Example client for the Yanzi Cirrus API

yanzi_api_example.js

const WebSocket = require('ws');
const http = require('http');

function assertDefinedEnv(varname) {
        if (!(varname in process.env))
                throw "Error: Missing required env var " + varname;
}

assertDefinedEnv("SHREK_URL");
assertDefinedEnv("PLUG_ENERGY_DID");
assertDefinedEnv("PLUG_GPIO_DID");
assertDefinedEnv("SENSOR_LID");
assertDefinedEnv("YANZI_USER");
assertDefinedEnv("YANZI_PASS");
process.env.NODE_TLS_REJECT_UNAUTHORIZED = '0';

const PORT = process.env.PORT || 5000;

let cirrus_ws = new WebSocket(process.env.SHREK_URL, {
        origin: 'https://devshrek.yanzi.se'
});

//For this simple example, lets just store the last value in a global var.
var global_last_known_usage = -1;

/**
 * Send an object over the cirrus connection. This will fail if the websocket
 * is not open.
 */
function sendMessage(message) {
        if (cirrus_ws.readyState != WebSocket.OPEN) {
                console.error("Couldn't send cirrus message: Socket not open");
                return;
        }

        try {
                cirrus_ws.send(JSON.stringify(message, null, 1));
        } catch (e) {
                console.error("Couldn't send cirrus message. " + e);
        }
}


function sendLoginRequest(username, password) {
        var request = {
                "messageType": "LoginRequest",
                "username": username,
                "password": password,
                "timeSent": new Date().getTime()
        }
        sendMessage(request);
}


function subscribeToDataFromLocation(locationId) {
        var request = {
                "messageType": "SubscribeRequest",
                "timeSent": new Date().getTime(),
                "unitAddress": {
                        "resourceType": "UnitAddress",
                        "locationId": locationId
                },
                "subscriptionType": {
                        "resourceType": "SubscriptionType",
                        "name": "data"
                }
        }
        sendMessage(request);
}


/**
 * Really simple method to extract a single instantPower from a SubscribeData
 * response for the specified lid/did. Will return undefined if not found.
 * */
function extractPlugUsageFromSubscribeData(json, lid, did) {
        for (var i in json.list) {
                var sample_list = json.list[i];

                //Is this our sensor?
                if (sample_list.dataSourceAddress.did == did) {
                        console.log("Got update from plug")
                        console.log(JSON.stringify(sample_list.list[0]))

                        if (sample_list.list.length == 0)
                                throw "Error: empty sample list";

                        return sample_list.list[0].instantPower;
                }
        }
        return undefined;
}


function processResponse(json) {

        if (json.messageType == "LoginResponse") {
                console.log("Got login status: " + json.responseCode.name);
                // lets assume we were logged in
                subscribeToDataFromLocation(process.env.SENSOR_LID);

        } else if (json.messageType == "SubscribeData") {

                var res = extractPlugUsageFromSubscribeData(json, process.env.SENSOR_LID, process.env.PLUG_ENERGY_DID);
                if (res !== undefined) {
                        global_last_known_usage = res;
                }
        }
}



/**
 * Send a message to do a binary turn-off of the specified unit.
 */
function sendTurnOff(lid, did) {
        var request = {
                "messageType": "ControlRequest",
                "timeSent": new Date().getTime(),
                "unitAddress": {
                        "resourceType": "UnitAddress",
                        "did": did,
                        "locationId": lid
                },
                "did": did,
                "controlValue": {
                        "resourceType": "ControlValueBinary",
                        "value": false
                }
        };

        sendMessage(request);
}

function sendTurnOn(lid, did) {
        var request = {
                "messageType": "ControlRequest",
                "timeSent": new Date().getTime(),
                "unitAddress": {
                        "resourceType": "UnitAddress",
                        "did": did,
                        "locationId": lid
                },
                "did": did,
                "controlValue": {
                        "resourceType": "ControlValueBinary",
                        "value": true
                }
        };

        sendMessage(request);
}

/**
 * Event handlers for websocket:
 */
cirrus_ws.on('connection', function connection(ws, req) {
        console.log(JSON.stringify(req));
        const ip = req.connection.remoteAddress;
});

cirrus_ws.on('open', function open() {
        console.log("Connection opened");

        // Lets log in immidiately
        sendLoginRequest(process.env.YANZI_USER, process.env.YANZI_PASS);
});


cirrus_ws.on('message', function (data, flags) {
        processResponse(JSON.parse(data));
});

function handleRequest(request, response) {
        response.write("<html>");

        if (request.url == "/off") {
                sendTurnOff(process.env.SENSOR_LID, process.env.PLUG_GPIO_DID);
                response.write("Sent turn-off command");
        }

        if (request.url == "/on") {
                sendTurnOn(process.env.SENSOR_LID, process.env.PLUG_GPIO_DID);
                response.write("Sent turn-on command");
        }

        if (global_last_known_usage == -1) {
                response.write("Waiting for information about the plug");
        } else {
                response.write('The plug is using '
                        + (global_last_known_usage > 2 ? global_last_known_usage + " W" : "0 W"));
        }
        response.write("<br><a href=/on>Send turn-on command</a>")
        response.end("<br><a href=/off>Send turn-off command</a></html>");
}

var server = http.createServer(handleRequest);

//Lets start our server
server.listen(PORT, function () {
        console.log("Server listening on: http://localhost:%s", PORT);
});