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The Smart(er) Machine-Learned IoT Cat Feeder for Lola the Cat – Part 1

tl;dr – I modified my cat feeder to only feed one of my two cats using a Raspberry Pi webcam and image analysis with TensorFlow.

Meet Lola

Lola Resting

My cat for seven years who is healthy and fuzzy and an all-around good cat. However, she is a very picky eater. She takes small bites of food sporadically throughout the day from a food dish just for her on top of a tall dresser.

Meet Madison (Maddie for short)

Hi Maddie

Obese cat that was recently put on a strict diet of canned food twice a day (no carbs!). Due to her obesity, she’s been unable to leap onto the dresser to eat Lola’s food. Until now. Perhaps she’s regaining some athletic ability with the new diet, or her appetite has overwhelmed her fear, but a couple weeks ago she finally made the leap to the bounty of Lola’s food dish. Not good.

The Problem

Lola likes her dry food (a mix of Science Diet and Orijen), and only eats a tiny bit at a time whenever she wants. I’ve made several attempts at getting her on a schedule, but this results in incessant yowling at all hours along with a stubborn refusal to eat during the allotted mealtime. All was well when Lola was the only cat with the leaping ability to reach the skyward food dish. Now there’s no place for cat food to hide that Maddie won’t find.

I needed a way to keep Maddie on her diet, but allow Lola to peck at her food when she decides it’s mealtime. If tiny portions of food could be presented to Lola, she would eat all of it leaving none for Maddie. But how to get Lola (and not Maddie) tiny portions of food when I’m away at work or sleeping?

The Feeder

CSF Super Feeder

I bought an automated cat feeder a few years ago to dispense food to the cats whilst on vacation. It’s sturdy, but very primitive compared to today’s IoT designs. It works by plugging into a wall timer, and dispensing food for a short duration when AC current is supplied, and then resets when the power is cut. The amount of food dispensed is determined by twisting a small potentiometer with a tiny screwdriver (seriously!).

If the Feeder Only Had A Brain

I have a cursory fascination with machine learning, and sometimes read about what’s what in the ML world. TensorFlow has been a hot topic of late, and they have a few dead simple tutorials for lay people like myself. TensorFlow For Poets shows how to retrain an image labelling model to recognize objects of your choosing… like perhaps your own pets.

I thought maybe, just maybe, I could fiddle with the TensorFlow tutorial’s code and cobble together a system that allows the feeder to ‘recognize’ Lola and dispense a tiny meal for her, but refuse service to Maddie. Given the simple nature of the feeder (plug in = food, unplug = reset), some sort of smart-plug for the feeder would work just fine.

The Bright Idea

Grinch Smirk

I have a couple Raspberry Pis lying around (what self-respecting tech nerd doesn’t?), and decided to use one for the guts of the operation. The full solution looked something like this…

Set up the RPi + camera to watch for cats mulling about near the feeder. Periodically snap a photo, and analyze said photo with TensorFlow to find Lola. If Lola is identified in the image, flip the switch on a smart plug or relay connected to feeder with the RPi. Then shut off the power to the feeder and sleep for an hour or two before allowing another feeding. We don’t want it constantly spitting out food while Lola is eating.

The Working Contraption

feeder1

After a few days of tinkering, trial and error, ordering bits and bobs from the internet, and convincing my wife that I’m not crazy, I finally got a working version! As I suspected from the outset, it’s very much cobbled together and has a few quirks, but it does what I set out for it to do – feed one cat, but not the other.

(Quick reminder, I do still feed Maddie, but only twice a day with incredibly expensive cat food that I swear is better than what I eat some days)

The parts list for the working prototype are as follows…

The software involved includes…

  • Raspbian OS
  • TensorFlow
  • Python (and Flask)
  • Node.js
  • ffmpeg
  • IFTTT/Twitter/Twilio account (optional)

The “How it Works”

The RPi is set up near the feeder in a small box. The camera is pointing to the area in front of the feeder. After turning on the feeder, a python script bootstraps TensorFlow which loads the trained model into memory and gets ready to analyze an image. It waits until it is triggered by a GET request set up with Flask. So TensorFlow twiddles its thumbs, waiting patiently for some work to do.

Concurrently, A Node script fires up to do the ‘detection and feeder’ cycle. The script goes a little something like this…

A picture is taken with the camera. After the photo is saved to disk, the Node app calls the python service which analyzes the image and returns some JSON data. The data includes the probabilities of Lola and Maddie being in the image. If the “Lola probability” is greater than 99.3%, the Node script sends an RF signal to turn on the outlet with the connected feeder plug. The feeder gets power and dispenses a tiny bit of food. After a few seconds, the Node script sends an RF signal to turn off the feeder, then sends a message to IFTTT to alert me that Lola got food. It also copies the last image taken into another folder and timestamps the filename. The cycle then times out for 90 minutes, and then resumes taking pictures.

It all works surprisingly well, except at night when the camera sees only blackness. Luckily, the RF controlled outlets come in packs of five, so I hooked up a lamp to another one and have the Node script also turn the light on for a couple hours in the evening, and early in the morning (Lola really likes to eat at 5:30am, and she lets us know it).

The IFTTT notification and copied image are nice-to-haves that let me keep an eye on things until I get a better interface put together. It also lets me check out any false positives that might occur, and give me better ideas for retraining the TensorFlow model.

On the TODO List

  • Definitely a sturdier box and camera mount. Lola has already threatened to knock the whole thing off the desk (as cats do), and barely a tap will knock the camera out of place.
  • A PIR motion detector to trigger the camera instead of running the camera non-stop. Not sure how useful it would be, but I have a PIR sensor, so why not?
  • A database to record data. Collect feeding times and pictures to get a better idea of Lola’s eating habits.
  • A web interface. It would be nice to adjust the timeout between feedings, manually trigger a feeding, control the lamp, and generally see what’s going on via the web.
  • A Maddie scarecrow. Sometimes Lola does’t quite eat all the food, and Maddie jumps in behind her to finish the job. Might be worthwhile to play a loud noise or something if Maddie is detected (but not Lola) soon after a feeding occurs.
  • 100% Python. I used Node because I know Node, but there’s no reason this couldn’t be one Python script instead of two separate programs. Someday I’ll fulfill my dream of learning Python, and may refactor this project accordingly.

Stay Tuned

More posts will follow on the technical details of the implementation. TTFN!

A Phaser 2.0 Game: Welcome Back Alex

welcom_back_alex

As Christmas 2014 approached I was faced with the yearly conundrum of what to gift to my various loved ones. I think I did an adequate job selecting items for most people, but I wanted to get my brother something good since he’s been out of the country for two years teaching English in Korea.

I saw this as a good opportunity to finally try out the Phaser framework that I’ve been following for quite some time, but never really used. Phaser is a game-making library written in JavaScript that provides a ton of great utilities for making 2D games that work on the web.

Phaser.io Given that Christmas was my deadline, and I started in mid-November, I had to be pretty modest in my expectations. Learning a new framework, and coding everything by hand (as opposed to using graphical tools like Construct 2 or Unity) further exacerbated the time constraints. Luckily, with the help of several online examples and some darn good official documentation, I was able to squeek out something the kind-of passes as a “game” and provided a few hearty minutes of entertainment on Christmas day.

The game itself follows my brother, Alex, on his journey home from Korea. In level one, Alex must protect the school-children from the invading Zerglings. In real life, Alex spent a few months bumming around the South Pacific backpacking through jungles and across beaches. So in level two, the objective is to cross the beach, avoiding obstacles and find the lovely lady. Finally, Alex reaches home (Wisconsin) and decides to take our parent’s new dog, Sophie, for a walk – in the middle of the street! Avoid the cars and win the game!

The source code is available on Github, and I can’t promise that it’s great. The modules are haphazardly written and there’s definitely some copy-pasta going on in a few places, but I tried to take as many queues from the official docs as possible in regards to best practices. Follow the links below to play the game, or view the code.

Play the game!

Grab the source code!

JavaScript Powered Stuff

CODE | SLIDES

What Did I Just Watch in That Video?

That video was the culmination of me experimenting with a Spark Core device, the Johnny Five library, a Sphero toy, and the Cylon.js library (along with some other JavaScripty stuff).

Here’s what is really going on in the video…

My computer is running a Node.JS application of my own creation called owLED (available on GitHub).

Connected to my computer is a Spark Core device (basically a wireless Arduino). Attached to the Spark Core are 2 LED lights – one red, one greenish-white – and a pushbutton, all connected with some wires via a breadboard. See the amateurish image below for something that resembles what I put together.

owLED_bb

The owLED Node.JS application does a few things…

1. Serves a page with a picture of an owl at http://localhost:3000
2. Creates a Socket.IO connection between the browser and the Node app
3. Loads a Johnny-Five module that blinks the LED lights when the button is pushed, then emits an event when the blinking is complete (along with the on/off status of each LED).
4. Loads a Cylon.js module to connect to Sphero. The module exposes a function to change Sphero’s color, and roll Sphero ‘forward’ a short distance.

With all these pieces working in concert, we have a (crappy) little game! When I push the button on the Spark Core, the LED lights blink randomly for a couple seconds then stop. The LEDs can be either on or off when the blinking sequence ends.

Meanwhile, in the browser, players try to guess if the LEDs will be on or off when the blinking ends. They do this by turning the Owl eyes ‘on’ or ‘off’. If the owl eyes match the LEDs, a point is scored. If a point is scored (by any player) Sphero rolls forward!

owledpic

Why Did You Do This?

I went to JSConf US this year (2014) and got a Spark Core device in my swag bag. We also spent a whole day playing around with NodeBots (I did the NodeRockets track)! In the spirit of community and learning and what-not, I decided to demo some of the cool stuff I learned about to the local Memphis Tech community at a Meetup event. The OwLED Guessing Game was what I came up with. It demo’d some cool JS libraries, and took advantage of what hardware I had available.

The presentation was on July 17th, 2014 and kinda flopped. Despite tons of preparation and ensuring that everything would work right, it didn’t. I only had a 15 minute speaking slot, and the Arduino I was using refused to blink during the live demo. It worked just fine an hour earlier, and of course, still works fine now, but alas. Murphy’s law was in full effect.

I Want to Try, But Don’t Have a Spark Core or Sphero…

No worries. The OWL portion can work on its own with the ‘owled-fake.js’ module swapped out for the ‘owled.js’ module. The Sphero code is on a separate branch from master in the GitHub repo. Take a look at the instructions in the README.

Also, there is alternate code in the ‘owled.js’ module for a regular Arduino Uno. A hastily drawn diagram is below…

ArduinoOWLED_bb

Anything Else?

Here’s all the things I used in a big list!

  • Node.JS – Acts as the ‘hub’
  • Express – Serves the web page
  • Socket.IO – Allows events to be ’emmitted’ between the browser and the server in real-time.
  • AngularJS – A nice front-end framework to build the client-side functionality.
  • Redis – Used to keep track of all the blinking outcomes (click the ☰ icon in the browser).
  • Spark Core – The original hardware device used.
  • VoodooSpark Firmware – The firmware used on the Spark Core.
  • Johnny Five – The Node.JS lib to interact with Arduinos.
  • Spark-IO Node Package – Spark Core adapter for Johnny Five.
  • Sphero – A remote controlled, programmable, wireless sphere.
  • Cylon.js – A pretty badass project for controlling hardware with JavaScript.
  • Cylon-Sphero – A Cylon adapter to control Sphero.
  • Fritzing – Used to draw the Arduino diagrams.
  • NodeBots – For inspiration.

HTML5 Games Presentation for MemTech Super User Group

SlideshowShot

Slideshow | Code

Memphis flies under the radar as a technology hub, but there’s still a pretty active community of developers and other technologists that like to meet up and do stuff. I occasionally pop in on the PHP User Group, Ruby User Group, and Python User Group meetups when I get the chance. Every few months, the various user groups organize a joint meetup called the Super User Group Meetup and feature presentations on platform agnostic topics such as development tools, front-end development, processes, and whwatever else people want to talk about.

For the most recent meetup on June 20, 2013, I threw my name in the ring as a presenter and gave a talk about the what, where and how of HTML5 games. It’s nothing terribly complex or in-depth, just a brief survey of the general idea of developing games for the web using web based standards.

This was the first time I’d used the Reveal.js slideshow library. It was a pretty positive experience, especially with the help of slid.es to get started. Embedding live javascript is pretty boss. Also, there are a lot of great plugins, and I definitely took advantage of the ‘notes server’ so I could display the slides on once screen, and my notes on another. I’ll be using Reveal again in the future.

Phaser Starter Project for WebStorm and Chrome: Modular TypeScript, Code Completion, and Live Debugging

Game in Action

DEMO | CODE

Getting started with TypeScript and Phaser on OSX and Ubuntu has been a tricky proposition. My requirements for a development environment were as follows:

  • Use TypeScript as the primary language
  • Break the project into small files – preferably one module or class per file
  • Have all the benefits of TypeScript utilized by my IDE, namely code completion, error checking, and documentation for function signatures
  • File watchers that generate javascript and source maps on file save
  • Live debugging of TypeScript files

Thanks to the latest WebStorm (6.0.2 v129.541 as of this writing), Require.js, and Chrome DevTools, I have a great development environment set up to create Phaser games on OSX and Linux. Here’s how I did it:

First, grab the starter project from my GitHub account (thanks to Jesse Freeman for the inspiration).

git clone git@github.com:ericterpstra/phaser-webstorm-template.git

Then get the following four files from the Phaser ‘build’ folder:

  • phaser.js or phaser.min.js
  • phaser.d.ts
  • phaser-fx.js or phaser-fx.min.js
  • phaser-fx.d.ts

Copy those files to /phaser-webstorm-template/lib/

Then download require.js and put it in the same lib folder.

The contents of the lib folder

The contents of the lib folder

Now start WebStorm 6 (get the EAP version here). Close the existing project if it is open, and go to the welcome screen. Choose Create New Project from Existing Files. Then choose Source files are in a local directory, no Web server is yet configured and click Next.

A file selection window should appear. Find the phaser-webstorm-template folder, select it, and click the Project Root button. Then click Finish.

Find the phaser folder and make it the project root.

Find the phaser folder and make it the project root.

When the project finishes loading, open game/game.ts. After a few seconds, WebStorm should prompt you to add a ‘TypeScript’ file watcher. Click the Add Watcher link.

Click 'Add Watcher' when prompted.

Click ‘Add Watcher’ when prompted.

Once the watcher is added, go the the Webstorm menu (File menu in Linux) and open Preferences…. Click File Watchers under the Project Settings section, and double click the TypeScript entry. When the Edit Watcher window appears, add the following text to the Arguments: field:

 --target es5 --module amd
Edit the File Watcher settings.

Edit the File Watcher settings.

Click OK and return to the code editor. Open game/objects/Player.ts and also game/game.ts if it is not open already. Manually save both files to trigger the file watcher and regenerate the javascript and source map for each file. If this was successfull, the .js and .js.map files will appear underneath their respective .ts files, and can be viewed by clicking the expand arrow (see screenshot below).

Files

You should now be able to use WebStorm and have lots of assistance for TypeScript. Code completion, method signatures, documentation, error reporting, and all the other benefits of WebStorm should now be available.

Code hinting should be working in .ts files.

Code hinting should be working in .ts files.

For live debugging of code, open Google Chrome and point it to http://localhost:63342/phaser-webstorm-template/index.html and open the Chrome DevTools (Cmd-Alt-i on OSX, F12 on Linux). Click the Settings button (the little gear icon in the bottom-right corner of the DevTools window). Check the box next to Enable source maps in the General section.

Enable source maps.

Enable source maps.

Now, from the Sources tab, you should be able to open the Player.ts and game.ts files and set breakpoints and watch expressions and step through the code one line at a time! Awesome, right?

Chrome Debugging

That’s basically it. WebStorm apparently has TypeScript debugging built in as well, but I’ve had trouble getting it to work reliably. Once I do, I’ll update this post with info on live debugging from within WebStorm as well. Also in the works is a screencast and more in-depth explanation of the actual code within the project itself. Stay tuned.

Special thanks to Photon Storm for the Phaser framework, Jesse Freeman for the original Phaser project template, and Luke Hoban for help debugging my modular TypeScript.

Ghost: Just A Blogging Platform: Of the Future

Starting a blog is not difficult. Any Joe Schmoe can start plopping ideas into the public realm with just a few mouse clicks. There are many, many tools available to get a blog rolling: WordPress has dominated the self-hosted blogging landscape for years, Tumblr is ultra-popular with certain crowds, and for some reason people still use Blogger. The landscape is changing, though. Hosted blogging services like Tumblr and Posterous are traded like horses, with users left in the dust in some cases. Also, the WordPress feature set has vaulted beyond blogging tools, and is quickly becoming a full-blown content management system capable of building just about any type of website.

So what is the average blogger to do? Risk investing time and energy into a blogging service that may wind up as a minor acquisition of AOYahooSoft? Or dig through the complexity of WordPress’s ever expanding administration menus? How about neither? A new kid on the block just showed up with two fistfulls of awesome…

Ghost.

Ghost is a new open source blogging platform dedicated solely to dead-simple publishing. It’s goal it to let writers write, and have fun doing it. No crazy heirarchy of menus to wade through, no finicky wysiwyg editor mangling HTML, nothing to worry about except creating delightful posts. Every feature going into the initial release of Ghost will exist to support the prime directive of presenting a sensible, comfortable, and useful writing environment for the web.

The underlying technology powering Ghost will be an example of simplified elegance. NodeJS will act as the foundation, and the Express framework, JugglingDB ORM, and Handlebars template system will provide the scaffolding. This means that 100% of the Ghost platform will be written in a single language – Javascript.

The benefits of using one language for the full stack are obvious. I, personally, would love to focus my attention on one language when creating an application. But there are naysayers out there who would argue that NodeJS is just not the right tool for building a blogging platform, and Ghost would be better served by established frameworks like Rails, Django, or any number of PHP packages. This attitude is a bit short-sighted, in my opinion. If 37Signals thought like this, Basecampe would have been written in PHP, and Ruby might still be an esoteric language on the fringes of the web development world. It is projects like Ghost that will bring Node from marginal to mainstream.

We’ll have to wait a few months, though, as Ghost is still in its infancy. As of this writing, the Kickstarter campaign is reaching its end and is getting close to the stretch goal (after eclipsing the original goal 7 times over). Backers (including yours truly) will get early access this Summer, and the general public will get their hands on it in November. Not only will the code be open source, but a non-profit organization is being formed as we speak to provide reasonably priced blog hosting a-la WordPress.com. Because the service is formed under a non-profit, the risk of acquisition is minimal.

There is a good amount of promotional material available on the Kickstarter page, and the official website. I highly encourage taking a look, especially for anyone with even a passing interest in web publishing. Personally, I’m betting on Ghost as the next big thing, and in five years this post will be proof that I totally called it. Internet hipsters, eat your hearts out.

A simple require.js setup (with canvas and Hammer.js)

I have been reading a few tutorials on HTML5’s canvas tag, and decided to give it a whirl. Rather than bunch everything together in a huge javascript file, like most of the examples I read, I wanted to split files into sensible chunks of code. The RequireJS project has crossed my path on more than one occasion, so I figured it might be a good thing to try. I figured correctly, as it was super easy to set up, and works swimmingly.

There are plenty of great resources out there to learn all about modular javascript, as well as an interesting debate on the proper method of defining modules, but the RequireJS site itself has enough info to get a basic project off the ground. I had to do a bit of experimenting on my own to clear things up in my head, and thought I would post the results here.

The project basically draws a canvas that takes up the entire browser window (and redraws itself when the window is resized). A white dot is drawn on the screen and floats towards the bottom-right corner until the user swipes a finger (using a mobile device) or the mouse pointer (on a lap/desktop). The dot will switch directions to match the swipe. Try it out!. I had intended to get the dot to do more interesting things, but time gets away from me.

The folder structure holds three files in the root, and the rest of the folder structure looks like this:

Screen Shot 2013-05-12 at 9.20.17 PM

Click here for full source

Notice that the only file in the root is index.html. Also notice that the only javascript file referenced in index.html is src/require.js, which has a data-main attribute stuck in there, as well. That data-main attribute references the entry point to the application. RequireJS will automatically append ‘.js’ to the filename, and will run whatever is in that file.

At the top of catToy.js is the following code:

requirejs.config({
  baseUrl: 'src',
  paths: {
    lib: '../assets/lib'
  },
  shim: {
    'lib/Hammer': {
      exports: 'Hammer'
    }
  }
});

This bit of code tells RequireJS what’s what. The baseUrl is a relative filepath that will act as the root for all other file paths referenced in the config block. The paths object is a list of aliases (shortcuts) to other subdirectories that contain code. The key (lib) is the alias name, and the value (‘../assets/lib’) is the file path relative to the baseUrl.

The shim object allows you to define modules that originally weren’t intended to be used with RequireJS. In this case, the Hammer library is referenced, and will export a ‘Hammer’ module that can be used in the project.

Underneath the config block is a function that acts as the main starting point of the application. The first two lines are the most important, in terms of RequireJS.

requirejs(["modules/Stage","modules/Mover","modules/Vector2D"],
  function( Stage,  Mover, Vector2D) {
    ...// application code goes here
});

This is basically a function call that says, “Hey, RequireJS!, do this! And don’t forget to load these three modules before you do it!”

The three modules in question are Stage, Mover, and Vector2D. The first parameter of the requirejs() function is an array of modules that are needed in the function that is passed in as the second parameter. RequireJS will look up the modules, and pass them into the anonymous function, using whatever names you define.

Each of the modules used here are set up to be specifically compatible with RequireJS using a function called define(). The first line of each module is very similar to that of catToy.js:

define(function(){
  ...// code goes here
});

Yeah, that’s it. Just wrap your code in the define() function and it can be used as a RequireJS module. If the module needs to use code from another module, then pass in an array of module names, just like before.

define( ['lib/Hammer'], function(Hammer) {
  ...// code goes here
});

Live Updates in CodeIgniter with Socket.IO and Redis

CODE | DEMO*

UPDATE: This is the third of a three part series on CodeIgniter, Redis, and Socket.IO integration. Please be sure to read the other posts as well.
Part 1: A Sample CodeIgniter Application with Login And Session
Part 2: Use Redis instead of MySQL for CodeIgniter Session Data
Part 3: You are here.

Well here it is, folks, the moment I’ve been waiting for :) Real-time updates that actually work! Socket.IO has been integrated to work its magic alongside CodeIgniter. Now when a user is logged in, updates will tumble in like an avalanche with absolutely no refreshes or any user intervention at all! To catch up on what this is all about, be sure to check out A Sample CodeIgniter Application with Login And Session and Use Redis instead of MySQL for CodeIgniter Session Data before reading this.

Take a look at the video above to see the live updates in action. There are three different browser windows open (Chrome, Firefox, and IE9), each logged in with a different user. The top left browser is the Admin, which will get updated when any user posts a message. The Admin is also a member of team one, so when the admin posts a message, members of team one (bottom left) will see it. The browser on the right is team two, so she will not see anyone else’s posts, but the Admin will see what she posts.

* The demo may or may not be working depending on the state of my VPS. Most of my sample projects so far have been hosted on my shared hosting account, but due to the Redis and Node requirement I had to deploy this project to a VPS that I normally use for development and testing. If I am doing some development or testing, then Apache or Node or Redis might not be working properly – hence the video. Your best option really, is to download the code and try it yourself!

The Socket.IO library makes it painfully easy to work with NodeJS (aka, Node). Prior to this project I knew almost nothing about Node other than what had read in a few short books. I still don’t know much about Node, but I know that I like it and will continue to keep investigating it for future projects. One thing in particular that I think pretty cool in this project, is that all of the Node specific functionality (the real-time message updates) runs mostly parallel to the PHP application. So if Node decides to blow up, the application will still work, only without live updates.

Anyway, enough jibber jabber. Here’s the rundown on the changes to the application, and the highlights of the Socket.IO and Node code. Again, this is not meant to be a tutorial, but rather a show and tell and perhaps a nice piece of code for others to experiment with. Use at your own risk.

Installing Socket.IO

First things first: Install Socket.IO. I already had Node and NPM installed, but I needed a spot to create the node ‘server’ within my project. I created a folder in the project root called ‘nodejs’. Through the wonders of Node Package Management (NPM), I installed the socket.io package, as well as the node_redis package. This was done by simply navigating to the nodejs folder and running:

npm install socket.io
npm install redis

Yeah, that’s it. NPM will create a folder called ‘node_modules’ and download all the dependencies necessary to run the packages. After that I created the cisockServer.js file, and I was off to the races.

To get things working right away, I added code similar to the following, just to get things rolling. The first line instantiates Socket.IO and gets a Node server up and running on port 8080. An event handler is created for the ‘connection’ event, which fires whenever a Socket.IO client connects to the server. When this happens, Socket.IO will emit an event with an identifier of ‘startup’ and attach an object with a message. If the client is listening for the ‘startup’ event, it will receive the message.

var io = require('socket.io').listen(8080);

io.sockets.on('connection', function (socket) {
  // Let everyone know it's working
  socket.emit('startup', { message: 'I Am Working!!' });
});

To actually get the Node server fired up, it’s as easy as node --debug cisocketServer.js to get it going. I added the –debug option because I was using node-inspector for debugging and tracing. There is also an interesting project called Forever available from NodeJitsu that manages one or more Node processes. I use it on my VPS. It’s nice.

The Socket.IO Client

A server is all fine-and-dandy, but it won’t do much good without clients. I created a new javascript file in my CodeIgniter assets folder called ‘socket.js’ to hold all of my Socket.IO related client code. I wrapped most of the code in the MY_Socket namespace so it is more easily accessed by the javascript in main.js. The minimum amount of code needed to work with the server code above is what follows. It simply creates a socket connection, then listens for the ‘startup’ event from the socket connection. When the ‘startup’ event occurs, the attached message will be displayed on the console.

$(function(){

  window.MY_Socket = {

    // Instantiate the Socket.IO client and connect to the server
    socket : io.connect('http://localhost:8080'),

    // Set up the initial event handlers for the Socket.IO client
    bindEvents : function() {
      this.socket.on('startup',MY_Socket.startupMessage);
    },

    // This just indicates that a Socket.IO connection has begun.
    startupMessage : function(data) {
      console.log(data.message);
    }
  } // end window.MY_Socket

  // Start it up!
  MY_Socket.bindEvents();
});

To get this working, all that is needed are a couple more lines in header.php:

<script src="<?php echo base_url();?>/nodejs/node_modules/socket.io/node_modules/socket.io-client/dist/socket.io.min.js"></script>
<script src="<?php echo base_url();?>/assets/js/socket.js"></script>

Now upon visiting the login screen (or any screen, really), the words, “I am working!” will appear in the console.

Joining A Room

Socket.IO has a concept called rooms, which is a nice way to segment broadcasted messages from a server so only a subset of users receive the message. In this application, users will join a room based on their team numbers. Team 1 will join room 1, and so on. The exception here are admins. Admin users can be on a team, but will receive messages from all users regardless of their team. To handle this, I created another room called ‘admin’.

The room joining process starts when a user is logged in. I added a bit of jQuery code to check the current page for team badges, and if any are found, run the joinRoom function. Another way to do this would be to just put a call to MY_Socket.joinRoom() at the top of /application/views/main.php so it runs whenever the main view is loaded.

init: function () {
  ...
  if($('.userTeamBadge').children().length > 0){
    MY_Socket.joinRoom();
  }
}

So the joinRoom function does some interesting things. First it grabs the cookie named, “ci_session” and reads the value. This value is the session ID set by CodeIgniter. This ID will be used to look up some of the other session information stored in Redis by the application’s MY_Session class. When the session ID is obtained, a ‘joinRoom’ event is emitted with the ID attached. If no session ID is found, then nothing happens. The code below is part of the client code in the socket.js file.

joinRoom : function(){
  // get the CodeIgniter sessionID from the cookie
  var sessionId = readCookie('ci_session');

  if(sessionId) {
    // Send the sessionID to the Node server in an effort to join a 'room'
    MY_Socket.socket.emit('joinRoom',sessionId);
  } else {
    // If no sessionID exists, don't try to join a room.
    console.log('No session id found. Broadcast disabled.');
    //forward to logout url?
  }
}

Socket.IO will be listening for the ‘joinRoom’ event on the server. When it hears the event, it will grab the session ID, use it to construct a string that matches the corresponding session key in the Redis database, and get the data associated with that key. The results returned from Redis will contain the rest of the user’s session information, including teamId and isAdmin (indicating if the user is or is not an admin). The result is parsed into a JSON, and the teamId and isAdmin values are used to join the appropriate ‘rooms’.

For any of this to work, a Redis client must be set up to execute Redis commands. The following code is in cisockServer.js.

// Start up a Node server with Socket.IO
var io = require('socket.io').listen(8080);

// Let Node know that you want to use Redis
var redis = require('redis');

// Listen for the client connection event
io.sockets.on('connection', function (socket) {
  // Instantiate a Redis client that can issue Redis commands.
  var rClient = redis.createClient();
 
  // Handle a request to join a room from the client
  // sessionId should match the Session ID assigned by CodeIgniter
  socket.on('joinRoom', function(sessionId){
    var parsedRes, team, isAdmin;

    // Use the redis client to get all session data for the user
    rClient.get('sessions:'+sessionId, function(err,res){
      console.log(res);
      parsedRes = JSON.parse(res);
      team = parsedRes.teamId;
      isAdmin = parsedRes.isAdmin;

      // Join a room that matches the user's teamId
      console.log('Joining room ' + team.toString());
      socket.join(team.toString());

      // Join the 'admin' room if user is an admin
      if (isAdmin) {
        console.log('Joining room for Admins');
        socket.join('admin');
      }
    });

  });
});

Excellent.

Send and Receive Messages

When a user posts a new message, the data is sent to the web server using jQuery’s Ajax function. This happens in the App.postMessage function in the main.js file. If the post is successful, a callback function – App.successfulPost – is executed. In order for the post to be successful, it needs to be processed by the CodeIgniter controller method responsible for saving posts to the database. This method – main.post_message – had to be refactored so that it would not only save the message, but also respond to jQuery’s ajax request with the message wrapped up in the HTML template so it can be sent out to other users.

The HTML template responsible for rendering each individual message was separated out into its own view and saved as /application/views/single_posts.php. It was basically just cut and pasted from the main view.

<div class="otherPost well">
  <div class="otherAvatar">
    <img src="../../assets/img/avatars/<?php echo $avatar ?>.png"
         alt=""
         data-title="<span class='badge badge-info'><?php echo $teamId ?></span> <?php echo $firstName ?> <?php echo $lastName ?>"
         data-content="<?php echo $tagline ?>">
  </div>
  <div class="otherPostInfo">
    <div class="otherPostBody"><p><?php echo $body ?></p></div>
    <hr/>
    <div class="otherPostDate"><p class="pull-right"><?php echo $createdDate ?></p></div>
  </div>
</div>

In order to populate that template, CodeIgniter’s Loader.view method was used with the third parameter set to ‘true’ so it will return data instead of immediately rendering the view in the browser. The view is then loaded into the response data as a string, along with the user’s teamId value, and the HTML string that will be prepended to the user’s own message list. The following code is from /application/controller/main.php (the Main controller).

function post_message() {
  ... save message to db code ...

  if ( isset($saved) && $saved ) {
    // Gather up data to fill the message template
    $post_data = array();
    $post_data = $this->user_m->fill_session_data($post_data);
    $post_data['body'] = $saved['body'];
    $post_data['createdDate'] = $saved['createdDate'];

    // Create a message html partial from the 'single_post' template and $post_data
    $broadcastMessage = $this->load->view('single_post',$post_data,true);

    // Create an html snipped for the user's message table.
    $myMessage = "<tr><td>". $saved['body'] ."</td><td>". $saved['createdDate'] ."</td></tr>";

    // Create some data to return to the client.
    $output = array('myMessage'=>$myMessage,
                    'broadcastMessage'=>$broadcastMessage,
                    'team'=>$post_data['teamId']);

    // Encode the data into JSON
    $this->output->set_content_type('application/json');
    $output = json_encode($output);

    // Send the data back to the client
    $this->output->set_output($output);
  }
}

The response object is sent back to the jQuery callback function, and it begins the process of broadcasting the message out to all the appropriate users. This really only takes one extra line of code in App.successfulPost.

successfulPost : function( result ) {
  ...
  // Send socket.io notification
  MY_Socket.sendNewPost( result.broadcastMessage, result.team );
}

All this does is send two pieces of information to the MY_Socket.sendNewPost function. The MY_Socket.sendNewPost function will simply take the message and teamId value and send it to the Node server by emitting a Socket.IO event.

sendNewPost : function(msg,team) {
  MY_Socket.socket.emit('newPost',msg,team);
}

When the ‘newPost’ event is handled on the server, it will relay the message to the appropriate team room, and also to the ‘admin’ room.

socket.on('newPost', function (post,team,sessionId) {
  console.log('Broadcasting a post to team: ' + team.toString());

  // Broadcast the message to the sender's team
  var broadcastData = {message: post, team: team};
  socket.broadcast.to(team.toString()).emit('broadcastNewPost',broadcastData);
 
  // Broadcast the message to all admins
  broadcastData.team = 'admin';
  socket.broadcast.to('admin').emit('broadcastNewPost',broadcastData);
});

The ‘broadcastNewPost’ event is emitted twice, and will therefore be handled twice by the client. This is not normally a problem, unless there is an admin with the same teamId as the sender. Then the admin will receive the message twice, and duplicate messages will be displayed on the screen. To correct this, a little logic prevents the message from being displayed twice. The message attached to the ‘broadcastData’ object is forwarded to the App.showBroadcastedMessage function.

// on 'broadcastNewPost' update the message list from other users
updateMessages : function(data) {
  // Because the message is broadcasted twice (once for the team, again for the admins)
  // we need to make sure it is only displayed once if the Admin is also on the same
  // team as the sender.
  if( ( !userIsAnAdmin() && data.team != 'admin') ||
      ( userIsAnAdmin() && data.team === 'admin') ){
    // Send the html partial with the new message over to the jQuery function that will display it.
    App.showBroadcastedMessage(data.message);
  }
}

When the App.showBroadcastedMessage function receives the message, it appends it to the top of the list of messages from other users using simple jQuery.

showBroadcastedMessage : function(messageData) {
   $(messageData).hide().prependTo(App.$otherMessages).slideDown('slow');
   //App.$otherMessages.prepend(messageData);
   App.setElements();
   App.setupComponents();
 }

Whew. That’s it! The journey is complete.

My First jQuery Plugin: VintageTxt

VintageTxt 
Default

DEMO | SOURCE

Ever hearken back to the good ol’ days of the Apple II, with its monochrome screen and visible scanlines? No? Me either, really. I don’t even know what hearken means. But I do know that vintage looking stuff is cool, and people love it when all that is old is new again. So here is a jQuery plugin (new) that injects a green monochromatic scanlined fake computer screen (old) right onto any webpage. You can even make it type out a bunch of text, one character at a time – like that stupid computer from Wargames. No annoying voice-over though. And of course there is an input prompt, so you can bang away at your keyboard while pretending to break through 8 levels of top secret encryption to re-route the protocols through the mainframe and unleash your most advanced viruses… all while chanting, “enhance.”

Why make this? Fun, naturally. Plus I’ve been wondering lately what it would be like to make a jQuery plugin. I know I’m a little late to the jQuery party, and all the cool kids have move on bigger and better things, but the ability to whip up a jQuery plugin seems like one of those skills a self-respecting web developer should acquire at some point. Two helpful guides stocked the pot, and I threw in a bit of my own spicy sauce as I went along. I’m fairly satisfied with the end result, and the knowledge gained. To play around with a fully functional demo, click the link or image above. But to have some real fun, go grab the source from GitHub and VintageTxt your face off!

AngularJS SignIt! – Custom directives and form controls

Note: This is a companion post to Example CRUD App – Starring AngularJS, Backbone, Parse, StackMob and Yeoman. If you haven’t read that yet, please do so, otherwise this might not make much sense.

The most prominent feature, by far, of AngularJS SignIt! is the signature pad. It’s a fixed-size canvas that can be drawn upon with a mouse pointer or finger. The code for this wonderful widget is provided as a jQuery plugin by Thomas Bradley. There are a few more features for the signature pad than I use in this app, and I encourage you to check out the full documentation if you get a chance. It’s pretty great.

In order to implement the signature pad into my form, It must be a required field, and have the data included with the other fields when the form is submitted. The sig pad works by creating objects of x/y coordinates that correspond to marks on the canvas. When drawing on the pad, all that data gets set into a hidden form field. The data from that field is what needs to get into the Angular scope, and get validated by Angular’s form validation routine. Oh, and Angular somehow needs to fire the custom validation function built into the signature pad.

Luckily, this is the type of thing directives were built for. Custom directives let you create custom html tags that get parsed and rendered by Angular. So to start out, I created a custom directive called sigpad that is used by placing <sigpad></sigpad> in my HTML. The sigpad tag then gets replaced by the directive’s template HTML. The template for the HTML5 signature pad is just the default snippet taken directly from the signature pad documentation. See below:

<div class="control sigPad">
  <div class="sig sigWrapper">
    <canvas class="pad" width="436" height="120" ng-mouseup="updateModel()"></canvas>
  </div>
</div>

The logic for the directive is defined in a separate Angular module (see directives.js for full code). Take a look at the code below, and be sure to review Angular’s documentation on directives. The Angular docs give a great conceptual overview, but the examples are a bit lacking. I reviewed the docs many, many times, and still needed some help from the mailing list to get this working correctly (thanks P.B. Darwin!).

My biggest stumbling block was not using ngModelController, and instead trying to manipulate scope data directly. When working with a form, Angular provides all sorts of awesome code to work with data and do some validation. Basically, it all went down like this…

Insert the sigpad directive into the form with

<sigpad ng-model='user.signature' clearBtn=".clearButton" name="signature" required></sigpad>

Now Angular knows to replace the sigpad element with the template defined earlier. After this happens, Angular runs the linking function which contains all the logic for the directive. The little snippet shown below is in the linking function. It uses jQuery to select the template element (passed into the linking function as ‘element’) and runs the signaturePad function from the signature pad API. This is what creates the actual, drawable canvas.

var sigPadAPI = $(element).signaturePad({
                             drawOnly:true,
                             lineColour: '#FFF'
                           });

The ng-model=’user.signature’ bit is key. This is how data is shared between the signature pad and Angular. Also, go back up and look at the template. You will see ng-mouseup="updateModel() as an attribute of the canvas element. This tells Angular to run the updateModel() function when your mouse click ends on the signature pad. The updateModel() function is defined in the linking function of the sigpad directive.

When the updateModel() function is executed, it will wait for a split second so the signature pad can finish writing data to its hidden form field, then it will assign all that data to the Angular model value of the directive. Sounds confusing, and it is. The signature pad is off doing its own thing, completely oblivious to the fact that it is in an AngularJS app. It is Angular’s responsibility to grab data from the sigpad to get that data into its own scope. That is what $setViewValue is for. It hands the signature data over to Angular, so when the form is submitted, Angular has it available in scope.

Below is the entire directive for the drawable signature pad. You can see that it relies heavily on the signature pad API, but only after certain events handled by Angular have occurred.

.directive('sigpad', function($timeout){
  return {
    templateUrl: 'views/sigPad.html',   // Use a template in an external file
    restrict: 'E',                      // Must use <sigpad> element to invoke directive
    scope : true,                       // Create a new scope for the directive
    require: 'ngModel',                 // Require the ngModel controller for the linking function
    link: function (scope,element,attr,ctrl) {

      // Attach the Signature Pad plugin to the template and keep a reference to the signature pad as 'sigPadAPI'
      var sigPadAPI = $(element).signaturePad({
                                  drawOnly:true,
                                  lineColour: '#FFF'
                                });
     
      // Clear the canvas when the 'clear' button is clicked
      $(attr.clearbtn).on('click',function (e) {
        sigPadAPI.clearCanvas();
      });
     
      $(element).find('.pad').on('touchend',function (obj) {
        scope.updateModel();
      });

      // when the mouse is lifted from the canvas, set the signature pad data as the model value
      scope.updateModel = function() {
        $timeout(function() {
          ctrl.$setViewValue(sigPadAPI.getSignature());
        });
      };      
     
      // Render the signature data when the model has data. Otherwise clear the canvas.
      ctrl.$render = function() {
        if ( ctrl.$viewValue ) {
          sigPadAPI.regenerate(ctrl.$viewValue);
        } else {
          // This occurs when signatureData is set to null in the main controller
          sigPadAPI.clearCanvas();
        }
      };
     
      // Validate signature pad.
      // See http://docs.angularjs.org/guide/forms for more detail on how this works.
      ctrl.$parsers.unshift(function(viewValue) {
        if ( sigPadAPI.validateForm() ) {
          ctrl.$setValidity('sigpad', true);
          return viewValue;
        } else {
          ctrl.$setValidity('sigpad', false);
          return undefined;
        }
      });      
    }
  };
})

And what about the tiny signatures that show up in the signatories list? Also a custom directive. This one is smaller, but still tricky. The signature is displayed as an image on-screen, but a canvas element is still required to generate the signature from raw data before it can be converted to an image.

The directive is implemented with <regensigpad sigdata={{signed.get('signature')}}></regensigpad>. The ‘signed’ value is a single signature in the signature collection pulled from the back-end when the user picks a petition. the signature data from signed is passed into the directive scope using scope: {sigdata:'@'}.

When a list of signatures is retrieved, each signature record (including first & last name, email, and signature data) goes into a table row using ngRepeat. The regensigpad directive is executed for each row. The linking function will create a canvas element and make a displayOnly signature pad from it. The signature drawing is regenerated from the data, and then the canvas is converted to PNG format.

This PNG data is then used in the pic scope value, which is bound to the ng-src of an img tag. This img tag is the directive’s template, and will be inserted into the page. The full code for this directive is below.

.directive('regensigpad',function() {
  return {
    template: '<img ng-src="{{pic}}" />',
    restrict: 'E',
    scope: {sigdata:'@'},
    link: function (scope,element,attr,ctrl) {
      // When the sigdata attribute changes...
      attr.$observe('sigdata',function (val) {
        // ... create a blank canvas template and attach the signature pad plugin
        var sigPadAPI = $('<div class="sig sigWrapper"><canvas class="pad" width="436" height="120"></canvas></div>').signaturePad({
                          displayOnly: true
                        });
        // regenerate the signature onto the canvas
        sigPadAPI.regenerate(val);
        // convert the canvas to a PNG (Newer versions of Chrome, FF, and Safari only.)
        scope.pic = sigPadAPI.getSignatureImage();
      });
    }
  };
});

But that’s not all! You might have noticed that the select box holding the names of each petition looks kinda fancy, and allows you to type stuff to filter the list. This fancy form control is the select2 widget which is based of the Chosen library.

I didn’t have to write my own directive for it though. The Angular-UI project has already done the honors. Angular-UI is an open-source companion suite for AngularJS. It provides a whole pile of custom directives, and even a few extra filters. Many of the directives are wrappers for other widgets and open source projects, like CodeMirror, Google Maps, Twitter Bootstrap modal windows, and many more. It’s definitely worth looking into for any AngularJS project.

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