Edge devices communicating through a private local area network

In this example, we will setup endpoint devices communicating with each other through a local area network using tcp.

The remote devices must be connected to the internet for authentication ensuring only authorized users can access the edge devices. This will also allow you to configure your edge endpoints and develop your applications using a browser interface.

Install m2m in your edge endpoints.

$ npm install m2m

Edge Server 1 Setup

1. Save the code below as server.js in your server 1 project directory.

const m2m = require('m2m')

// simulated voltage data source
function voltageSource(){
  return 50 + Math.floor(Math.random() * 10)
}

let edge = new m2m.Edge()

m2m.connect()
.then(console.log) // success
.then(() => {
    // edge tcp server - private LAN communication
  
    let port = 8125		        // port must be open from your endpoint
    let host = '127.0.0.1' 	        // localhost
    //let host = '192.168.0.114' 	// actual ip of server endpoint
    
    edge.createServer(port, host, (server) => {
    // or just  
    //edge.server({port:port, host:host}, (server) => {

      // server resources
      server.publish('edge-voltage', (tcp) => { // using default 5 secs or 5000 ms polling interval
         let vs = voltageSource()
         tcp.send({port:port, topic:tcp.topic, type:'voltage', value:vs})
      })

      server.dataSource('/machine-1', (tcp) => { // common resources both for client read and write method 
        let data = { id:tcp.id, rootTopic:tcp.rootTopic, subTopic:tcp.subTopic }
      
        if(tcp.topic === '/machine-1/sensor-1'){
          let rn = Math.floor(Math.random() * 200)
          data.type = 'sensor-1'
          data.value = rn 
        }
        else if(tcp.topic === '/machine-1/sensor-2'){
          let rn = Math.floor(Math.random() * 400)
          data.type = 'sensor-2'
          data.value = rn 
        }
        else if(tcp.topic === '/machine-1' && tcp.payload){
          data.type = tcp.payload.type
          data.value = tcp.payload.value
        }  
        tcp.send(data)
      })
    })
})
.catch(console.log)

2. Start your application.

$ node server.js

Edge Server 2 Setup

1. Save the code below as server.js in your server 2 project directory.

const m2m = require('m2m')

// simulated temperature data source
function tempSource(){
  return 20 + Math.floor(Math.random() * 4)
}

let edge = new m2m.Edge()

m2m.connect()
.then(console.log) // success
.then(() => {
    // edge tcp server - private LAN communication
   
    let port = 8126		        // port must be open from your endpoint
    let host = '127.0.0.1' 	        // localhost
    //let host = '192.168.0.115' 	// actual ip of server endpoint
        
    let server = edge.server({port:port, host:host})
    // or
    //let server = edge.createServer(port, host)
    
    // server resources
    server.publish('edge-temperature', (tcp) => {
      let ts = tempSource()
      tcp.polling = 10000	// set polling interval to 10000 ms or 10 secs instead of the default 5000 ms
      tcp.send({port:port, topic:tcp.topic, type:'temperature', value:ts})
    })

    server.get('/update-server-data/:id/new-data/:data', (req, res) => {
      res.send({id:res.id, query:req.query, params:req.params})
    })
  
    server.get('/device-state', (req, res) => {
      res.send({id:res.id, path:res.path, query:req.query, params:req.params, state:'off'})
    })
  
    server.post('/machine-control/:id/actuator/:number/action/:state', (req, res) => {
      res.send({id:res.id, path:res.path, query:req.query, params:req.params})
    })   
})
.catch(console.log)

2. Start your application.

$ node server.js

Edge Client Setup

1. Save the code below as client.js in your client project directory.

const m2m = require('m2m') 

let edge = new m2m.Edge()

m2m.connect()
.then(console.log) // success
.then(() => {
    // edge client 1 
    let ec1 = new edge.client(8125) // localhost
    // or
    //let ec1 = new edge.client({port:8125, ip:'192.168.0.114'}) // actual ip of edge server 1

    ec1.subscribe('edge-voltage', (data) => {
      console.log('edge server 1 edge-voltage', data)
    })

    ec1.read('/machine-1/sensor-1')
    .then(console.log)

    ec1.read('/machine-1/sensor-2')
    .then(console.log)

    ec1.write('/machine-1', {type:'root topic', value:350})
    .then(console.log)

    // unsubscribe
    setTimeout(() => {
      ec1.unsub('edge-voltage')
      .then(result => console.log(result.toString()))
    }, 30000)
})
.then(() => {
  // edge client 2
  let ec2 = new edge.client({port:8126}) // localhost
  // or
  //let ec2 = new edge.client(8126, '192.168.0.115') // actual ip of edge server 2
  
  ec2.subscribe('edge-temperature', (data) => {
    console.log('edge server 2 edge-temperature', data)
  })

  ec2.get('/update-server-data/320/new-data/'+JSON.stringify({pet:'cat', name:'Captain'})+'?name=Rv')
  .then(console.log)
  
  ec2.post('/machine-control/150/actuator/5/action/on?name=Ed', {id:200, state:'true'})
  .then(console.log)

  // unsubscribe
  setTimeout(() => {
    ec2.unsub('edge-temperature')
    .then(result => console.log(result.toString()))
  }, 60000)
})
.catch(console.log)

2. Start your application.

$ node client.js

The expected output should be similar as shown below.

$
success
{ subTopic: '/sensor-1', type: 'sensor-1', value: 168 }
{ subTopic: '/sensor-2', type: 'sensor-2', value: 2 }
{
  rootTopic: '/machine-1',
  subTopic: '',
  type: 'root topic',
  value: 350
}
{
  query: { name: 'Rv' },
  params: { id: '320', data: '{"pet":"cat","name":"Captain"}' }
}
{
  path: '/machine-control/150/actuator/5/action/on?name=Ed',
  query: { name: 'Ed' },
  params: { id: '150', number: '5', state: 'on' }
}
...
edge server 1 edge-voltage { port: 8125, topic: 'edge-voltage', type: 'voltage', value: 59 }
true
...
edge server 2 edge-temperature {
  port: 8126,
  topic: 'edge-temperature',
  type: 'temperature',
  value: 21
}
true