Multipeer Connectivity Framework - Lost Peer stays in Session

Question

I wonder if this Multipeer Connectivity framework is ready for use in the real world, given all the bugs that have been encountered by the community. I think I\'m setting it

Answer 1

My only workaround to this type of issue has been to have a 1-1 relationship between sessions and peers. It complicates the sending of broadcasts, but at least allows for peer-level disconnects and cleanup through disconnecting/removing the session itself.

Update

To elaborate on my original answer, in order to be able to send data to connected peers it's necessary to maintain a reference to the session that was created for each peer. I've been using a mutable dictionary for this.

Once the invitation has been sent/accepted with a new session, use the MCSession delegate method to update the dictionary:

- (void)session:(MCSession *)session peer:(MCPeerID *)peerID didChangeState:(MCSessionState)state {

    if (state==MCSessionStateConnected){

        _myPeerSessions[peerID.displayName] = session;

    }
    else if (state==MCSessionStateNotConnected){

        //This is where the session can be disconnected without
        //affecting other peers
        [session disconnect];            

        [_myPeerSessions removeObjectForKey:peerID.displayName];
    }
}

All peers can be accessed with a method that returns all values of the dictionary, and in turn all connectedPeers (in this case one) for each MCSession:

- (NSArray *)allConnectedPeers {

   return [[_myPeerSessions allValues] valueForKey:@"connectedPeers"];

}

Sending data to a particular peer or via broadcast can be done with a method like this:

- (void)sendData:(NSData *)data toPeerIDs:(NSArray *)remotePeers reliable:(BOOL)reliable error:(NSError *__autoreleasing *)error {

    MCSessionSendDataMode mode = (reliable) ? MCSessionSendDataReliable : MCSessionSendDataUnreliable;

    for (MCPeerID *peer in remotePeers){

       NSError __autoreleasing *currentError = nil;

       MCSession *session = _myPeerSessions[peer.displayName];
       [session sendData:data toPeers:session.connectedPeers withMode:mode error:currentError];

       if (currentError && !error)
        *error = *currentError;
    }
}