source: tools/SocketClient/SocketClient.cpp@ 15

/********************************************************************\

  Generic example for remote control via a socket interface
  
  Oliver Grimm, March 2009

\********************************************************************/

#include <iostream>
#include <sys/socket.h>
#include <netdb.h>
#include <signal.h>

#define MAX_COM_SIZE 10000

int main(int argc, char *argv[]) {
        
  char Buffer[MAX_COM_SIZE],ServerName[MAX_COM_SIZE]="eth-vme02";
  int SocketDescriptor, DAQPort = 2000;
  struct sockaddr_in SocketAddress;
  fd_set ReadFileDescriptor;
  
  printf("+++ Command line socket interface +++\n");
  if (argc != 3) {
    printf("Usage: %s <server name> <port>\n", argv[0]);
    printf("Taking defaults: <%s> <%d>\n", ServerName, DAQPort);
  } 
  else {
    sprintf(ServerName,argv[1]);
    DAQPort = atoi(argv[2]);
  }
  
  // Open socket descriptor
  if ((SocketDescriptor = socket(PF_INET, SOCK_STREAM, 0)) == -1) {
    printf("Error: Could not open socket.");
    exit(EXIT_FAILURE);
  }
    
  // Resolve hostname and try to connect to server
  struct hostent *hostent = gethostbyname(ServerName);
  if (hostent==0) {
    printf("\nCould not resolve host name.\n");
    close(SocketDescriptor);
    exit(EXIT_FAILURE);
  }

  SocketAddress.sin_family = PF_INET;
  SocketAddress.sin_port = htons((unsigned short) DAQPort);
  SocketAddress.sin_addr = *(struct in_addr*) hostent->h_addr;
  
  if (connect(SocketDescriptor, (struct sockaddr *) &SocketAddress, sizeof(SocketAddress))==-1) {
    printf("Error: Could not connect to server %s (port %d)\n", ServerName, DAQPort);
    close(SocketDescriptor);
    exit(EXIT_FAILURE);
  }
  printf("\nConnected to %s (port %d).\n"
         "Type 'exit' to quit.\n", ServerName, DAQPort);
  signal(SIGPIPE,SIG_IGN);  // Do not kill process if writing to closed socket

  while(true) {
    printf("> ");       fflush(stdout);
    
    // Wait for data either from terminal (stdin) or from socket
    FD_ZERO(&ReadFileDescriptor);   
    FD_SET(SocketDescriptor, &ReadFileDescriptor);
    FD_SET(STDIN_FILENO, &ReadFileDescriptor);
    if (select(((int) SocketDescriptor)+1, &ReadFileDescriptor, NULL, NULL, NULL)==-1) {
      perror("Error with select()");
      break;
    }
    memset(Buffer, 0, sizeof(Buffer));
    if (FD_ISSET(STDIN_FILENO, &ReadFileDescriptor)) { // Data from stdin
      fgets(Buffer, MAX_COM_SIZE, stdin);
      if (!strcmp(Buffer,"exit\n")) break;
      if ((write(SocketDescriptor, Buffer, strlen(Buffer)))<1) // Write command to socket
        printf("Error: Could not write command to socket.\n");
    }
    else if (FD_ISSET(SocketDescriptor, &ReadFileDescriptor)) { // Data from socket
      memset(Buffer, 0, sizeof(Buffer));
      if(read(SocketDescriptor, Buffer, MAX_COM_SIZE)==0) {
        printf("Server not exisiting anymore, exiting...\n");
        break;
      }
      printf("\r%s", Buffer);
    }  
  }

  // Close socket descriptor
  if (!close(SocketDescriptor)) printf("Connection to %s closed.\n", ServerName);

  exit(EXIT_SUCCESS);
}