A Simple Synchronous Server

SourcePro Net : Essential Networking Module User’s Guide : PART II The Networking Package : Servers : A Simple Synchronous Server

The primary job of a server is to accept client connections. This can be done through the use of the Berkeley Socket Adapter. Example 16 shows a simple daytime server:

Example 16 – Daytime Server

#include <rw/tools/datetime.h>

#include <rw/cstring.h>

#include <rw/network/RWSocket.h>

#include <rw/network/RWInetAddr.h>

#include <rw/network/RWWinSockInfo.h>

int main(void)

{

RWWinSockInfo winsock; // 1

RWInetAddr addr(1025); // 2

RWSocket sock;

sock.listen(addr); // 3

do {

RWSocket conn = sock.accept(); // 4

RWDateTime now = RWDateTime::now(); // 5

RWCString response = now.asString(); // 6

conn.sendAtLeast(response); // 7

conn.close(); // 8

} while(1);

sock.close();

return 0;

}

//1 Initializes the winsock library if appropriate (Windows platform only)

//2 Creates an address object, which represents the IP address and port number that this server will be waiting for client connections on.

//3 Binds the server side socket to the address constructed in the first step.

//4 Waits for an incoming connection, assigning that connection to conn for later use.

//5 Constructs a time object, which represents the current date and time.

//6 Formats the time object as a string so we can easily send it to the client.

//7 Send the response.

//8 Close the connection to the client and wait for further client connections.

Example 16 could be further extended to provide some exception handling. Placing a simple try/catch inside the loop allows for communication errors to be easily handled, as illustrated below:

do {

RWSocket conn = sock.accept();

RWDateTime now = RWDateTime::now();

RWCString response = now.asString();

try {

conn.sendAtLeast(response);

} catch(const RWxmsg& m) {

cout << "Exception: " << m.why() << endl;

}

conn.close();

} while(1);