How does server locate GCM (Google Cloud Messaging) registration IDs

Question

I am trying to write an application which notifies a cellphone using GCM. I was able to implement basic functionality, but there is one question I'm still unsure of

As I understand, the flow goes like this:

1. Device start up
2. Device registers, obtains registration id
3. Server gets the knowledge of registration id on device
4. Server is using it's API key + registration id to send payload to device
5. Device receives payload.

One thing which is unclear to me is: what is a proper methodology to implement step #3?

I could not find any way to obtain a list of registered devices. Lets imagine, I am using GCM for a purpose of posting to a known device, and I could email that ID to myself and then register it on the server manually. But as I understand, it expires.

So, it there an expectation that I have to keep re-registering and somehow notifying server every time it happens?

Answer 1

Yes, your app on device must send registration ID to your server application in order for server to be able to send GCM messages. See third point in Enabling GCM.