socketServerExample.cpp

ArSocket example server program

This is an example to show how to use ArSocket. a server. This is the server program. The client is socketClientExample.cpp

This program opens a server on port 7777. It waits for the client to connect and says hello to the client. It then waits for the client to say hello and then exits.

First run this server program. Then run the client program, socketClientExample, perhaps in a different terminal window. You should see the server accept the connection, send its greeting to the client, recieve a response from the client, and then the connection closes.

This server only accepts one client connection, and then it exits. In practice, most servers would loop, accepting many clients, and simultaneously handling curently open client connections. You can use threads to do that (see ArASyncTask), but ArSocket is not inherently thread-safe, you would also need to use an ArMutex object to protect ArSocket calls.

See also:

ArSocket

socketClientExample.cpp

Also see the ArNetServer to help manage a server, or the ArNetworking library for a more complete networking framework.

#include "Aria.h"


int main()
{
  // The string to send to the client. 
  char *strToSend="Hello Client";
  // The buffer in which to recieve the hello from the client
  char buff[100];
  // The size of the string the client sent
  size_t strSize;

  // The socket objects: one for accepting new client connections,
  // and another for communicating with a client after it connects.
  ArSocket serverSock, clientSock;

  // Initialize Aria.  This is especially essential on Windows,
  // because it will initialize Windows's sockets sytem.
  Aria::init();

  // Open the server socket
  if (serverSock.open(7777, ArSocket::TCP))
    ArLog::log(ArLog::Normal, "socketServerExample: Opened the server port.");
  else
  {
    ArLog::log(ArLog::Normal, "socketServerExample: Failed to open the server port: %s.",
       serverSock.getErrorStr().c_str());
    return(-1);
  }

  for(int clientNo = 0; Aria::getRunning(); ++clientNo)
  {

    // Wait for a client to connect to us.
    ArLog::log(ArLog::Normal, "socketServerExample: Waiting for a client to connect. Press CTRL-C to exit.");

    if (serverSock.accept(&clientSock))
      ArLog::log(ArLog::Normal, "socketServerExample: Client %d has connected.", clientNo);
    else
      ArLog::log(ArLog::Terse, "socketServerExample: Error in accepting a connection from the client: %s.",
         serverSock.getErrorStr().c_str());

    // Send the string 'Hello Client' to the client. write() should
    // return the same number of bytes that we told it to write. Otherwise,
    // its an error condition.
    if (clientSock.write(strToSend, strlen(strToSend)) == strlen(strToSend))
      ArLog::log(ArLog::Normal, "socketServerExample: Said hello to the client.");
    else
    {
      ArLog::log(ArLog::Normal, "socketServerExample: Error in sending hello string to the client.");
      return(-1);
    }

    // Read data from the client. read() will block until data is
    // received. 
    strSize=clientSock.read(buff, sizeof(buff));

    // If the amount read is 0 or less, its an error condition.
    if (strSize > 0)
    {
      // Terminate the string with a NULL character.
      buff[strSize]='\0';
      ArLog::log(ArLog::Normal, "socketServerExample: Client said: %s.", buff);
    }
    else
    {
      ArLog::log(ArLog::Normal, "socketServerExample: Error in waiting/reading the hello from the client.");
      return(-1);
    }

    // Now lets close the connection to the client
    clientSock.close();
    ArLog::log(ArLog::Normal, "socketServerExample: Socket to client closed.");
    
  }

  // And lets close the server port
  serverSock.close();
    ArLog::log(ArLog::Normal, "socketServerExample: Server socket closed.");


  // Uninitialize Aria
  Aria::uninit();

  // All done
  return(0);
}

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