Mobile: Push for
Sync & Notifications
By Mike Willbanks
Software Engineering Manager
CaringBridge

About Mike…
• Software Engineering Manager at CaringBridge
• Open Source Contributor
• Organizer of MNPHP
• Where you can find me:
 Twitter: mwillbanks
 G+: Mike Willbanks
 IRC (freenode): lubs
 Blog: http://blog.digitalstruct.com
2

Agenda
• Overview of Push Notifications
• Android Push Notifications (C2DM)
• Apple Push Notifications (APNS)
• Microsoft Push Notifications
• BlackBerry Push Notifications
• Questions
 Although you can bring them up at anytime!
3

Overview
What are they?
What is the benefit?
High level; how do these things work?

What Are They
• Push Notifications…
 Are a message pushed to a central location and delivered to you.
 Are (often) the same thing at a pub/sub model.
 In the Mobile Space…
• These messages often contain other technologies such as alerts, tiles,
or raw data.
5

In Pictures…
6

Benefits of Push Notifications
The benefits of push notifications are numerous; the
question is if you have an app and you are running services
to poll; why would you do such a thing!

One word… Battery Life
8

Impact of Polling
9

Battery Life
• Push notification services for mobile are highly efficient; it
runs in the device background and enables your application
to receive the message.
• The other part of this; if you implemented it otherwise you
would be polling. This not only wastes precious battery but
also wastes their bandwidth.
 NOTE: This is not always true; if you are sending data to the phone
more often than a poll would do in 15 minutes; you are better off
implementing polling.
10

Can We Deliver?
11

Delivery
• When you poll; things are generally 15+ minutes out to save
on battery. In a push notification these happen almost
instantly.
 We’ve generally seen within 1-3s between sending a push
notification to seeing it arrive on the device.
• Additionally; push notifications can be sent to the device
even if it is offline or turned off.
• However, not all messages are guaranteed for delivery
 You may hit quotas
 Some notification servers only allow a single message to be in
queue at 1 time (some group by collapse key), and others remove
duplicates.
12

How These Things Work
The 10,000 foot view.

10,000 Foot View of C2DM
14

10,000 Foot View of APNS
15

10,000 Foot View of Windows Push
16

10,000 Foot View of who?
17

Oh, that’s right Blackberry!
18

Walking Through Android
Understanding C2DM
Anatomy of a Message
Pushing Messages
Displaying Items on the Client

Understanding C2DM
• It allows third-party application servers to send lightweight
messages to their Android applications.
• C2DM makes no guarantees about delivery or the order of
messages.
• An application on an Android device doesn’t need to be
running to receive messages.
• It does not provide any built-in user interface or other
handling for message data.
• It requires devices running Android 2.2 or higher that also have
the Market application installed.
• It uses an existing connection for Google services (Through the
Google Market)
20

Registering for C2DM
• First things first – you must sign up to actually utilize C2DM
 http://code.google.com/android/c2dm/signup.html
 C2DM only works on Android w/ Google Market; if you use get a
new Amazon Kindle Fire it would not work there.
• We will be utilizing a library based on ZF
 https://github.com/mwillbanks/Zend_Service_Google_C2dm
21

Anatomy of the Mobile App
22

How the Application Works
• We must update the Manifest file to state additional
permissions.
• We will then create a broadcast receiver that will handle
the messages and registration.
23

Example Manifest
24

Handling the Registration (or Unregistering)
• Registration / Registration Updates and Unregistering.
• Registration is generally on app start up.
• Be nice and allow your users to unregister from the push
notification service 
25

Example Receiver
More at: http://bit.ly/bxOoMO towards end of article.
26

Implementing a Server
• Enough Java already; it is a PHP conference!
• Implementing the actual server is quick and pain free…
 At least in my opinion (I did build this PHP implementation of
C2DM)
• Some limitations
 200K messages per day by default; use them wisely however you
may request more.
 1K message payload maximum.
 You must implement incremental back off.
27

How the Server Works
28

Using Zend_Service_Google_Gdata
• Example is on GitHub:
https://github.com/mwillbanks/Zend_Service_Google_C2dm
 Code was a little too large to attempt to fit it into a slide 
29

Apple Push Notifications
A brief walk-through on implementing notifications on the
iPhone.

Understanding APNS
• The maximum size allowed for a notification payload is 256
bytes.
• It allows third-party application servers to send lightweight
messages to their iPhone/iPad applications.
• Apple makes no guarantees about delivery or the order of
messages.
• An application on an iPhone/iPad device doesn’t need to be
running to receive messages.
• Message adheres to strict JSON but is abstracted away for us in
how we will be using it today.
• Messages should be sent in batches.
• A feedback service must be listened to.
31

Preparing to Implement Apple Push Notifications
• You must create a SSL certificate and key from the
provisioning portal
• After this is completed the provisioning profile will need to
be utilized for the application.
• Lastly, you will need to install the certificate and key on the
server.
 In this case; you will be making a pem certificate.
32

Anatomy of the Application
33

How the Application Works
• Registration
 The application calls the registerForRemoteNotificationTypes:
method.
 The delegate implements the
application:didRegisterForRemoteNotificationsWithDeviceToken:
method to receive the device token.
 It passes the device token to its provider as a non-object, binary
value.
• Notification
 By default this just works based on the payload; for syncing you
would implement this on the launch.
34

Example of Handling Registration
35

Example of Handling Remote Notification
36

Implementing the Server
• Phew, through the Objective C.
• We will be leveraging APNS-PHP for this example as it
encompasses everything you will need to be able to send
notifications.
• http://code.google.com/p/apns-php/
37

How the Server Works
38

Example APNS-PHP Server
39

Example APNS-PHP Feedback Loop
40

Microsoft Push Notifications
Well, I am not certain if they will find the market share yet
but hey; some people need to build apps for it!

Understanding MPNS
• It allows third-party application servers to send lightweight
messages to their Windows Mobile applications.
• Microsoft makes no guarantees about delivery or the order of
messages. (See a pattern yet?)
• 3 types of messages: Tile, Toast or Raw
• Limitations:
 One push channel per app, 30 push channels per device, additional
adherence in order to send messages
 3K Payload, 1K Header
• http://msdn.microsoft.com/en-us/library/ff402537.aspx
42

Preparing to Implement MPNS
• Upload a TLS certificate to Windows Marketplace
 The Key-Usage value of the TLS certificate must be set to include
client authentication.
 The Root Certificate Authority (CA) of the certificate must be one
of the CAs listed at: SSL Root Certificates for Windows Phone.
 Stays authenticated for 4 months.
 Set Service Name to the Common Name (CN) found in the
certificate's Subject value.
 Install the TLS certificate on your web service and enable HTTP
client authentication.
• We will be using the following PHP class for this:
http://phpwindowsphonepush.codeplex.com/
43  Certainly not the most beautiful code but it works.

Anatomy of MPNS
44

Registering for Push
45

Implementing the Callbacks for Notifications
46

Implementing the Server
• Real easy, real fast and a simple class…
 I’m not too fond on the code to repeat myself but it would be easy
to clean up 
 http://phpwindowsphonepush.codeplex.com/
• Pretty much nothing else left to do but show you the
options!
47

Example Implementing MPNS w/ PHP
48

BlackBerry Push Notifications
Are these even going to be needed in another year?

Understanding BlackBerry Push
• It allows third-party application servers to send lightweight
messages to their BlackBerry applications.
• Allows a whopping 8K or the payload
• Uses WAP PAP 2.2 as the protocol
• Mileage may vary…
 Only a sample php push server has ever been published.
 Looks to be mainly for the Browser: http://bit.ly/fYl6rr
50

Anatomy of BB Push
51

Application Code
• They have a “Sample” but it is deep within their Push SDK.
Many of which are pre-compiled.
 Documentation is hard to follow and the sample isn’t exactly
straight forward:
• Install the SDK then go to BPSS/pushsdk-low-level/sample-push-
enabled-app/ and unzip sample-push-enabled-app-1.1.0.16-sources.jar
• You will see several areas to get the push notifications going… Let’s
take a look.
52

Preparing to Implement
• You need to register with BlackBerry and have all of the
application details ready to go:
 https://www.blackberry.com/profile/?eventId=8121
• Download the PHP library:
 Updated to be OO; non-tested and a bit sloppy:
https://github.com/mwillbanks/BlackBerryPush
 Original source: http://bit.ly/nfbHXp
53

Implementing BB Push w/ PHP
• Be aware… this code is highly alpha – never been tested.
• Let me know how it goes… Will be refactoring it and testing
it in the future.
54

Moving Forward
• ZF 2
 I am looking as time permits to contribute implementations of the
4 big players push notification implementations to Zend
Framework. I am not sure when I will find the time but at some
point…
• BlackBerry
 Who knows where they will end up. All I know is that developing
for it seems painful and the documentation is certainly not what I
would like to see.
 There is a large need for a quality implementation but at the same
point developers are not highly interested in their platform.
55

Resources
• Main Sites
 Apple Push Notifications:
http://developer.apple.com/library/ios/#documentation/NetworkingInternet/Con
ceptual/RemoteNotificationsPG/Introduction/Introduction.html
 Google C2DM (Android): http://code.google.com/android/c2dm/
 Microsoft Push Notifications: http://msdn.microsoft.com/en-
us/library/ff402558(v=vs.92).aspx
 BlackBerry Push Notifications:
http://us.blackberry.com/developers/platform/pushapi.jsp
• Push Clients:
 Apns-php: http://code.google.com/p/apns-php/
 ZF C2DM: https://github.com/mwillbanks/Zend_Service_Google_C2dm
 MS: http://phpwindowsphonepush.codeplex.com/
 BlackBerry: https://github.com/mwillbanks/BlackBerryPush
• Might be broken but at least better than what I found anywhere else 
56

Questions?
Give me feedback: http://joind.in/3766
Slides will be posted at joind.in later this afternoon.