How to implement UDP client and send data in Swift on iPhone?

Question

I want to develop UDP client and send data in Swift.

I have reference the following link:

Swift: Receive UDP with GCDAsyncUdpSocket

Retrieving a stri

Answer 1

This looks like a dupe to Swift UDP Connection.

Refactoring the example a little bit:

let INADDR_ANY = in_addr(s_addr: 0)

udpSend("Hello World!", address: INADDR_ANY, port: 1337)

func udpSend(textToSend: String, address: in_addr, port: CUnsignedShort) {
  func htons(value: CUnsignedShort) -> CUnsignedShort {
    return (value << 8) + (value >> 8);
  }

  let fd = socket(AF_INET, SOCK_DGRAM, 0) // DGRAM makes it UDP

  var addr = sockaddr_in(
    sin_len:    __uint8_t(sizeof(sockaddr_in)),
    sin_family: sa_family_t(AF_INET),
    sin_port:   htons(port),
    sin_addr:   address,
    sin_zero:   ( 0, 0, 0, 0, 0, 0, 0, 0 )
  )

  textToSend.withCString { cstr -> Void in
    withUnsafePointer(&addr) { ptr -> Void in
      let addrptr = UnsafePointer(ptr)
      sendto(fd, cstr, strlen(cstr), 0, addrptr, socklen_t(addr.sin_len))
    }
  }

  close(fd)
}

If you have the target IP as a string, use inet_pton() to convert it to an in_addr. Like so:

var addr = in_addr()
inet_pton(AF_INET, "192.168.0.1", &buf)

Feel free to steal code from over here: SwiftSockets

Oh, and if you plan to do any serious network programming, grab this book: Unix Network Programming