custom_tcp_client.cpp

/// another dummy tcpclient
///g++ client.cpp -oclient -lwsock32 -lws2_32

#define WIN32_LEAN_AND_MEAN

#include <windows.h>
#include <winsock2.h>
#include <ws2tcpip.h>

#include <stdlib.h>
#include <stdio.h>
#include <string>
using std::string;


// Need to link with Ws2_32.lib, Mswsock.lib, and Advapi32.lib
#pragma comment (lib, "Ws2_32.lib")
#pragma comment (lib, "Mswsock.lib")
#pragma comment (lib, "AdvApi32.lib")


#define DEFAULT_BUFLEN 512
#define DEFAULT_PORT "22"

struct WinsockInitIO{
    WinsockInitIO(){
         WSADATA wsaData;
    int iResult = WSAStartup(MAKEWORD(2,2), &wsaData);
    if (iResult != 0) {
        printf("WSAStartup failed with error: %d\n\n", iResult);
        return ;
    }

    }
    ~WinsockInitIO(){
    WSACleanup();
    }

};

WinsockInitIO object;

SOCKET connecto_to(const char *address, const char *port)
{
 
    SOCKET ConnectSocket = INVALID_SOCKET;
    struct addrinfo *result = NULL,
                    *ptr = NULL,
                    hints;
   
    char recvbuf[DEFAULT_BUFLEN]={0};
    int iResult;
    int recvbuflen = DEFAULT_BUFLEN;
    if (address ==nullptr) {
        printf("usage: %s server-name\n");
        return -1;
    }

    ZeroMemory( &hints, sizeof(hints) );
    hints.ai_family = AF_UNSPEC;
    hints.ai_socktype = SOCK_STREAM;
    hints.ai_protocol = IPPROTO_TCP;
    iResult = getaddrinfo(address, ((port==nullptr)?DEFAULT_PORT:port), &hints, &result);
    if ( iResult != 0 ) {
        printf("getaddrinfo failed with error: %d\n", iResult);
        return -1;
    }

	 
	int point = 1;
    for(ptr=result; ptr != NULL ;ptr=ptr->ai_next) {
        ConnectSocket = socket(ptr->ai_family, ptr->ai_socktype, ptr->ai_protocol);
		
        if (ConnectSocket == INVALID_SOCKET) {
            printf("socket failed with error: %ld\n", WSAGetLastError());
            return -1;
        }

		 
		///inet_ntop(ptr->ai_family,ptr->ai_addr,ip,32);
		 sockaddr_in* addr=(sockaddr_in*)ptr->ai_addr;
		 char *ip = inet_ntoa(addr->sin_addr);
		 printf("IP To connect : %s\n",ip);
        // Connect to server.
        iResult = connect( ConnectSocket, ptr->ai_addr, (int)ptr->ai_addrlen);
		if(iResult == 0){
              printf("Connected\n");
			  freeaddrinfo(result);
			  return ConnectSocket;
		}
        if (iResult == SOCKET_ERROR) {
            closesocket(ConnectSocket);
            ConnectSocket = INVALID_SOCKET;
			printf("Connect failed number=>%d\n\n", point++);
            continue;
        }

        break;
    }

    freeaddrinfo(result);

    if (ConnectSocket == INVALID_SOCKET) {
        printf("Unable to connect to server!\n");
        return -1;
    }
   return ConnectSocket;
}


string recv_all(SOCKET so)
{
    int iResult=0;
    char recvbuf[8196]={0};
    string ret;
    do {

        iResult = recv(so, recvbuf, 8196, 0);
        if ( iResult > 0 )
           {
             printf("Bytes received: %d\n", iResult);
             ret+=recvbuf;
             memset(recvbuf,0,8196);            
           }
        else if ( iResult == 0 )
            printf("\nConnection closed\n");
        else
            printf("\n\nrecv failed with error: %d\n\n", WSAGetLastError());

    } while( iResult > 0 );
   return ret;
}

string send_request_command(SOCKET so, const char *cmd)
{
    int iResult = send( so, cmd, (int)strlen(cmd), 0 );
    if (iResult == SOCKET_ERROR) {
        printf("send failed with error: %d\n", WSAGetLastError());
        closesocket(so);
        return "";
    }
   return recv_all(so);
}



int  main(int argc, char **argv) 
{
    SOCKET ConnectSocket = connecto_to(argv[1], nullptr);
    if(ConnectSocket==-1){
		printf("Invalid socket");
		return -1;
	}
	else
	{
			string send_buffer;
			send_buffer += "Query here";
			
			printf("Request %s", send_buffer.c_str());
			string res = send_request_command(ConnectSocket,send_buffer.c_str());
			printf("Responde %s", res.c_str());		
	}
    closesocket(ConnectSocket);
    return 0;
}