the following:

Client ---> HTTP Proxy ---> External Resource (GET Google.com)

I am able to connect to the HTTP proxy alright, but when I send the GET request headers for google.com to the proxy, it doesn't serve me any response at all.

#!/usr/bin/python
import socket
import sys



headers = """GET / HTTP/1.1\r\n
Host: google.com\r\n\r\n"""



socket = socket

host = "165.139.179.225" #proxy server IP
port = 8080              #proxy server port

try:
    s = socket.socket()
    s.connect((host,port))
    s.send(("CONNECT {0}:{1} HTTP/1.1\r\n" + "Host: {2}:    {3}\r\n\r\n").format(socket.gethostbyname(socket.gethostname()),1000,port,host))
    print s.recv(1096)
    s.send(headers)
    response = s.recv(1096)
   print response
   s.close()
except socket.error,m:
   print str(m)
   s.close()
   sys.exit(1)

回答1:

To make a HTTP request to a proxy open a connection to the proxy server and then send a HTTP-proxy request. This request is mostly the same as the normal HTTP request, but contains the absolute URL instead of the relative URL, e.g.

 > GET http://www.google.com HTTP/1.1
 > Host: www.google.com
 > ...

 < HTTP response

To make a HTTPS request open a tunnel using the CONNECT method and then proceed inside this tunnel normally, that is do the SSL handshake and then a normal non-proxy request inside the tunnel, e.g.

 > CONNECT www.google.com:443 HTTP/1.1
 >
 < .. read response to CONNECT request, must be 200 ...

 .. establish the TLS connection inside the tunnel

 > GET / HTTP/1.1
 > Host: www.google.com

回答2:

Python 3 requires the request to be encoded. Thus, expanding on David's original code, combined with Steffens answer, here is the solution written for Python 3:

def connectThroughProxy():
    headers = """GET http://www.example.org HTTP/1.1
                Host: www.example.org\r\n\r\n"""

    host = "192.97.215.348" #proxy server IP
    port = 8080              #proxy server port

    try:
        s = socket.socket()
        s.connect((host,port))
        s.send(headers.encode('utf-8'))
        response = s.recv(3000)
        print (response)
        s.close()
    except socket.error as m:
       print (str(m))
       s.close()
       sys.exit(1) 

This allows me to connect to the example.org host through my corporate proxy (at least for non SSL/TLS connections).