Socket chat system - broadcasting them to all clients - c++

Question

Communication between a server and a clients works, but the server don't forward the client messages to the other connected client's, but only to the sender.
i want the server react to incoming messages by broadcasting them to all clients like a chat system, but keep my command system without sharring it with all clients, but with with sender.
down below is the sources:
server
/*server*/
#define WIN32_LEAN_AND_MEAN
#include <iostream>
#include <string>
#include <windows.h>
#include <winsock2.h>
#include <ws2tcpip.h>
#include <stdlib.h>
#include <stdio.h>
#include <process.h>
// 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 PORT "3490"
#define SERVER "localhost"
#include <time.h>
WSADATA wsa;
SOCKET s , new_socket;
struct sockaddr_in server , client;
int c;
char *message;
std::string line;
DWORD WINAPI ProcessClient (LPVOID lpParameter)
{
SOCKET AcceptSocket = (SOCKET) lpParameter;
// Send and receive data.
int bytesSent;
int bytesRecv = SOCKET_ERROR;
char sendbuf[2000]="";
char sendbuf2[2000]="";
char recvbuf[2000]="";
char timebuf[128];
sprintf(sendbuf, "Hello, it's a test server at %s:%d (commands: 1, 2, exit)\n", SERVER, PORT);
bytesSent = send( AcceptSocket, sendbuf, strlen(sendbuf), 0);
if (bytesSent == SOCKET_ERROR)
{
printf( "Error at send hello: %ld\n", WSAGetLastError());
goto fin;
}
while (1)
{
_strtime( timebuf );
ZeroMemory (recvbuf, sizeof(recvbuf));
bytesRecv = recv( AcceptSocket, recvbuf, 32, 0);
printf( "%s Client said: %s\n", timebuf, recvbuf);
sprintf(sendbuf, "%s Client said: %s\n", timebuf, recvbuf);
bytesSent = send( AcceptSocket, sendbuf, strlen(sendbuf), 0);
if (strcmp(recvbuf, "1") == 0)
{
sprintf(sendbuf, "You typed ONE\n");
//printf("Sent '%s'\n", sendbuf);
bytesSent = send( AcceptSocket, sendbuf, strlen(sendbuf), 0);
if (bytesSent == SOCKET_ERROR)
{
printf( "Error at send: %ld\n", WSAGetLastError());
goto fin;
}
}
else if (strcmp(recvbuf, "2") == 0)
{
sprintf(sendbuf, "You typed TWO\n");
//printf("Sent '%s'\n", sendbuf);
bytesSent = send( AcceptSocket, sendbuf, strlen(sendbuf), 0);
if (bytesSent == SOCKET_ERROR)
{
printf( "Error at send: %ld\n", WSAGetLastError());
goto fin;
}
}
else if (strcmp(recvbuf, "exit") == 0)
{
printf( "Client has logged out\n", WSAGetLastError());
goto fin;
}
else
{
// sprintf(sendbuf, "unknown command\n");
//printf("Sent '%s'\n", sendbuf);
// bytesSent = send( AcceptSocket, sendbuf, strlen(sendbuf), 0);
if (bytesSent == SOCKET_ERROR)
{
// printf( "Error at send: %ld\n", WSAGetLastError());
goto fin;
}
}
}
fin:
printf("Client processed\n");
closesocket(AcceptSocket);
return 0;
}
int main(int argc , char *argv[])
{
std::cout << ("\nInitialising Winsock...");
if (WSAStartup(MAKEWORD(2,2),&wsa) != 0)
{
std::cout << ("Failed. Error Code : %d",WSAGetLastError());
return 1;
}
printf("Initialised.\n");
//Create a socket
if((s = socket(AF_INET , SOCK_STREAM , 0 )) == INVALID_SOCKET)
{
std::cout << ("Could not create socket : %d" , WSAGetLastError());
}
std::cout << ("Socket created.\n");
//Prepare the sockaddr_in structure
server.sin_family = AF_INET;
server.sin_addr.s_addr = INADDR_ANY;
server.sin_port = htons( 3490 );
//Bind
if( bind(s ,(struct sockaddr *)&server , sizeof(server)) == SOCKET_ERROR)
{
std::cout << ("Bind failed with error code : %d" , WSAGetLastError());
exit(EXIT_FAILURE);
}
puts("Bind done");
//Listen to incoming connections
listen(s , 3);
//Accept and incoming connection
std::cout << ("Waiting for incoming connections...");
c = sizeof(struct sockaddr_in);
while(true){
while((new_socket = accept(s , (struct sockaddr *)&client, &c)) != INVALID_SOCKET) {
// Create a new thread for the accepted client (also pass the accepted client socket).
printf( "Client Connected.\n");
DWORD dwThreadId;
CreateThread (NULL, 0, ProcessClient, (LPVOID) new_socket, 0, &dwThreadId);
}
}
if (new_socket == INVALID_SOCKET)
{
std::cout << ("accept failed with error code : %d" , WSAGetLastError());
return 1;
}
closesocket(s);
WSACleanup();
return 0;
}
client
/*client*/
#define WIN32_LEAN_AND_MEAN
#pragma comment(lib,"ws2_32.lib")
#include <iostream>
#include <process.h>
#include <string>
#include <winsock2.h>
SOCKET Socket;
#define SERVER "localhost"
int PORT = 3490;
std::string line;
bool chat = false;
class Buffer
{
public:
int ID;
char Message[256];
}sbuffer;
int ClientThread()
{
char buffer[2000]= "";
for(;; Sleep(10))
{
if(recv(Socket, buffer, sizeof(sbuffer), NULL)!=SOCKET_ERROR)
{
strncpy(sbuffer.Message, buffer, sizeof(sbuffer.Message));
std::cout << "<Client:" << sbuffer.ID << ":> " << sbuffer.Message <<std::endl;
ZeroMemory (buffer, sizeof(buffer));
}
}
return 0;
}
int main(void)
{
WSADATA WsaDat;
if(WSAStartup(MAKEWORD(2,2),&WsaDat)!=0)
{
std::cout<<"Winsock error - Winsock initialization failed\r\n";
WSACleanup();
system("PAUSE");
return 0;
}
// Create our socket
Socket=socket(AF_INET,SOCK_STREAM,IPPROTO_TCP);
if(Socket==INVALID_SOCKET)
{
std::cout<<"Winsock error - Socket creation Failed!\r\n";
WSACleanup();
system("PAUSE");
return 0;
}
// Resolve IP address for hostname
struct hostent *host;
if((host=gethostbyname(SERVER))==NULL)
{
std::cout<<"Failed to resolve hostname.\r\n";
WSACleanup();
system("PAUSE");
return 0;
}
// Setup our socket address structure
SOCKADDR_IN SockAddr;
SockAddr.sin_port=htons(PORT);
SockAddr.sin_family=AF_INET;
SockAddr.sin_addr.s_addr=*((unsigned long*)host->h_addr);
// Attempt to connect to server
if(connect(Socket,(SOCKADDR*)(&SockAddr),sizeof(SockAddr))!=0)
{
std::cout<<"Failed to establish connection with server\r\n";
WSACleanup();
system("PAUSE");
return 0;
}
// If iMode!=0, non-blocking mode is enabled.
u_long iMode=1;
ioctlsocket(Socket,FIONBIO,&iMode);
// Main loop
for(;;)
{
// Display message from server
char buffer[1000];
memset(buffer,0,999);
int inDataLength=recv(Socket,buffer,1000,0);
std::cout<<buffer;
CreateThread(NULL, NULL, (LPTHREAD_START_ROUTINE) ClientThread, NULL, NULL, NULL);
for(;; Sleep(10))
{
std::string buffer;
std::getline(std::cin, buffer);
if (send(Socket, buffer.c_str(), buffer.length(), NULL) < 1){
}
}
int nError=WSAGetLastError();
if(nError!=WSAEWOULDBLOCK&&nError!=0)
{
std::cout<<"Winsock error code: "<<nError<<"\r\n";
std::cout<<"Server disconnected!\r\n";
// Shutdown our socket
shutdown(Socket,SD_SEND);
// Close our socket entirely
closesocket(Socket);
break;
}
Sleep(1000);
}
WSACleanup();
system("PAUSE");
return 0;
}
Please help me fix it, i'm new into socket's. Show me how to do as i'm going understand better with code and it will also be usefull to others who might need it in the future.

Answer 1

If you need the server to communicate with multiple clients, then you need some kind of collection of all the connected clients. Then it's easy to send to all connections, or send to all connection but the originating connection.
How to do it will differ vastly between C and C++, but for C++ look into structures and std::vector.
In pseudo-code it would be something like this:
while (run_server)
{
poll_all_connections();
if (have_new_connection())
{
accept_new_connection();
add_connection_in_collection();
}
else
{
for (connection in all_connections())
{
if (have_input(connection))
{
input = read_from_connection(connection);
for (send_to in all_connections())
write_to_connection(connection, input)
}
}
}
}
If you implement the above pseudo-code, then input from any connection will be sent to all connections.
Don't forget to remove a connection from the collection if the connection is broken (error or disconnect.)

Answer 2

You have to maintain a list of all the client socket connections then send the data to each client one by one.
or you can use threading to implement this as follows :-
Server-thread()
{
while(true)
{
/// Accept Connection in ClientSocket.
HandleClient-Thread(ClientSocket) ; // launch a thread for each client .
}
}
HandleClient-Thread(ClientSocket)
{
// handle this client here
}