Can't receive the response package by winsock2 from http server - http

Question

I'm sure my program has got the ip from the server by the url.
When I send the GET request, although it was successfully send, it couldn't get the response. I'm not sure if the server had gotten my request, how should I check if the server get my request?
The connection will close after sending a request and waiting for a period of time . The "recv" function will response 0, and the buffer get nothing.
I wonder if there are any error of my "sendbuf = GET / HTTP/1.1\r\n\r\n".
Should I use 1.1 or 1.0?
char *sendbuf = "GET / HTTP/1.1\r\n\r\n";
//to get the ip from DNS server
pHostEnt = gethostbyname( "www.google.com.tw");
ppaddr = (int**)pHostEnt->h_addr_list;
sockAddr.sin_addr.s_addr = **ppaddr;
printf("%s",inet_ntoa(sockAddr.sin_addr) );
//to create the socket and connect to it
memset(&serverAddress, 0, sizeof(serverAddress));
serverAddress.sin_family = AF_INET;
serverAddress.sin_addr.s_addr = inet_addr(inet_ntoa(sockAddr.sin_addr));
serverAddress.sin_port = htons(SERVER_PORT);
serverSocket = socket(AF_INET, SOCK_STREAM, 0);
connect(serverSocket, (struct sockaddr *)&serverAddress, sizeof(serverAddress));
//send request
int iResult = send( serverSocket, sendbuf, (int)strlen(sendbuf), 0 );
//get response
if (bytesRead=recv(serverSocket, buf, MAX_SIZE, 0) < 0)
printf("Error with send()");
else
printf("Successfully sent html fetch response");

Answer 1

Using HTTP 1.1 is fine, but your request is incomplete as HTTP 1.1 requires the Host header, at the very least (in order for servers to support virtual hosts).
More importantly, you are not doing any error handling. You need to do that.
You are also not taking into account that gethostname() can return multiple IP addresses. You need to connect() to each address until one succeeds, or until you exhaust the list.
Try this:
char *sendbuf = "GET / HTTP/1.1\r\nHost: www.google.com.tw\r\n\r\n";
//to get the ip from DNS server
pHostEnt = gethostbyname( "www.google.com.tw"); // you should be using getaddrinfo() instead!
if (!pHostEnd)
{
printf("Unable to resolve www.google.com.tw\n");
return; // or whatever...
}
if (pHostEnt->h_addrtype != AF_INET)
{
printf("www.google.com.tw did not resolve to an IPv4 IP address\n");
return; // or whatever...
}
serverSocket = socket(AF_INET, SOCK_STREAM, 0);
if (serverSocket == INVALID_SOCKET)
{
printf("Unable to create socket\n");
return; // or whatever...
}
in_addr **ppaddr = (in_addr**) pHostEnt->h_addr_list;
sockaddr_in serverAddress = {0};
serverAddress.sin_family = AF_INET;
serverAddress.sin_port = htons(SERVER_PORT);
bool connected = false;
int i = 0;
while (ppadd[i] != NULL)
{
// connect to server
serverAddress.sin_addr = *(ppaddr[i]);
printf("Connecting to %s\n", inet_ntoa(serverAddress.sin_addr);
if (connect(serverSocket, (struct sockaddr *)&serverAddress, sizeof(serverAddress)) == 0)
{
connected = true;
break;
}
if (WSAGetLastError() == WSAEWOULDBLOCK)
{
fd_set writefds;
FD_ZERO(&writefds);
FD_SET(serverSocket, &writefds);
timeval timeout;
timeout.tv_sec = 5;
timeout.tv_usec = 0;
if (select(0, NULL, &writefds, NULL, &timeout) > 0)
{
connected = true;
break;
}
}
++i;
}
if (!connected)
{
printf("Unable to connect to www.google.com.tw\n");
return; // or whatever...
}
printf("Connected, sending request\n");
//send request
char *ptr = sendbuf;
int len = strlen(sendbuf);
do
{
int bytesSent = send( serverSocket, ptr, len, 0 );
if (bytesSent > 0)
{
ptr += bytesSent;
len -= bytesSent;
continue;
}
if (WSAGetLastError() == WSAEWOULDBLOCK)
{
fd_set writefds;
FD_ZERO(&writefds);
FD_SET(serverSocket, &writefds);
timeval timeout;
timeout.tv_sec = 15;
timeout.tv_usec = 0;
if (select(0, NULL, &writefds, NULL, &timeout) > 0)
continue;
}
printf("Unable to send request\n");
return; // or whatever...
}
while (len > 0);
printf("Reading response\n");
//get response
do
{
int bytesRead = recv(serverSocket, buf, MAX_SIZE, 0);
if (bytesRead > 0)
{
// process buf as needed...
// make sure you are paying attention to the
// Content-Length and Transfer-Encoding headers,
// as they tell you how to read the response.
// Refer to RFC 2616 Section 4.4 for details...
contine;
}
if (bytesRead == 0)
{
printf("Disconnected");
return; // or whatever...
}
if (WSAGetLastError() == WSAEWOULDBLOCK)
{
fd_set readfds;
FD_ZERO(&readfds);
FD_SET(serverSocket, &readfds);
timeval timeout;
timeout.tv_sec = 15;
timeout.tv_usec = 0;
if (select(0, &readfds, NULL, NULL, &timeout) > 0)
continue;
}
printf("Unable to read response\n");
return; // or whatever...
}
while (true);
closesocket(serverSocket);