Data parameter is nil ( on authorize presence channel )

[Reizar]

Hi,

I'm getting this error when I try to subscribe to my presence channel:

*** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: 'data parameter is nil'
*** First throw call stack:
(
    0   CoreFoundation                      0x0000000102eef795 __exceptionPreprocess + 165
    1   libobjc.A.dylib                     0x0000000102a9d991 objc_exception_throw + 43
    2   CoreFoundation                      0x0000000102eef5ad +[NSException raise:format:] + 205
    3   Foundation                          0x00000001027784a8 +[NSJSONSerialization JSONObjectWithData:options:error:] + 67
    4   LocalChat                           0x00000001000ecb81 -[PTNSJSONParser objectFromJSONData:] + 81
    5   LocalChat                           0x00000001000ecc39 -[PTNSJSONParser objectFromJSONString:] + 121
    6   LocalChat                           0x00000001000f4651 -[PTPusherPresenceChannel subscribeWithAuthorization:] + 177
    7   LocalChat                           0x00000001000ee686 __31-[PTPusher subscribeToChannel:]_block_invoke + 246
    8   LocalChat                           0x00000001000f3716 __57-[PTPusherPrivateChannel authorizeWithCompletionHandler:]_block_invoke + 198
    9   LocalChat                           0x00000001000f6e55 -[PTPusherChannelAuthorizationOperation finish] + 1509
    10  LocalChat                           0x00000001000fb55b -[PTURLRequestOperation connectionDidFinishLoading:] + 91
    11  Foundation                          0x000000010278ee9b __65-[NSURLConnectionInternal _withConnectionAndDelegate:onlyActive:]_block_invoke + 48
    12  Foundation                          0x00000001026426ab -[NSURLConnectionInternal _withConnectionAndDelegate:onlyActive:] + 210
    13  Foundation                          0x00000001026425bc -[NSURLConnectionInternal _withActiveConnectionAndDelegate:] + 69
    14  CFNetwork                           0x0000000100c44777 ___ZN27URLConnectionClient_Classic26_delegate_didFinishLoadingEU13block_pointerFvvE_block_invoke + 107
    15  CFNetwork                           0x0000000100c42942 ___ZN27URLConnectionClient_Classic18_withDelegateAsyncEPKcU13block_pointerFvP16_CFURLConnectionPK33CFURLConnectionClientCurrent_VMaxE_block_invoke_2 + 84
    16  CFNetwork                           0x0000000100c85f74 ___ZNK17CoreSchedulingSet13_performAsyncEPKcU13block_pointerFvvE_block_invoke + 25
    17  CoreFoundation                      0x0000000102e96114 CFArrayApplyFunction + 68
    18  CFNetwork                           0x0000000100bb5beb _ZN19RunloopBlockContext7performEv + 115
    19  CFNetwork                           0x0000000100bb5a31 _ZN17MultiplexerSource7performEv + 247
    20  CFNetwork                           0x0000000100bb5854 _ZN17MultiplexerSource8_performEPv + 72
    21  CoreFoundation                      0x0000000102e7eec1 __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ + 17
    22  CoreFoundation                      0x0000000102e7e792 __CFRunLoopDoSources0 + 242
    23  CoreFoundation                      0x0000000102e9a61f __CFRunLoopRun + 767
    24  CoreFoundation                      0x0000000102e99f33 CFRunLoopRunSpecific + 467
    25  GraphicsServices                    0x0000000103d843a0 GSEventRunModal + 161
    26  UIKit                               0x0000000101700043 UIApplicationMain + 1010
    27  LocalChat                           0x00000001000158d3 main + 115
    28  libdyld.dylib                       0x00000001035675fd start + 1
    29  ???                                 0x0000000000000001 0x0 + 1
)
libc++abi.dylib: terminating with uncaught exception of type NSException

I am using libpusher 1.5, installed via CocoaPods. Using ios7 and xCode5

I'm subscribing to the channel with this code:

[self.client subscribeToPresenceChannelNamed:self.place.objectId delegate:self];

This is what the auth function on my backend returns. ( the auth function is being invoked )

{"auth":"69c920ed28e119bb585e:60401bfab73d568110adb64d3c181b77edc05af26c5547b725417e03ce06d641","channel_data":"{\"user_id\":\"odRhbWC745\",\"user_info\":{\"username\":\"test\",\"avatarURL\":\"http://files.parse.com/ee5174bf-3d50-49b8-88b8-2466a133600a/89d23b41-9a5d-474e-9a71-6bf7034f8b16-file\",\"displayName\":\"test\"}}"}

Regular public channel subscriptions work fine, as do their binded events. Just seems to be obtaining the auth data thats crashing it.

[Reizar]

Been looking through the code and trying to debug this issue.

So it seems the authData that gets used in PTPusherPresenceChannel had a nesting that messed up some of the dictionary keys.

I changed

- (void)subscribeWithAuthorization:(NSDictionary *)authData
{

  [super subscribeWithAuthorization:authData];

  NSDictionary *channelData = [[PTJSON JSONParser] objectFromJSONString:authData[@"channel_data"]];

  self.members.myID = channelData[@"user_id"];
}

To this:

- (void)subscribeWithAuthorization:(NSDictionary *)authData
{

  [super subscribeWithAuthorization:authData];

  NSDictionary *channelData = [[PTJSON JSONParser] objectFromJSONString:authData[@"result"][@"channel_data"]];

  self.members.myID = channelData[@"user_id"];
}

( result was a top level key, not sure where it came from as my backend doesn't have this )

This has stopped my app from crashing, however it doesn't seem like the presence channel is actually subscribing as no delegate methods are being called. ( the delegate has been set )

• (void)pusher:(PTPusher *)pusher didFailToSubscribeToChannel:(PTPusherChannel *)channel withError:(NSError *)error

is not being called either at the moment.

[lukeredpath]

You need to find out where this result key is coming from. It must be coming from your server. Can you post the full HTTP response from your server?

[Reizar]

You're right. I'm using Parse as my backend and they nest the response under a result key. I've gotten that fixed up.

Looks like there was also a problem with my auth function on my backend which is why it wasn't connecting. Its all working now :)

Thanks :)