Capacitor UDP

UDP Plugin for Capacitor inspired from cordova-plugin-chrome-apps-sockets-udp! Support both IPv6 and IPv4, multicast and broadcast!

For debugging, check out the Udper app developed using this plugin! https://play.google.com/store/apps/details?id=xyz.chenzhongkai.udper&hl=en_US

With capacitor, it is possible to write following code:

async function process (){
    try {
        await UdpPlugin.closeAllSockets();
        let info = await UdpPlugin.create();
        await UdpPlugin.bind({ socketId: info.socketId, port: 5500})
        await UdpPlugin.send({ socketId: info.socketId, address: targetAddress, port: 6000, buffer: UdpPluginUtils.bufferToString(data)}) })
    } catch {
        //........
    }
}
 

Isn't it amazing!

Install

$ npm install capacitor-udp

For android development, don't forget to add the plugin class in the MainActivity!

TypeScript Special Mention!!!

declare module '@capacitor/core'

sometimes fail to work as expected. I guess the dirty solution like changing the core-plugin-definitions.ts might be the most trust-worthy solution.

For instance,

import { Plugin, PluginListenerHandle } from './definitions';
import {IUdpPlugin} from "capacitor-udp"
export interface PluginRegistry {
    Accessibility: AccessibilityPlugin;
    App: AppPlugin;
    BackgroundTask: BackgroundTaskPlugin;
    Browser: BrowserPlugin;
    // .............
    UdpPlugin:IUdpPlugin;
    [pluginName: string]: {
        [prop: string]: any;
    };
}

Usage

import { Plugins } from "@capacitor/core";
const { UdpPlugin } = Plugins;
import {UdpPluginUtils} from "capacitor-udp"; // if you want support for converting between ArrayBuffer and String

For intellisense or typescript, you might need to edit the file in @capacitor/core/dist/esm/core-plugin-definitions.ts. Make sure that this file is actually loaded, since there might be other node_modules folders.

API Reference

The api is to some extent similar to Chrome UDP API , but with the taste of capacitor!

• create
• update
• bind
• send
• close
• closeAllSockets
• setBroadcast
• getSockets
• joinGroup
• leaveGroup
• getJoinedGroups
• setPaused
• setMulticastLoopbackMode

Events:

• receive
• receiveError

Create

Create a socket for udp, and you can create more than one differentiated by the socket id.

UdpPlugin.create({properties: { name: "yourSocketName", bufferSize: 2048 }} ).then(res=>{socketId = res.socketId});

Update

Update the socket info including socket name and buffer size.

UdpPlugin.update( {socketId: yourSocketId, properties: { name: "socketname", bufferSize: 2048 }} )

Bind

You need to bind a socket before sending and receiving data.

UdpPlugin.bind({ socketId: yourSocketId, port: 5000})

Send

Capacitor doesn't support Arraybuffer for now, so I need to convert ArrayBuffer to base64 string. I have provided a util function to help you achieve that!

UdpPlugin.send({ socketId: yourSocketId, address: targetAddress, port: 6000, buffer: bufferString}) // bufferString is of type string
UdpPlugin.send({ socketId: yourSocketId, address: targetAddress, port: 6000, buffer: UdpPluginUtils.bufferToString(data)}) // data is of type ArrayBuffer

Close

Close one socket

UdpPlugin.close({ socketId: yourSocketId }) 

Close All Sockets

UdpPlugin.closeAllSockets() 

Set Broadcast

After enabling broadcasting, you can send data with target address 255.255.255.255.

UdpPlugin.setBroadcast({socketId: yourSocketId,enabled: enableBroadcastOrNot}) 

Get Sockets

Obtain all the sockets available.

UdpPlugin.getSockets().then(res=>{
    //res contains sockets...
})

Join Group

Join a particular group address. For IPv4, it's like "238.12.12.12". For IPv6, it's like "ff02::08".

UdpPlugin.joinGroup({socketId: yourSocketId, address: multicastAddress})

Leave Group

UdpPlugin.leaveGroup({socketId: yourSocketId, address: multicastAddress})

Get Joined Groups

UdpPlugin.getJoinedGroups({ socketId: yourSocketId }).then(res=>{
    // res contains your group addresses
})

Set Paused

Pause receiving data.

UdpPlugin.setPaused({socketId: yourSocketId,paused: pauseOrNot})

Set Multicast Loopback Mode

UdpPlugin.setMulticastLoopbackMode({socketId: yourSocketId, enabled: enabledOrNot})

Receive Event

UdpPlugin.addListener("receive", data => {
    yourArrayBuffer = UdpPluginUtils.stringToBuffer(data)
}});

For understanding ArrayBuffer, you can refer to Typed Arrays

Receive Error Event

UdpPlugin.addListener("receiveError", error => {console.log(error)});