Connessione dell'app Web a AWS IoT

Sto usando Raspberry Pi come server web, questa rete serve a controllare la macchina CNC come potete vedere nella figura seguente.

(L'ho preso da Git Hub)

Posso inserire il codice g manualmente o posso caricare il file g codice ma ora voglio collegare questa pagina Web ad Amazon Web Services IoT per inviare automaticamente il codice g alla mia pagina, dopo una lunga ricerca ho trovato questo link che mostra come collegare un'app Web ad AWS IOT, ma penso di aver ancora bisogno di aiuto con queste cose perché non capisco davvero come applicarla. Ecco il file server.js:

var config = require('./config');
var serialport = require("serialport");
var SerialPort = serialport.SerialPort; // localize object constructor
var app = require('http').createServer(handler)
  , io = require('socket.io').listen(app)
  , fs = require('fs');
var static = require('node-static');
var EventEmitter = require('events').EventEmitter;
var url = require('url');
var qs = require('querystring');
var http = require('http');

// test for webcam
config.showWebCam = false;

http.get('http://127.0.0.1:8080', function(res) {
    // valid response, enable webcam
    console.log('enabling webcam');
    config.showWebCam = true;
}).on('socket', function(socket) {
    // 2 second timeout on this socket
    socket.setTimeout(2000);
    socket.on('timeout', function() {
        this.abort();
    });
}).on('error', function(e) {
    console.log('Got error: '+e.message+' not enabling webcam')
});

app.listen(config.webPort);
var fileServer = new static.Server('./i');

function handler (req, res) {

    //console.log(req.url);

    if (req.url.indexOf('/api/uploadGcode') == 0 && req.method == 'POST') {
        // this is a gcode upload, probably from jscut
        console.log('new data from jscut');
        var b = '';
        req.on('data', function (data) {
            b += data;
            if (b.length > 1e6) {
                req.connection.destroy();
            }
        });
        req.on('end', function() {
            var post = qs.parse(b);
            //console.log(post);
            io.sockets.emit('gcodeFromJscut', {'val':post.val});
            res.writeHead(200, {"Content-Type": "application/json"});
            res.end(JSON.stringify({'data':'ok'}));
        });
    } else {
        fileServer.serve(req, res, function (err, result) {
            if (err) console.log('fileServer error: ',err);
        });
    }
}

function ConvChar( str ) {
  c = {'<':'&lt;', '>':'&gt;', '&':'&amp;', '"':'&quot;', "'":'&#039;',
       '#':'&#035;' };
  return str.replace( /[<&>'"#]/g, function(s) { return c[s]; } );
}

var sp = [];
var allPorts = [];

serialport.list(function (err, ports) {

    // if on rPi - http://www.hobbytronics.co.uk/raspberry-pi-serial-port
    if (fs.existsSync('/dev/ttyAMA0') && config.usettyAMA0 == 1) {
        (ports = ports || []).push({comName:'/dev/ttyAMA0',manufacturer: undefined,pnpId: 'raspberryPi__GPIO'});
        console.log('adding /dev/ttyAMA0 because it is enabled in config.js, you may need to enable it in the os - http://www.hobbytronics.co.uk/raspberry-pi-serial-port');
    }

    allPorts = ports;

    for (var i=0; i<ports.length; i++) {
    !function outer(i){

        sp[i] = {};
        sp[i].port = ports[i].comName;
        sp[i].q = [];
        sp[i].qCurrentMax = 0;
        sp[i].lastSerialWrite = [];
        sp[i].lastSerialReadLine = '';
        // 1 means clear to send, 0 means waiting for response
        sp[i].handle = new SerialPort(ports[i].comName, {
            parser: serialport.parsers.readline("\n"),
            baudrate: config.serialBaudRate
        });
        sp[i].sockets = [];

        sp[i].handle.on("open", function() {

            console.log('connected to '+sp[i].port+' at '+config.serialBaudRate);

            // line from serial port
            sp[i].handle.on("data", function (data) {
                serialData(data, i);
            });

            // loop for status ?
            setInterval(function() {
                // console.log('writing ? to serial');
                sp[i].handle.write('?');
            }, 1000);

        });

    }(i)
    }

});

function emitToPortSockets(port, evt, obj) {
    for (var i=0; i<sp[port].sockets.length; i++) {
        sp[port].sockets[i].emit(evt, obj);
    }
}

function serialData(data, port) {

    // handle ?
    if (data.indexOf('<') == 0) {
        // https://github.com/grbl/grbl/wiki/Configuring-Grbl-v0.8#---current-status

        // remove first <
        var t = data.substr(1);

        // remove last >
        t = t.substr(0,t.length-2);

        // split on , and :
        t = t.split(/,|:/);

        emitToPortSockets(port, 'machineStatus', {'status':t[0], 'mpos':[t[2], t[3], t[4]], 'wpos':[t[6], t[7], t[8]]});

        return;
    }

    if (queuePause == 1) {
        // pause queue
        return;
    }

    data = ConvChar(data);

    if (data.indexOf('ok') == 0) {

        // ok is green
        emitToPortSockets(port, 'serialRead', {'line':'<span style="color: green;">RESP: '+data+'</span>'});

        // run another line from the q
        if (sp[port].q.length > 0) {
            // there are remaining lines in the q
            // write one
            sendFirstQ(port);
        }

        // remove first
        sp[port].lastSerialWrite.shift();

    } else if (data.indexOf('error') == 0) {

        // error is red
        emitToPortSockets(port, 'serialRead', {'line':'<span style="color: red;">RESP: '+data+'</span>'});

        // run another line from the q
        if (sp[port].q.length > 0) {
            // there are remaining lines in the q
            // write one
            sendFirstQ(port);
        }

        // remove first
        sp[port].lastSerialWrite.shift();

    } else {
        // other is grey
        emitToPortSockets(port, 'serialRead', {'line':'<span style="color: #888;">RESP: '+data+'</span>'});
    }

    if (sp[port].q.length == 0) {
        // reset max once queue is done
        sp[port].qCurrentMax = 0;
    }

    // update q status
    emitToPortSockets(port, 'qStatus', {'currentLength':sp[port].q.length, 'currentMax':sp[port].qCurrentMax});

    sp[port].lastSerialReadLine = data;

}

var currentSocketPort = {};

function sendFirstQ(port) {

    if (sp[port].q.length < 1) {
        // nothing to send
        return;
    }
    var t = sp[port].q.shift();

    // remove any comments after the command
    tt = t.split(';');
    t = tt[0];
    // trim it because we create the \n
    t = t.trim();
    if (t == '' || t.indexOf(';') == 0) {
        // this is a comment or blank line, go to next
        sendFirstQ(port);
        return;
    }
    //console.log('sending '+t+' ### '+sp[port].q.length+' current q length');

    // loop through all registered port clients
    for (var i=0; i<sp[port].sockets.length; i++) {
        sp[port].sockets[i].emit('serialRead', {'line':'<span style="color: black;">SEND: '+t+'</span>'+"\n"});
    }
    sp[port].handle.write(t+"\n")
    sp[port].lastSerialWrite.push(t);
}

var queuePause = 0;
io.sockets.on('connection', function (socket) {

    socket.emit('ports', allPorts);
    socket.emit('config', config);

    // do soft reset, this has it's own clear and direct function call
    socket.on('doReset', function (data) {
        // soft reset for grbl, send ctrl-x ascii \030
        sp[currentSocketPort[socket.id]].handle.write("\030");
        // reset vars
        sp[currentSocketPort[socket.id]].q = [];
        sp[currentSocketPort[socket.id]].qCurrentMax = 0;
        sp[currentSocketPort[socket.id]].lastSerialWrite = [];
        sp[currentSocketPort[socket.id]].lastSerialRealLine = '';
    });

    // lines from web ui
    socket.on('gcodeLine', function (data) {

        if (typeof currentSocketPort[socket.id] != 'undefined') {

            // valid serial port selected, safe to send
            // split newlines
            var nl = data.line.split("\n");
            // add to queue
            sp[currentSocketPort[socket.id]].q = sp[currentSocketPort[socket.id]].q.concat(nl);
            // add to qCurrentMax
            sp[currentSocketPort[socket.id]].qCurrentMax += nl.length;
            if (sp[currentSocketPort[socket.id]].q.length == nl.length) {
                // there was no previous q so write a line
                sendFirstQ(currentSocketPort[socket.id]);
            }

        } else {
            socket.emit('serverError', 'you must select a serial port');
        }

    });

    socket.on('clearQ', function(data) {
        // clear the command queue
        sp[currentSocketPort[socket.id]].q = [];
        // update the status
        emitToPortSockets(currentSocketPort[socket.id], 'qStatus', {'currentLength':0, 'currentMax':0});
    });

    socket.on('pause', function(data) {
        // pause queue
        if (data == 1) {
            console.log('pausing queue');
            queuePause = 1;
        } else {
            console.log('unpausing queue');
            queuePause = 0;
            sendFirstQ(currentSocketPort[socket.id]);
        }
    });

    socket.on('disconnect', function() {

        if (typeof currentSocketPort[socket.id] != 'undefined') {
            for (var c=0; c<sp[currentSocketPort[socket.id]].sockets.length; c++) {
                if (sp[currentSocketPort[socket.id]].sockets[c].id == socket.id) {
                    // remove old
                    sp[currentSocketPort[socket.id]].sockets.splice(c,1);
                }
            }
        }

    });

    socket.on('usePort', function (data) {

        console.log('user wants to use port '+data);
        console.log('switching from '+currentSocketPort[socket.id]);

        if (typeof currentSocketPort[socket.id] != 'undefined') {
            for (var c=0; c<sp[currentSocketPort[socket.id]].sockets.length; c++) {
                if (sp[currentSocketPort[socket.id]].sockets[c].id == socket.id) {
                    // remove old
                    sp[currentSocketPort[socket.id]].sockets.splice(c,1);
                }
            }
        }

        if (typeof sp[data] != 'undefined') {
            currentSocketPort[socket.id] = data;
            sp[data].sockets.push(socket);
        } else {
            socket.emit('serverError', 'that serial port does not exist');
        }

    });

});

Ciò che hai collegato è fin troppo complicato e con un livello di astrazione troppo basso che per un professionista è persino difficile leggerlo e seguirlo.

aws-mqtt-client tramite npm è la soluzione più semplice che ho trovato. Devi solo installare npm e rendere il servizio aws e il codice client è abbastanza semplice:

const mqttClient = new AWSMqtt({
    accessKeyId: AWS_ACCESS_KEY,
    secretAccessKey: AWS_SECRET_ACCESS_KEY,
    sessionToken: AWS_SESSION_TOKEN,
    endpointAddress: AWS_IOT_ENDPOINT_HOST,
    region: 'us-east-1'
});

Inserisci i valori corretti lì e pubblica i dati dal tuo computer in questo modo:

mqttClient.publish(MQTT_TOPIC, message);

E sul sito che necessita dei dati, li ottieni:

mqttClient.on('connect', () => {
    mqttClient.subscribe('test-topic');
    console.log('connected to iot mqtt websocket');
});
mqttClient.on('message', (topic, message) => {
    console.log(message.toString());
});

Ulteriori informazioni:

https://www.npmjs.com/package/aws-mqtt-client

https://www.npmjs.com/get-npm

https://aws.amazon.com/iot-platform/getting-started/