npm install race condition

Description

When using hap-nodejs via npm I discovered that it actually mattered in what order the packages hap-nodejs and node-persist@0.0.8 are installed.

When I initially attempted to use this library, I looked at the BridgedCore.js example. Then I installed the needed packages and tried to refactor the code, so that it uses the npm dependencies.

I encountered a lot of problems related to localStorage being undefined. This is because of a hack, this library relies on. It trusts node-persist to be the same instance on the library & BridgedCore.js files. However, when you install hap-nodejs first, npm will install two instances of node-persist, which breaks the localStorage.

Case Distinction

a) install hap-nodejs first

This reliably fails on both of my systems, since npm will install two instances of node-persist.

Console Output

HAP-NodeJS starting...
/home/dodekeract/code/HAP-NodeJS/node_modules/hap-nodejs/node_modules/node-persist/node-persist.js:107
        return localStorage.getItem(key, callback);
                           ^

TypeError: Cannot read property 'getItem' of undefined
    at Object.nodePersist.getItem (/home/dodekeract/code/HAP-NodeJS/node_modules/hap-nodejs/node_modules/node-persist/node-persist.js:107:28)
    at Function.AccessoryInfo.load (/home/dodekeract/code/HAP-NodeJS/node_modules/hap-nodejs/lib/model/AccessoryInfo.js:103:23)
    at Bridge.Accessory.publish (/home/dodekeract/code/HAP-NodeJS/node_modules/hap-nodejs/lib/Accessory.js:417:39)
    at Object.<anonymous> (/home/dodekeract/code/HAP-NodeJS/BridgedCore.js:25:8)
    at Module._compile (module.js:409:26)
    at Object.Module._extensions..js (module.js:416:10)
    at Module.load (module.js:343:32)
    at Function.Module._load (module.js:300:12)
    at Function.Module.runMain (module.js:441:10)
    at startup (node.js:139:18)

npm list

hap-nodejs-bug@1.0.0 /home/dodekeract/code/HAP-NodeJS
├─┬ hap-nodejs@0.3.2
│ ├─┬ curve25519@1.1.0 (git://github.com/KhaosT/node-curve25519.git#922eae612bb379fa84e8deb29f80c53d57c8be7b)
│ │ ├── bindings@1.2.1
│ │ └── nan@2.3.2
│ ├─┬ debug@2.2.0
│ │ └── ms@0.7.1
│ ├─┬ ed25519@0.0.3 (git://github.com/KhaosT/ed25519.git#6356bc9e6e4643d56020293c14920ac12bcaa1ac)
│ │ ├── bindings@1.2.1
│ │ └── nan@2.3.2
│ ├─┬ mdns@2.3.2
│ │ ├── bindings@1.2.1
│ │ └── nan@2.2.1
│ ├─┬ node-persist@0.0.8
│ │ ├── mkdirp@0.3.5
│ │ └── q@1.1.2
│ └─┬ srp@0.2.0 (git://github.com/KhaosT/node-srp.git#7feff53254897a0b1b9f0667ad17a8beb78acbb9)
│   └─┬ bignum@0.11.0
│     └── nan@2.3.2
└─┬ node-persist@0.0.8
  ├── mkdirp@0.3.5
  └── q@1.1.2

Two separate instances of node-persist.

b) install node-persist@0.0.8 first

This fixed the issue, since only one instance of node-persist will be installed. Took me about 4 hours to figure this one out though.

Console Output

HAP-NodeJS starting...

npm list

hap-nodejs-bug@1.0.0 /home/dodekeract/code/HAP-NodeJS
├─┬ hap-nodejs@0.3.2
│ ├─┬ curve25519@1.1.0 (git://github.com/KhaosT/node-curve25519.git#922eae612bb379fa84e8deb29f80c53d57c8be7b)
│ │ ├── bindings@1.2.1
│ │ └── nan@2.3.2
│ ├─┬ debug@2.2.0
│ │ └── ms@0.7.1
│ ├─┬ ed25519@0.0.3 (git://github.com/KhaosT/ed25519.git#6356bc9e6e4643d56020293c14920ac12bcaa1ac)
│ │ ├── bindings@1.2.1
│ │ └── nan@2.3.2
│ ├─┬ mdns@2.3.2
│ │ ├── bindings@1.2.1
│ │ └── nan@2.2.1
│ └─┬ srp@0.2.0 (git://github.com/KhaosT/node-srp.git#7feff53254897a0b1b9f0667ad17a8beb78acbb9)
│   └─┬ bignum@0.11.0
│     └── nan@2.3.2
└─┬ node-persist@0.0.8
  ├── mkdirp@0.3.5
  └── q@1.1.2

As you can see, there is only one instance of node-persist.

Code To Reproduce This

BridgedCore.js (modified)

var path = require('path');
var storage = require('node-persist');
var uuid = require('hap-nodejs').uuid;
var Bridge = require('hap-nodejs').Bridge;
var Accessory = require('hap-nodejs').Accessory;

console.log("HAP-NodeJS starting...");

// Initialize our storage system
storage.initSync();

// Start by creating our Bridge which will host all loaded Accessories
var bridge = new Bridge('Node Bridge', uuid.generate("Node Bridge"));

// Listen for bridge identification event
bridge.on('identify', function(paired, callback) {
  console.log("Node Bridge identify");
  callback(); // success
});

bridge.addBridgedAccessory(require('./Light_accessory.js').accessory);

// Publish the Bridge on the local network.
bridge.publish({
  username: "CC:22:3D:E3:CE:F6",
  port: 51826,
  pincode: "031-45-154",
  category: Accessory.Categories.BRIDGE
});

Light_accessory.js (modified)

var Accessory = require('hap-nodejs').Accessory;
var Service = require('hap-nodejs').Service;
var Characteristic = require('hap-nodejs').Characteristic;
var uuid = require('hap-nodejs').uuid;

// here's a fake hardware device that we'll expose to HomeKit
var FAKE_LIGHT = {
  powerOn: false,
  brightness: 100, // percentage

  setPowerOn: function(on) {
    console.log("Turning the light %s!", on ? "on" : "off");
    FAKE_LIGHT.powerOn = on;
  },
  setBrightness: function(brightness) {
    console.log("Setting light brightness to %s", brightness);
    FAKE_LIGHT.brightness = brightness;
  },
  identify: function() {
    console.log("Identify the light!");
  }
}

// Generate a consistent UUID for our light Accessory that will remain the same even when
// restarting our server. We use the `uuid.generate` helper function to create a deterministic
// UUID based on an arbitrary "namespace" and the word "light".
var lightUUID = uuid.generate('hap-nodejs:accessories:light');

// This is the Accessory that we'll return to HAP-NodeJS that represents our fake light.
var light = exports.accessory = new Accessory('Light', lightUUID);

// Add properties for publishing (in case we're using Core.js and not BridgedCore.js)
light.username = "1A:2B:3C:4D:5E:FF";
light.pincode = "031-45-154";

// set some basic properties (these values are arbitrary and setting them is optional)
light
  .getService(Service.AccessoryInformation)
  .setCharacteristic(Characteristic.Manufacturer, "Oltica")
  .setCharacteristic(Characteristic.Model, "Rev-1")
  .setCharacteristic(Characteristic.SerialNumber, "A1S2NASF88EW");

// listen for the "identify" event for this Accessory
light.on('identify', function(paired, callback) {
  FAKE_LIGHT.identify();
  callback(); // success
});

// Add the actual Lightbulb Service and listen for change events from iOS.
// We can see the complete list of Services and Characteristics in `lib/gen/HomeKitTypes.js`
light
  .addService(Service.Lightbulb, "Fake Light") // services exposed to the user should have "names" like "Fake Light" for us
  .getCharacteristic(Characteristic.On)
  .on('set', function(value, callback) {
    FAKE_LIGHT.setPowerOn(value);
    callback(); // Our fake Light is synchronous - this value has been successfully set
  });

// We want to intercept requests for our current power state so we can query the hardware itself instead of
// allowing HAP-NodeJS to return the cached Characteristic.value.
light
  .getService(Service.Lightbulb)
  .getCharacteristic(Characteristic.On)
  .on('get', function(callback) {

    // this event is emitted when you ask Siri directly whether your light is on or not. you might query
    // the light hardware itself to find this out, then call the callback. But if you take longer than a
    // few seconds to respond, Siri will give up.

    var err = null; // in case there were any problems

    if (FAKE_LIGHT.powerOn) {
      console.log("Are we on? Yes.");
      callback(err, true);
    }
    else {
      console.log("Are we on? No.");
      callback(err, false);
    }
  });

// also add an "optional" Characteristic for Brightness
light
  .getService(Service.Lightbulb)
  .addCharacteristic(Characteristic.Brightness)
  .on('get', function(callback) {
    callback(null, FAKE_LIGHT.brightness);
  })
  .on('set', function(value, callback) {
    FAKE_LIGHT.setBrightness(value);
    callback();
  })

Proposed Solution

Since relying on only having one instance of node-persist is apparently error-prone, I suggest to just allow users to pass in any storage solution they want to pass into this library. At least allow passing an instance of node-persist to have a reliable way to fix this issue.

Versions

npm: 2.15.1 node: 4.4.3 hap-nodejs: 0.3.2 node-persist: 0.0.8 OS: Ubuntu 16.04 & Raspbian Jessie

[underbluewaters]

Okay, found a solution to the problem with node-persist initialization. For me at least. I was able to call the init method exposed by the main hap-nodejs module and that solved the issue. So in my code, it looks like this:

// no need for this
// const storage = require('node-persist');
// storage.initSync();
const HAP = require('hap-nodejs');
HAP.init();

[KhaosT]

@dodekeract and if you want, here is the sample test I created trying to reproduce this problem. After npm install it runs fine.