I know there are about a thousand blog posts on implementing push notifications in a Windows Phone 7 application. But having now implemented push notifications a couple times into WP7 projects, I felt like something was missing from the community knowledge base. So, in order to try to cover WP7 Push notifications for the uninitiated, I’m putting together a set of posts will try to cover the following topics:

1. Windows Phone 7 Push Notifications (10,000 Foot View)
2. Implementing Push Notifications on a Device (with Project code)
3. Testing Push Notifications On My Device Without Writing a Goddamn Web Service (Also, How To Write A WP7 Push Service in PHP)

Windows Phone 7 Push Notifications (10,000 Foot View)

The Windows Phone 7 push notification is actually an extremely elegant way of doing push notifications. Personally, I love it. I’ll walk through the steps conceptually here and then mirror the steps in the code post.

(Note to experts: I may be getting some of the details about how this works in the underlying architecture wrong. However, this is how it seems to me that it works and it makes sense this way.)

Step 1: Say “Hey, phone! I want to send you push notifications about some stuff.” When you do this, you’re doing it with a couple of conditions. The first is that you’re giving your specific push service a name (like “Bob” but hopefully a little more specific).

Next, you’ll need to determine if you want to use the “Toast” notification or the “Tile” notification or the “Raw” notification or some combination of these three. When you know what kind of notifications you want, you’ll basically write a magic piece of code which communicates to the magical push notification fairy, who, in return for your good deeds, gives you a device/application specific URL that you will use to send notifications to your phone.

You think I’m kidding. I’m not. As a preview, the code you need to write is: “myPushStuff.Open()”. And that’s it. Then you just wait for the magical push notification fairy to give you the URL you’ll use to send notifications to your phone.

You don’t actually need to send information about toast and tile to the push registration service. However, if you decide later on thatyou actually wanted to send a toast notifications, not a tile notification, your old URL won’t work… you’ll need to save a new one. Don’t know why or how exactly this happens… just passing along helpful information.

If you’re looking for information about the difference between tile, toast and raw notifications, the image below was stolen from the msdn article that talks about the differences. Go read about it there… I won’t stoop to copying and pasting all their excellent information into my blog post.

Step 2: Once you have your magical URL, save it in such a way that whatever webservice you’re using can recognize which phone it’s tied to. Maybe you’re saving it along with a username or with a zip code (like with a weather service). In any case, you’ll want to be able to send the right push notifications to the right phones.

When the time comes to send the notification, your webservice will need to send an XML chunk created for your notification (see details here) to the phone-specific URL. Then, the Microsoft Push Notification Service handles your push request and forwards it to the phone, sending a response telling you that it worked (or didn’t work).

I’ve got my gripes with Windows Phone 7, but the push notification implementation ain’t one of them. It’s very straightforward and can be implemented on the phone with very little code and on a server with similar ease. If you’re a newbie mobile developer and this looks complicated, go try to implement push notification on Android or iOS. For all you Android and iOS people out there I would like to say:

Ha.

The next post will walk through the steps to register your app for push notifications. I’ll post a link to it in this post when I get it up.

The very latest and greatest version of the MIX Outsider application is up and ready for download. Mostly text-building fixes and settings updates.

Also, check out the MIX Outsider website, built with loving care by Jason Alderman (Twitter: @justsomeguy)

If you download the app above, you’ll notice it is in the *.xap format, which is the format for all Silverlight based Windows Phone 7 mobile apps. Perhaps you’ve never side-loaded a WP7 app before or perhaps you don’t have a Windows Phone 7 device. Fear not! If you have the Windows Phone 7 developer tools, you can load the app to your emulator and just run it from there.

The following 90 second video show you how. It really is so easy that it takes less than 90 seconds.

Sideloading the MIX11 Outsider App To The Emulator from Matthias Shapiro on Vimeo.

Have fun and I’ll see you at MIX11!

UPDATE (4/9/2011) : MIX Outsider has been updated to fix some “no network” issues and refine the message creation.

Download MIX Outsider (for sideloading)

MIX11 Outsider is the MIX11 app that doesn’t care about your schedule. It cares about something more important: the people you want to talk to, meet, or otherwise hang out with at MIX. Using a map of the conference floor and a simple “battleship” mapping metaphor, you can tweet, email or text your position at the conference. Don’t eat alone in awkward silence… instead find that Twitter friend who doesn’t have a clear picture of themselves in their avatar. Don’t spend half your pre-keynote time waving your hands in the air. Just tap where you are on the map and send out a link like this one.

http://mixoutsider.com/H60

And a quick video of the application in action

MIX11 Outsider Windows Phone 7 App Screencast from Matthias Shapiro on Vimeo.

I wish I could introduce this app with a bit more fanfare, but I’ve been waiting since Monday for my app to get through the submission process. I was hopeful that, if I got it in a week before MIX, I would make it in time for the conference. At the moment, that hope fades. As a result, until I can get the app into the Marketplace, it will be available here for download so Windows Phone 7 devs can sideload it onto their phones

MIX Outsider (for sideloading)

(Don’t know how to sideload an app? James Ashley has a great post on sideloading to the emulator or to a device.)

The funniest thing is that the “big idea” in this app isn’t really even the app itself. The app is really just the most complete extension of the original idea.

You see, last year at MIX 10, there was a massive coordination effort among my colleagues to try and sit together during the keynote talks. This led to e-mails, text messages, phone calls, and tweets with hard to understand directions like

“We’re 12 rows from the back in the middle of the far right side as you come in (stage left).”

But my decision to do something about it came when a friend spent 10+ minutes with his lunch plate in hand trying to find our table. I thought, “This is absurd… there must be a better way to find people.”

Unfortunately, my GPS did not work very well inside the conference… which didn’t really matter since (I assume) no one wants to open up a Google Maps or Bing Maps to find people inside a building.

So Jason Alderman and I discussed the problem and thought that it might be fun to do a “Battleship” metaphor for finding people at MIX11, laying the grid on a map of the conference floor. Based on that concept, I wrote a little application that allows user to tap to see where they are and send that information out. It then collects all the messages sent out with the app and shows them on the map with the users’ twitter avatars.

Users can send public messages using Twitter or private messages via text message or e-mail. Private messages are not broadcast and cannot be seen by anyone. They contain only the helpful link to the MIX Outsider reference website (designed by the aforementioned Jason Alderman) without any identifying information.

But my biggest hope is that this application gives people a point of reference so that even people who don’t have a Windows Phone 7 device can see the tweets, reference the website and still find the people they want to meet at MIX11.