Re: [Linphone-users] Problem with app for IOS

[Daniel-Constantin Mierla]

Just to throw my 2c here, not being a mobile app developer, but i did at some point in time a bit of googling on this matter.

The issue is how apple/google decided to allow push notifications to an app, respectively can be done only by the "developer" of that app. By "developer" you must understand "who published the app on their store", not the one who wrote the code for it.

So, for someone that uses its own sip server and wants to get push notifications on linphone, they have to:

  - register as a developer to apple/google and obtain a developer (crypto) certificate
  - build linphone by themselves (likely will require a different app name) and sign the app with their developer certificate
  - deploy the custom linphone built app to the apple/google store
  - get their sip users use the custom linphone app

After that, your SIP server can send push notification to your custom linphone app, as you send push notifications using your developer certificate.

Again, all these are based on some research I did a while ago (more than one year).

Not sure if someone already thought of it (didn't search the web for it yet), or even if it is possible, but at that time my idea to deal with these constraints and not build lots of apps myself (e.g., for email, sip, etc...) was write a simple application that can be built easily by anyone and deployed in A/G stores.

This app should have some configuration mechanism that would allow to specify the apps to be waken up based on push notification payload. My doubt about being possible or not is more about the ability of those extra apps to be waken up by another app and behave as expected, so maybe those apps would also need a local "push notification" interface.

Cheers,
Daniel

On 09.07.18 14:11, Greg Troxel wrote:

Benjamin Reis <address@hidden> writes:

The push notifications has to go through Apple/Google since the server only makes a request to for push notification to the Apple/Google servers.

For now push notifications only works with sip.linphone.org
<http://sip.linphone.org/> accounts on Linphone, we are searching for
a way to expand it to all services but for now it’s not possible.

I am puzzled by "not possible", particularly in the context of open
source.  If you mean that the code for this is not known to exist in
other SIP server implementations, or in clients other than linphone,
that's certaily understandable.  I would expect that each client and
each server codebase requires extending to support this switch-to-push
mode.

It seems there must be some extension to SIP where a client can inform
the server that it's going to switch to push mode, where the server ends
up with a token to use with APNS/GCM, and the client stops actively
registering (e.g., closes the TCP connection), but the server considers
it registered.  Then, when there is traffic for the client, a wakeup is
sent, and the client connects again, and things proceed normally.

After writing that, I searched a bit and indeed there is a protocol
specification:

  https://datatracker.ietf.org/doc/draft-ietf-sipcore-sip-push/

Is linphone client and server using the soon-to-be Proposed Standard?

To sort of answer Juha's question, the IETF draft says that the push
notification cannot have a payload, and causes the client to send a new
REGISTER.  So presumably push providers can tell that a device is using
a particular SIP server by observing where the incoming push requests
come from, but it does not appear to leak contact information.

So another question is whether linphone's mechanism is sending any
content in the push messages.

Thanks,
Greg

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Daniel-Constantin Mierla -- www.asipto.com
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