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I'm trying to implement my C# backend's communication with Notification Hub. I've read almost every tutorial about Azure Notification Hub, and I can't find a decent tutorial that explains what actually corresponds to what. I think there are two ways of representing a device (from what I've understood): an Installation and Registration, and Installation seems to be newer and more preferred.

However, when I get into Installation, I get more questions in my mind:

What is InstallationId? Is it something that I create, or something that I get from somewhere, either device or PNS.

Do I need to set up ExpirationTime, or does it default to longest (it says 90 days is the longest)? What if I want it to be longer than 90 days?

What is PushChannel? Is it, just like InstallationId, something that I create, or get from somewhere?

How are templates exactly used?

Out of all these variables, which one is the actual device push token that I get at the client?

I usually don't ask those kind of questions that seek for a tutorial-ish answers and have multiple questions, but I've tried to search everywhere, but the more I search, the more it gets complicated and I don't even know where to start. Any answer would be a good starting point to anyone trying to learn Notification Hubs, just like me.

Can Poyrazoğlu
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  • As you may know there are 2 models - registration and installation by which your device is mapped to notification hub. InstallationId uniquely identifies an installation. the whole mapping model is referred to as installation. Pushchannel is a the push notification channel URI associated with the given installation. it is issued by Windows Push Notification Services (WNS). installation must be updated on app startup where expiration time is a property. default max is 90. one option is to update TTL of notification hub instead bit .ly/2efugEB – Aravind Oct 24 '16 at 10:00
  • @Aravind which property is the actual push token then? – Can Poyrazoğlu Oct 24 '16 at 11:30
  • when an app is registered, app identifier and security token( APNS device token in IOS or GCM registration id in android) are provided. This is the token to be sent. Whereas authorization at the notification hubs is via SAS tokens to control various permissions. – Aravind Oct 24 '16 at 11:46
  • @Aravind yes I have the token. But where do I send it? Which variable in an `Installation` object corresponds to the token? (I already have the token) – Can Poyrazoğlu Oct 24 '16 at 12:15
  • PushChannel corresponds to the token. See https://msdn.microsoft.com/library/azure/microsoft.azure.notificationhubs.installation_properties.aspx?f=255&MSPPError=-2147217396 for more details – Mimi Xu Oct 24 '16 at 17:40
  • The two models for registering devices, the ones @Aravind refers to, are described [here](https://msdn.microsoft.com/en-us/magazine/dn948105.aspx) – Pynchia Mar 20 '18 at 14:07

2 Answers2

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InstallationId is an abstraction on top of device token/key/channel etc. It's a unique id that you create when you 'install' a device (or user if your OS/platform allows separate tokens for multiple users). This is an id you can use to associate tags, templates etc with the device. You create an installation once and then keep the id somewhere in the local storage and then make updates to the installation associated with the id if you need to.

You don't need to explicitly set ExpirationDate. I think in the past tokens on most platforms used to expire, so this was a way to let Notification Hubs know when not to try to push to the token. I believe now it's not the case. So what happens is if Notification Hubs cannot deliver a notification to a device for a number of times, it just deletes the registration by itself.

Has this post on templates been useful?

PushChannel stands for 'The channel URI if registering the installation for WNS; Device Token if registering for APNS.'

Let me know in the comments if I can clarify any of these and I'll update the answer.

Nikita R.
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There is actually a 3rd option besides Installation and Notification: DirectSend.

The Direct-Send technique is less of an abstraction than Installation and Notification. With Direct-Send you can send notifications directly to one or more specific devices. Basically you use the actual deviceToken- as in what @NikitaG notes for PushChannel.

If you need to be able to decide specifically when your back-end application pushes to a specific-device-A-but-not-B vs. pushing to a specific-device-B-but-not-A vs. specific-device-A-and-specific-device-B according to some schedule Direct-Send can be enabling.

I'd listed some of the resources discussing Direct-Send at Azure Notification Hubs Send Notification to Specific Device.

Pynchia
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Howard Hoffman
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