multipeer | Pythonista class for iOS multipeer connectivity

You are probably being unable to cause a renegotiaton so change to the facingMode of your camera cannot affect the other peers, but you do not use this explicitely as I see but replaceTracks. But still you may not being able to trigger a renegotiation. Checkout things that cause renegotiation: https://developer.mozilla.org/en-US/docs/Web/API/RTCRtpSender/replaceTrack#Usage_notes

Changing facingMode setting by applying constraints with applyConstraints may be a solution without using replaceTracks.

A strange idea coming to my mind to dispatch negotiationneeded event yourself, but I would try this after chasing the reason not being able to casue renegotiation itself by replacing track, or changing camera, and everything else.

About another reason: As for the reasons that casues renegotiation, your back camera resolution is most probably higher than the front camera, so it looks like a reason. If you start from the back camera first and then switch to front it might have been a no reason. I am suspicious about your max constraints of width nad height. They might be very lower for the both camera hence resulting in the same size, resoltion and so a no reason according to the list in the linked page above. I suggest removing them.

Also the replaceTracks returns a promise but the map function it is called from does not return anything, hence undefined. You are supposed to use the promises inside the array argument to Promise.all. I would suggest return those promises inside the map function.

I'll go with a solution based on NWConnection which uses NWEndpoint and can be created with both IP:port and a Bonjour-established service.

If I would've had access to the full Network.framework then I could've used that for both discovery & communication but due to SDK constraints I'll be using MultipeerConnectivity for the discovery aspect instead. By providing the device its IP & port when broadcasting the Bonjour service, another device can discover it automatically and then use the extra info to create an IP:port-based NWConnection.

Paths should be set using the full path /home/user/yourPath instead of the shortcut ~/yourPath.

Anyway, remember always to check the app logs and not just the console since sometimes they show much more information.

It seems MCAdvertiserAssistant and MCBrowserViewController are not updated for latest versions of iOS & Swift, hence they're not working properly.

I solved it by using MCNearbyServiceAdvertiser instead of MCAdvertiserAssistant and MCNearbyServiceBrowser instead of MCBrowserViewController. Note that by using these classes, you'll need to perform basic operations yourself such as listing founded devices, showing and handling invitation alert.. etc.

You can use these classes as below.

Definition:

There are a couple issues here as far as I can tell.

First, I would suggest you try this with your MPCManager:

When user declines the invitation the device that initiated the invite will get a delegate state change with state = MCSessionStateNotConnected.

As far as I know this state will also happen if user fails to connect for some reason, but you could distinguish the two flows since when connection fails you will also get state change first to MCSessionStateConnecting and then to MCSessionStateNotConnected.

So in short:

1. State change from MCSessionStateConnecting toMCSessionStateNotConnected means device failed to connect but invite was accepted
2. State only goes to MCSessionStateConnecting, means user tapped decline

Given that you need advanced logic when a game can be started you will not be able to rely on the built in MCBrowserViewController since this will have Done button enabled as soon as one of the peers is coonected.

You would have to use MCNearbyServiceBrowser then you initiate each invite with -invitePeer:toSession:withContext:timeout: and thus you have a way of knowing who was invited, and based on delegate calls who connected, who failed to connect or who declined.

Hope this helps...

You can use a helper computed property:

I can think of two solutions: using data contexts or using a second browser

Using data contexts

Use your dummy id but don't rely on its displayName property. Instead pass your real display name via the context parameter of invitePeer(_ peerID: MCPeerID, to session: MCSession, withContext context: Data?, timeout: TimeInterval)

I (finally) figured it out. MultipeerConnectivity needs a run loop. This is not in the documentation.

I assumed that the MultipeerConnectivity API created the threads and/or loops it needed upon the method call [browser startBrowsingForPeers]. It does not.

Nowhere in this code is a run loop started. Also, interestingly enough, using a NSThread directly doesn't start a run loop, even though it's implied that it will:

Your application neither creates or explicitly manages NSRunLoop objects. Each NSThread object—including the application’s main thread—has an NSRunLoop object automatically created for it as needed. If you need to access the current thread’s run loop, you do so with the class method currentRunLoop.

What will create a run loop (and start it) is CFRunLoopRun():

The current thread’s run loop runs in the default mode (see Default Run Loop Mode) until the run loop is stopped with CFRunLoopStop or all the sources and timers are removed from the default run loop mode.

What will stop it, then, is CFRunLoopStop(CFRunLoopRef rl):

This function forces rl to stop running and return control to the function that called CFRunLoopRun or CFRunLoopRunInMode for the current run loop activation.

Of course, CFRunLoopStop takes a CFRunLoopRef as an argument. You can get that by using CFRunLoopGetCurrent, just remember it's a reference and may expire at any time. I think you can be pretty sure that the run loop won't die while you're in the callback that's running in the run loop. But I wouldn't count on it sticking around afterwards. In fact, in this case, the whole point is to kill it at this point; so I expect it to go away.