Nexus 4 watcher ... email alerts version

n4watcher.js

var email = require('emailjs');
var cheerio = require('cheerio');
var request = require('request');

var url8GB = 'https://play.google.com/store/devices/details?id=nexus_4_8gb';
var url16GB = 'https://play.google.com/store/devices/details?id=nexus_4_16gb';

var defaultState = 'UNKNOWN';
var trackingState8GB = defaultState;
var trackingState16GB = defaultState;
var trackingInterval = 30000;

var soldOut = 'SOLD_OUT';
var cannotMatchRule = 'NO_MATCH';
var commErr = 'COMM_ERR';

var tripBawlsOn = [soldOut, cannotMatchRule];

var emailServer = email.server.connect({
    user: "[email protected]",
    password: "spaceweed",
    host: "smtp.gmail.com",
    ssl: true
});

function emailStateChanged(text, cb) {
    emailServer.send({
        text: text,
        from: "N4 Alerter <[email protected]>",
        to: "your <[email protected]",
        subject: "[N4 WATCHER] : State changed"
    }, cb);

}

function findStatus($, cb) {
    var csElem = $("span.hardware-price-description").first();

    if (csElem.length < 1) {
        return cb(cannotMatchRule);
    } else if (csElem.text().toLowerCase() == "sold out") {
        return cb(soldOut);
    } else {
        return cb(cannotMatchRule);
    }
}

function makeRequest(reqURL, cb) {
    var state = defaultState;
    request(reqURL, function(error, response, body) {
        console.log('Loading ' + reqURL);

        if (!error && response.statusCode == 200) {
            $ = cheerio.load(body);
            findStatus($, function(status) {
                if (status == soldOut) {
                    state = status;
                }
            });
        } else {
            state = commErr;
        }
        cb(state);
    });
}

function track() {
    makeRequest(url8GB, function(currentStatus) {
        if (trackingState8GB != currentStatus) {
            emailStateChanged("ALERT: 8GB Watcher state has changed from " + trackingState8GB + " to " + currentStatus, function(err, message) {
                console.log(err, message);
            });
        }
        trackingState8GB = currentStatus;
        console.log('8GB Status: ' + currentStatus);

    });
    makeRequest(url16GB, function(currentStatus) {
        if (trackingState16GB != currentStatus) {
            emailStateChanged("ALERT: 16GB Watcher state has changed from " + trackingState16GB + " to " + currentStatus, function(err, message) {
                console.log(err, message);
            });
        }
        trackingState16GB = currentStatus;
        console.log('16GB Status: ' + currentStatus);
    });

}

setInterval(function() {
    track();
}, 30000);


track();

Replace the email portions with your own SMTP server, specify whom to send to on line 41.

Install deps:

npm install emailjs cheerio request

Don't forget to setup an inbox rule to flag emails with subject [N4 WATCHER] as prio.

Hopefully some of us will get a N4 before christmas.