NetUdp : Provide Udp Socket fully exposed to Qml.

OlivierLdff

NetUdp provide a Udp Socket that can send and receive Datagram.

Code is available here. Full documentation is inside readme.

Features

Support Unicast/Multicast/Broadcast Datagram.
C++ and Qml API.
Watcher that restart internal socket if something went wrong with the operating system.
- Retry binding to local port periodically if it failed.
- Watch network interfaces connection/disconnection to subscribe to multicast groups
- Send multicast datagram to every network interfaces by default, not only the default one.
Worker can optionnaly be moved in a worker thread to perform serialization/deserialization/crc checks etc ...
Ready to be inherited for more complex behavior
Provide counter of rx/tx data (number of packets, number of bytes sent in total, current bandwidth in bytes/s, ...)

Qml Usage

net::udp::registerQmlTypes(); should be called in the main to register qml types.

Unicast Datagram

This example show how to send a unicast datagram as a string to 127.0.0.1:9999. Don't forget to start the socket before sending any messages.

import QtQuick 2.0
import QtQuick.Controls 2.0

import NetUdp 1.0 as NetUdp

Button
{
  text: "send unicast"
  onClicked: () => socket.sendDatagram({
    address: "127.0.0.1",
    port: 9999,
    data: "My Data"
    // Equivalent to 'data: [77,121,32,68,97,116,97]'
  })

  NetUdp.Socket
  {
    id: socket
    Component.onCompleted: () => start()
  }
}

This example show how to receive the datagram. Don't forget to start listening to an address and a port. The datagram is always received as a string. It can easily be decoded to manipulate a byte array.

import NetUdp 1.0 as NetUdp

NetUdp.Socket
{
  onDatagramReceived: function(datagram)
  {
    console.log(`datagram : ${JSON.stringify(datagram)}`)
    console.log(`datagram.data (string) : "${datagram.data}"`)
    let byteArray = []
    for(let i = 0; i < datagram.data.length; ++i)
      byteArray.push(datagram.data.charCodeAt(i))
    console.log(`datagram.data (bytes): [${byteArray}]`)
      
    console.log(`datagram.destinationAddress : ${datagram.destinationAddress}`)
    console.log(`datagram.destinationPort : ${datagram.destinationPort}`)
    console.log(`datagram.senderAddress : ${datagram.senderAddress}`)
    console.log(`datagram.senderPort : ${datagram.senderPort}`)
    console.log(`datagram.ttl : ${datagram.ttl}`)
  }

  Component.onCompleted: () => start("127.0.0.1", 9999)
}

Multicast Datagram

Send multicast datagram work almost the same as unicast. Only difference is that you control on which interface the data is going.

import NetUdp 1.0 as NetUdp

NetUdp.Socket
{
  id: socket
  // A Packet will be send to each interface
  // The socket monitor for interface connection/disconnection
  multicastOutgoingInterfaces: [ "lo", "eth0" ]
  // Required in unix world if you want loopback on the same system
  multicastLoopback: true
    
  Component.onCompleted: () => start()
}

Then send data like in unicast:

socket.sendDatagram({
  address: "239.1.2.3",
  port: 9999,
  data: "My Data"
})

To receive it, subscribe the to the multicast group and choose on which interfaces.

import NetUdp 1.0 as NetUdp

NetUdp.Socket
{
  multicastGroups: [ "239.1.3.4" ]
  multicastListeningInterfaces: [ "lo", "eth0" ]
    
  // Required in the windows world if you want loopback on the same system
  multicastLoopback: true

  onDatagramReceived: (datagram) => console.log(`datagram : ${JSON.stringify(datagram)}`)

  // Listen port 9999
  Component.onCompleted: () => start(12999934)
}

Feel free to improve/fork/submit ideas.

mrjj

Thank you for sharing ❤