Shrtr

Note: to read the background, and reasons for developing Shrtr for Windows Phone, see my main blog post.

Having decided to take up the DVLUP challenge (see post on my main blog), I sat down to write my URL shortening app, Shrtr.

Development environment

My first set of problems started with installing the development environment itself. WP8 SDK requires Windows 8 and higher (why W8? because Microsoft decided to take a page out of Apple's book of "Douchy tricks to drive sales of new technologies by limiting dev tools to new environments").

I already had a W8 partition on my trusty T400, which I upgraded to W8.1 Pro. (Side note: despite being over 5 years old, the Lenovo T400, with a fast SSD and 8GB of RAM, is a surprisingly snappy, reliable development machine). I installed VS 2013, but then hit the second snag: MS only allows installation of the WP emulator on processors that support a Hyper-V feature called SLAT (why? see "why W8?" above Update: I finally figured out why Hyper-V is used: the WP8 emulator is implemented as a separate virtual machine, which is very smart, and useful. However, I believe it can run on Windows 7 as well). This feature only exists in the 2 recent generation of Intel processors.  So I couldn't use an emulator in the development of the app. Luckily, I have a Lumia 620 on hand, and Visual Studio allows debugging on a device. It's a bit slower, but you get to experience the behavior of the final product earlier.

To complete the dev environment experience, I used Chocolatey (think of it as "apt-get for Windows") to install Git for Windows, and Paint.Net (which imho MS should have acquired and turned into the default Windows Paint app years ago). I also installed the latest version of Node and Node tools for VS (currently in alpha), to allow me to run both server and client.

Architecture

By design, the app allows you to type or paste a proper URL, select one of (currently 6 supported) shortening services, and get back a short URL. You will then be able to email/share/copy-paste the short URL, from within the app.

Most online shortening services have (some sort of) an API. It can be RESTful, or just a URL you GET or POST the long URL to. Some require that the long URL start with a protocol ('http'), some don't. Some require a developer key, some don't care. Some support custom ("vanity") URLs, and some don't.
I built an abstraction round the actual API calls, that externalizes a simple call, specifying service name, and long URL as parameters. This way I could easily add new shortening services with few parameters (URL, API method, how to parse the reply, key, should the URL start with protocol?).

Since I intended to add more features later (if anyone will be interested in the app), I immediately saw the need to break the app to a server and client components.

Client

The first version to Shrtr was a Phonegap cross-platform app, written entirely in JavaScript. It ran well on Android and iOS, so I downloaded the WP8 Phonegap template for VS, and attempted to copy-paste in my app. Despite claims of Phonegap working transparently on WP, I ran into several issues:

1. Phonegap events are not completely supported on WP, breaking my code. Yes, there are workarounds, but I was hoping to having to deal with as few code changes as possible.
2. The design that looks great on iOS and Android (Webkit-based browsers) just breaks on mobile IE.
3. I ran into some cross-domain AJAX call issues.

My second attempt was to try the Javascript WP8 template provided in VS, and just shoe in the app logic. Things ran aground pretty quickly. Around that time I came to the realization (see Architecture) that the logic will be broken out to a server, so my third attempt at the app was to use the default WP8 template. I haven't touched XAML in a long while (since my happy .Net days in 2011), but returning to C# was easy, and VS is a helpful, rewarding dev environment.

Visual Studio now comes with NuGet built in. Think of NuGet like Node's NPM for VS. It easily installs installation external components and libraries from a repository, extending your project and development experience. I used it to install RestSharp - for easy consumption of my REST service, and Windows Phone Toolkit - added several phone controls, such as a versatile list control, and a highly configurable textbox. 

UI

Visual design of UI has never been my strong suite, so my single screen still looks like "My FIRST XAML", but it's functional, and it works (btw, if you think you can help me make it look nicer, please drop me a note or comment). 

Logic

After finishing the UI and tying all the events to their respective handlers, I wrote a couple of classes encapsulating the calls to the backend service, the service request and response, and used RestSharp to serialize/deserialize the request and response. Once you grasp the async calls Lambda syntax, it becomes easy to write and handle the service calls. And RestSharp makes reading/writing JSON a snap.

The app has basically 2 calls to the server:

1. Get a list of shortening services to show in the services list.
2. Shorten a provided URL, using a specified service.

Flow

You type/paste the long URL into the textbox. The length limit is displayed in the bottom right. You can select the service from the list control, or reuse the one you've selected before. You submit the call by hitting the little scissors on the right, or hitting Enter on the keyboard. Selecting a different service will resubmit the existing URL to the new service.

The short URL is displayed in a simple textbox. The app then uses the AppBar to expose the available actions the user can take with the shortened URL, using standard phone tasks.

I then added some local settings to allow saving the last service you've used for the next time. I may add some functionality around saving all the URL history - if anyone asks for it.

Server

My last 2 major projects were written in Node.js, using the Express framework, and I saw no reason to change a winning horse. Furthermore, since the logic for my original Phonegap app was written as Javascript classes, it was fairly easy to move them to server side code, without to many changes.

The server exports a RESTful service, accepting and returning JSON. It exposes 3 methods:

1. A list of services supported.
2. The shortening function, accepting service name and long URL.
3. A ping service - allowing to check if the service is up.

I used the local Node server to test my app and debug on both ends. Chrome developer Tools is your friend here.

To quickly deploy and test a Node server, I use Heroku. After a short installation of their command line tool, provisioning the server is one line, and deploying is a mere git push command. I'm considering trying Microsoft Azure for my next project, but have yet to find out how to use it for free :).

After that, I added an index page, for people who just drop by, with links to the app. And yes, my HTML/CSS can stand some face lifting as well :).

Publishing the app

Publishing the app was rather easy. First, you need a developer account with Microsoft (which I got for free for a year - you can get it pretty easily, from either MS or Nokia). 

Clean your app from unnecessary resources. Fill the manifest XML correctly, making sure you pick up the right permissions - I only needed the ability to connect to network. 

Then, log into your developer account, upload the xap, fill in the data, make the right choices (supported sizes, languages and countries; good description of your app; good category), upload a couple of screen shots (easily taken on the device), and... wait. And wait. And wait for Microsoft to qualify your app. Since my app is quite simple, it went through certification the first time - your milage may vary.

After my app was published in the store, I had to "introduce" it to my Nokia DVLUP account, which took a couple more days. But eventually, I got the XP points for the challenge, and my award device is on its way!

Next steps

Since the logic now completely resides on the server side, I can add more shortening services at will, and I can add more clients. In fact, I did. 

Right now there's a Chrome extension in the Chrome web store, and in my free time (yeah right :)), I'm working on an Android app.

I'm hoping I can solicit some help in the UI department, that will make the app shine. But either way, I learned how to develop and publish a WP8 app the hard way, so the next one would be a snap.

Download links

1. Web site
2. Windows Phone 8 app
3. Chrome extension

Display JSON results

JSON (JavaScript Object Notation) is a great straight forward way to transfer information from one application/server to another. It's string-based, array-oriented, and does not carry with it the redundancy of XML or (shudder) SOAP. And the best feature in a web application: it's immediately transferable to a JavaScript object, without the need for (an explicit) parsing.

Add to the mix jQuery - a JavaScript framework that makes using JavaScript and writing dynamic web pages a snap. Once I picked it up, I couldn't go back. jQuery is now embraced by many - including Microsoft and Google, who include it in their default web templates, and provide hosted CDN versions of its latest versions.

jQuery shines when it comes to AJAX transactions - you can get a JSON result from a web service using one instruction! Going over the reply is also a snatch. I found myself many times just needing to dump the results on the page - either for debugging purposes, or so I could copy/paste them somewhere.

Here is a short code snippet that I use to get a JSON result from a local web service (a remote request requires JSONP - future post), and dumps the results in a form of a list. It assumes a single-level array reply and that you have a <DIV> element on the page called "result":

Explanation:

1. Line 1 includes version 1.5.2 of jQuery from the Microsoft CDN
2. Line 4 will make sure the function will run when the document has been fully loaded and drawn
3. Line 5 calls the JSON service and sends the results to a function
4. Line 8 iterates over the result object and creates an array of <LI> elements
5. Line 14 creates a new <UL> element, applies a CSS style to it, attaches the <LI> elements and places it inside the result <DIV>

That simple!

1st Netduino Project: Traffic Light

While I'm dabbling in HTML5, iPhone and Android projects at this particular point in time, I chose to open this blog with a project I'm passionate about. I've been following the Arduino revolution for years now, but always from a far. Although I have some electronics background in my ancient past (try: middle school electronics kits), I see myself a s a software professional. Having had the distinct "pleasure" of working in assembler, I decided that's as close I'd ever get to speaking to real hardware.

And then I found out about the Microsoft .Net micro framework. It seems I can take my .Net skills and transfer them to the hardware world! I can make LED lights turn on and off! I can react to button clicks rather than keyboard and mouse events! But on a more serious note, I can implement a standalone web server that allows me to perform operations remotely. I can read/write to an SD card. I can control a vast collection of electronic components and analyze information from a myriad of sensors. All this with a very small upfront investment. I'm in.

What do you need:

1. An arduino board that supports the .Net micro framework. There are several out there, but I chose the Netduino Plus. At $60 it provides an Ethernet port and a microSD card reader on board, saving you the need to wire those later. I got it off Amazon, along with the breadboard (see 3).
2. Free software: SDK and drivers (most software associated with Arduino is open source, even (shock!) the .Net micro framework from Microsoft. This page has a full list of what you'll need, including a good installation guide that will take you through installing, writing your first program and debugging it. 
3. To develop software you use Visual Studio (you can use the free Visual C# Express version). 
4. Some cheap components. I got a mini breadboard for $3. A breadboard allows you to play with circuits and components without the need to solder anything. There are no mistakes and most components are tolerant with the involved voltages. Heck, I found out that one of the LEDs I got was dual-colored - you get a different color if you plug it in the other way. That was a nice surprise.
   I also got a couple of wires and color LEDs from my local FRY's (at $0.49 each - you can get them at $5/40 - I just didn't need that many).
5. Plenty of internet reading: instructions, projects, suggestions. I enrolled in the Netduino forums and have been so far assisted with some issues. Every one there is enthusiastic and helpful. All are hobbyists - none are trolls.
6. A free weekend.

Later on you may want to buy more components, like shields (Arduino add-on boards) sensors (light, touch, accelerometers), wireless network adapter (like XBee), LCD screens, joysticks - whatever.
My recommendation is: even though the components are relatively cheap (with the exception of XBee and a GPS shield, they are almost always below $20, most are even cheaper), avoid buying them until you feel sure you've grasped the basics and are ready to proceed.

Programming:
The "Hello, World" project of  the Arduino world is called "Blinky". You get to blink the on-board LED, and later read the on-board button to control the LED.

Visual Studio automates the deployment of  allows you to do a step-by-step debugging on the device. This is an amazing way to develop for hardware. Of course, you get the assortment of tools you're already used to as a .Net developer.

I asked myself what can I do with an LED, and came out with the done-to-death idea of a Morse code Signal Emitter (I called it "Morsey"). You feed it an English string and it yields a string of dashes and dots using the LED. The next step was to use the button to start/stop the signaling. And then came the notion of using a separate thread to be able to pause and resume the signaling - in short, I spent time honing my skills, such as they are, preparing for more complex projects.

Traffic Light project:
But before I was ready to move on to my next project, which will involve an LCD display ($10 on Amazon), I decided to test my breadboard skills and developed this small project called "Traffic Light".

Made of one tiny breadboard, 3 colored LEDs, 7 wires and about 40 lines of code, it simulates a traffic light's color change, using a separate thread, and the LED class I carried over from "Morsey".

You can see the end result in this video and I should really start to remember not to talk while zooming with this camera - it records the zoom noise over your voice):



I found a nice (free) application called Fritzing that allowed me to design my circuit design and share it with other hobbyists. Here's what the above circuit looks as a Fritzing design:

And Fritzing automatically turns it into a schema you can use to share with electronics professionals, using standard conventions. Just in case you'd like to mass-produce your project one day:

If you want to get the full code, including these images and the Fritzing file, just git it here: https://github.com/TravelingTechGuy/TrafficLight.

And yes, I wrote "Git", not "get". If you don't know what Git is, or how to use it, the page also provides a zip download, but you better get used to it, as I'm going to use github to share all my code on this blog (and thanks to Jason for introducing me to git in the first place).

Well, this is done, on to the next project.