UDP testing

[shapemeister]

Hi,

I'm attempting to write working code that can pass strings over UDP. I am attempting to do this in objective C.

Here is the code for the server, written in java:


import java.net.*;

public class UDPServer {
public static void main(String[] args) throws Exception {
int port = 8000;
DatagramSocket sock = new DatagramSocket(port);
byte[] buf = new byte[1024];
DatagramPacket recvPacket = new DatagramPacket(buf, buf.length);
DatagramPacket sendPacket = null;

while (true) {
sock.receive(recvPacket);
String msg = new String(recvPacket.getData(), 0, recvPacket.getLength());
System.out.println("receive = " + msg + ", port = " + recvPacket.getPort());

if (msg.equals("end"))
break;

if (sendPacket == null) {
sendPacket = new DatagramPacket(msg.getBytes(), msg.getBytes().length, recvPacket.getAddress(), recvPacket.getPort());
}
else {
sendPacket.setData(msg.getBytes());
sendPacket.setAddress(recvPacket.getAddress());
}
sock.send(sendPacket);
}
}
}

Here is the code I am supposed to be writing that handles the client portion of the communication, written in java:

public class UDPClient {
public static void main(String[] args) throws Exception {
int port = 8000;
InetAddress addr = InetAddress.getByName("127.0.0.1");
DatagramSocket sock = new DatagramSocket();
BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
String line = null;
byte[] buf = new byte[1024];
DatagramPacket recvPacket = new DatagramPacket(buf, buf.length);
DatagramPacket sendPacket = null;

while ((line = reader.readLine()) != null) {
if (sendPacket == null) {
sendPacket = new DatagramPacket(line.getBytes(), line.getBytes().length, addr, port);
}
else {
sendPacket.setData(line.getBytes());
}
sock.send(sendPacket);

if (line.equals("end"))
break;

sock.receive(recvPacket);
String msg = new String(recvPacket.getData(), 0, recvPacket.getLength());
System.out.println("echo = " +msg);
}
}
}



Here is my rendering of the client code in Objective c:

- (void)viewDidLoad
{
[super viewDidLoad];
int port = 8000; // 포트번호
NSString *addr = @"127.0.0.1";
sock = [[AsyncUdpSocket alloc] initWithDelegate:self];
[sock bindToPortort error:nil];
[sock enableBroadcast:YES error:nil];
Byte buffer[1024];
NSData *recvPacket = [[NSData alloc] init];
recvPacket = [NSData dataWithBytesNoCopy:buffer length: 1024];
NSData * sendPacket = [[NSData alloc] initWithBytesNoCopy:buffer length:1024];
NSInputStream * stream = [[NSInputStream alloc] init];
while([stream read: buffer maxLength: 1024] != 0) {
NSString* string = [[NSString alloc] initWithBytes:buffer length:1024 encoding: NSASCIIStringEncoding];
if (string == @"end") break;
sendPacket = [NSData dataWithContentsOfFile:string];
[sock sendData:sendPacket toHost:addr portort withTimeout:-1 tag:1];
NSLog(@"1" );

NSString *msg = [NSString stringWithFormat:@"%@", recvPacket]; //forcing the NSData to become NSString
NSLog(@"%@",msg);
[sock receiveWithTimeout:-1 tag:1];
[string release];

}
[stream release];
}

sock is an instance variable in the header file, of type AsyncUdpSocket.


Why isn't this working?!??!?!?!

[mungbeans]

I've never used UDP before so can't answer that specifically.

However you've just posted a big chunk of code and said its not working.
What's not working? - you can't establish a connection?, you can but data doesn't get transmitted?, data does get transmitted but not the content you were expecting?, ....

If it were me running this code, the first thing I'd do is replace the error:nil lines with an error object and see if its successful.If not, look why not, if yes, move onto the next line and see if that works or not.

Can you even bind? You don't tell us. If not, look at why not. If yes, then what's the actual specific problem?

[Bopols]

Save yourself a lot of headaches and use AsyncUdpSocket
It's a wrapper class to hide all those low level CF socket calls.

AsyncUdpSocket.m - cocoaasyncsocket - AsyncSocket is an asynchronous socket networking library for Cocoa. - Google Project Hosting