demo.gyro.js

// http://ejohn.org/blog/ecmascript-5-strict-mode-json-and-more/
"use strict";

/*
 * WebSocket server for the L3GD20 gyroscope
 * WebSocket doc at https://www.npmjs.com/package/websocket
 * Static requests must be prefixed with /data/, like in http://machine:9876/data/demos/gyro.one.html
 */
process.title = 'node-gyro'; // Optional. You will see this name in eg. 'ps' or 'top' command

// Port where we'll run the websocket server
let port = 9876;

// websocket and http servers
let webSocketServer = require('websocket').server;
let http = require('http');
let fs = require('fs');

let verbose = false;

if (typeof String.prototype.startsWith !== 'function') {
    String.prototype.startsWith = function (str) {
        return this.indexOf(str) === 0;
    };
}

if (typeof String.prototype.endsWith !== 'function') {
    String.prototype.endsWith = function (suffix) {
        return this.indexOf(suffix, this.length - suffix.length) !== -1;
    };
}

// HTTP Handler
let handler = (req, res) => {
    let respContent = "";
    if (verbose === true) {
        console.log("Speaking HTTP from " + __dirname);
        console.log("Server received an HTTP Request:\n" + req.method + "\n" + req.url + "\n-------------");
        console.log("ReqHeaders:" + JSON.stringify(req.headers, null, '\t'));
        console.log('Request:' + req.url);
        let prms = require('url').parse(req.url, true);
        console.log(prms);
        console.log("Search: [" + prms.search + "]");
        console.log("-------------------------------");
    }
    if (req.url.startsWith("/data/")) { // Static resource
        let resource = req.url.substring("/data/".length);
        if (resource.indexOf("?") > -1) {
            resource = resource.substring(0, resource.indexOf("?"));
        }
        console.log('Loading static ' + req.url + " (" + resource + ")");
        fs.readFile(__dirname + '/' + resource,
            function (err, data) {
                if (err) {
                    res.writeHead(500);
                    return res.end('Error loading ' + resource);
                }
                // if (verbose)
                //   console.log("Read resource content:\n---------------\n" + data + "\n--------------");
                let contentType = "text/html";
                if (resource.endsWith(".css"))
                    contentType = "text/css";
                else if (resource.endsWith(".html"))
                    contentType = "text/html";
                else if (resource.endsWith(".xml"))
                    contentType = "text/xml";
                else if (resource.endsWith(".js"))
                    contentType = "text/javascript";
                else if (resource.endsWith(".jpg"))
                    contentType = "image/jpg";
                else if (resource.endsWith(".gif"))
                    contentType = "image/gif";
                else if (resource.endsWith(".png"))
                    contentType = "image/png";
                else if (resource.endsWith(".ico"))
                    contentType = "image/ico";

                res.writeHead(200, {'Content-Type': contentType});
                if (resource.endsWith(".jpg") ||
                    resource.endsWith(".gif") ||
                    resource.endsWith(".ico") ||
                    resource.endsWith(".png")) {
                    //  res.writeHead(200, {'Content-Type': 'image/gif' });
                    res.end(data, 'binary');
                } else
                    res.end(data.toString().replace('$PORT$', port.toString())); // Replace $PORT$ with the actual port value.
            });
    } else if (req.url == "/") {
        if (req.method === "POST") {
            let data = "";
            console.log("---- Headers ----");
            for (let item in req.headers)
                console.log(item + ": " + req.headers[item]);
            console.log("-----------------");

            req.on("data", function (chunk) {
                data += chunk;
            });

            req.on("end", function () {
                console.log("POST request: [" + data + "]");
                res.writeHead(200, {'Content-Type': 'application/json'});
                let status = {'status': 'OK'};
                res.end(JSON.stringify(status));
            });
        }
    } else {
        console.log("Un-managed request: [" + req.url + "]");
        respContent = "Response from " + req.url;
        res.writeHead(404, {'Content-Type': 'text/plain'});
        res.end(); // respContent);
    }
}; // HTTP Handler

let clients = []; // list of currently connected clients

/**
 * HTTP server
 */
let server = http.createServer(handler);
server.listen(port, () => {
    console.log((new Date()) + " Server is listening on port " + port);
    console.log("Connect to [http://localhost:9876/data/demos/gyro.one.html]");
});

/**
 * WebSocket server
 */
let wsServer = new webSocketServer({
    // WebSocket server is tied to a HTTP server. WebSocket request is just
    // an enhanced HTTP request. For more info http://tools.ietf.org/html/rfc6455#page-6
    httpServer: server
});

// This callback function is called every time someone
// tries to connect to the WebSocket server
wsServer.on('request', (request) => {
    console.log((new Date()) + ' Connection from origin ' + request.origin + '.');

    // accept connection - you should check 'request.origin' to make sure that
    // client is connecting from your website
    // (http://en.wikipedia.org/wiki/Same_origin_policy)
    let connection = request.accept(null, request.origin);
    clients.push(connection);
    console.log((new Date()) + ' Connection accepted.');

    // user sent some message
    connection.on('message', (message) => {
        if (message.type === 'utf8') { // accept only text
            for (let i = 0; i < clients.length; i++) {
                clients[i].sendUTF(message.utf8Data);
            }
        }
    });

    // user disconnected
    connection.on('close', (code) => {
        // Close
        console.log((new Date()) + ' Connection closed.');
        let nb = clients.length;
        for (let i = 0; i < clients.length; i++) {
            if (clients[i] === connection) {
                clients.splice(i, 1);
                break;
            }
        }
        if (verbose) {
            console.log("We have (" + nb + "->) " + clients.length + " client(s) connected.");
        }
    });
});

// Called by the gyroscope (below)
let broadcastGyroData = (x, y, z) => {
    let mess = {x: x, y: y, z: z};
    for (let i = 0; i < clients.length; i++) {
        clients[i].sendUTF(JSON.stringify(mess));
    }
};

// Gyro Sensor part
let L3GD20 = require('./l3gd20.js').L3GD20;
let L3GD20Dictionaries = require('./utils/L3GD20Dictionaries.js').L3GD20Dictionaries;

let l3gd20 = new L3GD20();

console.log("Init...")
try {
    l3gd20.open();
    l3gd20.setPowerMode(L3GD20Dictionaries.NORMAL);
    l3gd20.setFullScaleValue(L3GD20Dictionaries._250_DPS);
    l3gd20.setAxisXEnabled(true);
    l3gd20.setAxisYEnabled(true);
    l3gd20.setAxisZEnabled(true);
} catch (err) {
    console.log(err);
    process.exit();
}
console.log("Starting...");
l3gd20.init();
l3gd20.calibrate();

let prevX, prevY, prevZ;

let minX = 0, maxX = 0, minY = 0, maxY = 0, minZ = 0, maxZ = 0;

let iv = setInterval(() => {
    let data = l3gd20.getCalOutValue();
    let x = data[0], y = data[1], z = data[2];
    if (x !== prevX || y !== prevY || z !== prevZ) {
        broadcastGyroData(x, y, z); // Invoke the client
    }
    minX = Math.min(x, minX);
    maxX = Math.max(x, maxX);
    minY = Math.min(y, minY);
    maxY = Math.max(y, maxY);
    minZ = Math.min(z, minZ);
    maxZ = Math.max(z, maxZ);
    prevX = x;
    prevY = y;
    prevZ = z;
}, 20);

// cleanup on exit
let exit = () => {
    console.log("Bye!");
    l3gd20.shutdown();
    console.log("x in [" + minX + ", " + maxX +
        "], y in [" + minY + ", " + maxY +
        "], z in [" + minZ + ", " + maxZ + "]");
    process.exit();
};
process.on('SIGINT', exit); // Ctrl C