Why client/server mechanism (using socket's) doesn't work?

问题

I have free account on www.pythonanywhere.com. I have a server written on c++

some_space::socket_server::socket_server(unsigned int port):
     m_port(port),
     m_tcp_fd(0),
     m_udp_fd(0),
     m_newfd(0)
 {
     m_addr.sin_family = AF_INET;
     m_addr.sin_addr.s_addr = htonl(INADDR_ANY);
     m_addr.sin_port = htons(m_port);
 }

 void some_space::socket_server::set_port(unsigned int port)
 {
     assert(port != 0);
     m_port = port;
 }

 int some_space::socket_server::create_tcp_connection()
 {
         m_tcp_fd = socket(AF_INET, SOCK_STREAM, 0); 
         if(m_tcp_fd < 0) {
             perror("Error: Cannot set up the communication");
             return -1; 
         }   
         int status = bind(m_tcp_fd, (struct sockaddr *)&m_addr, sizeof(m_addr));       if(status < 0) {
             perror("Error: Cannot set up the communication");
             return -1;
         }
         status = listen(m_tcp_fd, 5);
         if(status == 0) {
             m_newfd = accept(m_tcp_fd, (struct sockaddr*)NULL, NULL);// ####################### The code freezes here (on the accept)
             if(m_newfd != -1) {
                 return m_newfd;
             }
             perror("Error: Cannot accept the connection");
             return -1;
         }
         perror("Error: The port cannot be listened");
         return -1;
     }

Where m_port = 9999 This cod is runed on .pythonanywhere.com server terminal.

And in the main.

    some_space::socket_server* s = new some_space::socket_server(9999);
     assert(s != 0);
     int r = s->create_tcp_connection(); // it it freezes in this function
     assert(r != -1);
     std::string rsp("");
     s->recv_response(rsp);
     std::string rec("some data");
     const char* t = rec.c_str();
     char* buf = const_cast<char*>(t);
     int size = rec.length();
     r = s->send_data(buf, size);
     assert(r != -1);*/
.......................

Also, I have a client program in my local pc written on python.

#!/usr/bin/env python

 import socket

 sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)     
 sock.connect(('<username>.pythonanywhere.com', 9999))
 sock.send('hello, world!')     
 data = sock.recv(1024)     
 print "receive >>> %s" % data     
 sock.close()

But the problem is the client can't connect with the server, it waits always. Where is a problem?

回答1:

PythonAnywhere dev here: PythonAnywhere only supports web apps using the Python WSGI protocol, which covers almost all of the main Python web frameworks (Django, web2py, Flask, Bottle, etc) but won't work with your own C-based server.

来源：https://stackoverflow.com/questions/28528086/why-client-server-mechanism-using-sockets-doesnt-work

标签

python

c++

sockets

web

client-server