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aws-iot-with-nodejs
"use strict";
var mqtt = require('mqtt');
var fs = require('fs');
var Path = require('path');
var express = require('express');
var app = express();
var http = require('http').Server(app);
var io = require('socket.io')(http);
var co = require('co');
var wrapRoute = require('co-express');
var exphbs = require('express-handlebars');
var AWS = require('aws-sdk');
var promisify = require('es6-promisify');
// Configure AWS
var iam = require('../icebreaker-cert/iam.js'); // contains uname/pwd for dynamodb
iam.endpoint = 'https://dynamodb.us-east-1.amazonaws.com';
AWS.config.update(iam);
var dynamodbDoc = new AWS.DynamoDB.DocumentClient();
// End configure AWS
var hbs = exphbs.create({ extname: '.html' });
app.engine('html', hbs.engine);
app.set('view engine', 'html');
app.use(express.static('public'));
app.get('/', (req, res) => res.render('index'));
app.get('/api/:stuff/:thing/history', wrapRoute(function*(req, res, next) {
res.send(yield getHistory(req.params.stuff, req.params.thing, req.query.limit || 500,
(Date.now() - (1000 * 60 * 60 * 24 * 7))));
}));
function*getHistory(stuff, thing, limit, ts) {
let params = {
TableName: 'LoRaData',
KeyConditionExpression: 'topic = :topic AND #ts > :ts',
ExpressionAttributeNames: {
'#ts': 'timestamp'
},
Limit: limit,
ExpressionAttributeValues: {
':topic': stuff + '/' + thing,
':ts': ts.toString()
},
ScanIndexForward: false
};
try {
let data = yield promisify(dynamodbDoc.query.bind(dynamodbDoc))(params);
return data.Items.map(it => {
delete it.topic;
it.timestamp = Number(it.timestamp);
return it;
});
}
catch (ex) {
throw 'Unable to query DynamoDB. Error: ' + JSON.stringify(ex, null, 2);
}
}
// MQTT
var mqttOpts = {
topic: 'lora/#',
key: fs.readFileSync(Path.join(__dirname, '../icebreaker-cert/4deb112637-private.pem.key')),
cert: fs.readFileSync(Path.join(__dirname, '../icebreaker-cert/4deb112637-certificate.pem.crt')),
ca: fs.readFileSync(Path.join(__dirname, '../icebreaker-cert/rootCA.pem')),
protocol: 'mqtts',
hostname: 'A3RCG9B7I2IJYK.iot.us-east-1.amazonaws.com',
port: 8883
};
var mqttClient = mqtt.connect(mqttOpts);
mqttClient.on('connect', () => {
console.log('Connected over MQTT');
mqttClient.subscribe(mqttOpts.topic, { qos: 0 });
});
mqttClient.on('message', (topic, payload) => {
// console.log('got message', topic, payload);
try {
io.to('topic:' + topic).emit('message', JSON.parse(payload.toString()));
}
catch (ex) {
console.error('Failed to parse message', topic, payload);
}
});
io.on('connection', socket => {
socket.on('subscribe', topic => {
console.log('subscribe to topic:' + topic);
socket.join('topic:' + topic);
});
});
var server = http.listen(process.env.PORT || 6173, () => {
var host = server.address().address;
var port = server.address().port;
console.log('Listening at http://%s:%s', host, port);
});
@janjongboom
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janjongboom commented Oct 15, 2015

Run:

npm install mqtt express socket.io co co-express express-handlebars aws-sdk es6-promisify

first

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