Edge devices communicating through a private local area network

The remote devices must be connected to the internet for authentication ensuring only authorized users can access the edge applications. Users can also configure or edit their edge 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(() => {
  
    let port = 8125		        // must be open if using the endpoint ip
    let host = '127.0.0.1' 	        // using localhost
    //let host = '192.168.0.114' 	// using endpoint ip 
    
    edge.createServer(port, host, (server) => {
    // or   
    //edge.server({port:port, host:host}, (server) => {

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

      // common client read/write resource
      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(() => {
   
    let port = 8126		        // must be open if using the endpoint ip
    let host = '127.0.0.1' 	        // using localhost
    //let host = '192.168.0.115' 	// using endpoint ip
        
    let server = edge.server({port:port, host:host})
    // or
    //let server = edge.createServer(port, host)
    
    // publish resource
    server.pub('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})
    })

    // http get resource
    server.get('/update-server-data/:id/new-data/:data', (req, res) => {
      res.send({id:res.id, query:req.query, params:req.params})
    })

    // http get resource
    server.get('/device-state', (req, res) => {
      res.send({id:res.id, path:res.path, query:req.query, params:req.params, state:'off'})
    })

    // http post resource
    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) // access server using localhost
    // or
    //let ec1 = new edge.client({port:8125, ip:'192.168.0.114'}) // access server using its endpoint ip

    ec1.subscribe('edge-voltage', (data) => {
    // or
    // ec1.sub('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}) 
  // or
  //let ec2 = new edge.client(8126, '192.168.0.115') 
  
  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