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Can't decode an SFSObject. Byte data is insufficient
Posted: 25 Oct 2012, 18:39
by janheuninck
Hi guys,
Lately we are experiencing a lot of crashes on our client (ios devices, all using the latest SFS API [1.1.1]). When we run the application without attaching it to Xcode, these exceptions seems to be ignored. If we debug in Xcode however, the entire application crashes when the exception occurs. The annoying thing is that this happens very often! Is there a way to put this SFS function between inside a try-catch block to prevent the application from crashing and show a error message instead?
Do you guys also have any idea why this exception occurs?
Thanks!
Code: Select all
2012-10-25 11:13:41.939 ProjectX[34804:707] Uncaught EXCEPTION: Can't decode an SFSObject. Byte data is insufficient. Size: 0 byte(s)
2012-10-25 11:13:41.985 ProjectX[34804:707] Stack Trace: (
0 CoreFoundation 0x35d9e8a7 __exceptionPreprocess + 186
1 libobjc.A.dylib 0x31717259 objc_exception_throw + 32
2 ProjectX 0x00112ef3 -[DefaultSFSDataSerializer binary2object:] + 162
3 ProjectX 0x00127c15 +[SFSObject newFromBinaryData:] + 80
4 ProjectX 0x0012a135 -[SFSProtocolCodec onPacketRead:] + 72
5 ProjectX 0x001265b3 -[SFSIOHandler handlePacketData:] + 890
6 ProjectX 0x00127383 -[SFSIOHandler onDataRead:] + 594
7 ProjectX 0x0013fedb -[UDPManager udpc:didReceiveData:fromAddress:] + 238
8 ProjectX 0x0013ea11 -[UDPController _readData] + 524
9 ProjectX 0x0013ee53 SocketReadCallback + 102
10 CoreFoundation 0x35d752ef __CFSocketPerformV0 + 638
11 CoreFoundation 0x35d72ad3 __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ + 14
12 CoreFoundation 0x35d72335 __CFRunLoopDoSources0 + 364
13 CoreFoundation 0x35d71045 __CFRunLoopRun + 652
14 CoreFoundation 0x35cf44a5 CFRunLoopRunSpecific + 300
15 CoreFoundation 0x35cf436d CFRunLoopRunInMode + 104
16 GraphicsServices 0x35a73439 GSEventRunModal + 136
17 UIKit 0x308cfe7d UIApplicationMain + 1080
18 ProjectX 0x00065903 main + 150
19 ProjectX 0x00065868 start + 40
)
2012-10-25 11:13:41.990 ProjectX[34804:707] *** Terminating app due to uncaught exception 'SFSCodecException', reason: 'Can't decode an SFSObject. Byte data is insufficient. Size: 0 byte(s)'
*** First throw call stack:
(0x35d9e88f 0x31717259 0x112ef3 0x127c15 0x12a135 0x1265b3 0x127383 0x13fedb 0x13ea11 0x13ee53 0x35d752ef 0x35d72ad3 0x35d72335 0x35d71045 0x35cf44a5 0x35cf436d 0x35a73439 0x308cfe7d 0x65903 0x65868)
terminate called throwing an exception(lldb)
Re: Can't decode an SFSObject. Byte data is insufficient
Posted: 25 Oct 2012, 22:47
by A51Integrated
Typically this is cause by the client getting overwhelmed by messages. What happens, is that the SFS server can pound a client with messages and barely feel like it's working, but the client on the other hand, can only handle so much. Depending on how frequently you're sending messages to the client, the size of the messages, and how the client handles them will determine the client message capacity.
Remember, the best connection you'll get on a mobile device is with Wi-Fi, so you're already at a disadvantage in that the network connection is less than optimal. If you send a significant amount of data through that connection, TCP packets may start to get dropped and because they are TCP, they will be sent again until the entire TCP message is received. Most likely, this is what's happening and packets never make it to the client because the network connection is over capacity, experiencing too much lag, or dropping out altogether. You may want to try implementing UDP messages (through extensions) depending on what type of message you're sending. If the information being sent is non-critical, UDP may be a better option since verification of receipt does not occur.
Also, look at your messaging architecture and try and combine data into a single object as apposed to sending multiple messages. This will also reduce the number of messages the client needs to handle.
Re: Can't decode an SFSObject. Byte data is insufficient
Posted: 14 Feb 2013, 06:24
by Fellow
We are still running into the same problem. If we want to catch this error where would we place our try catch blocks?
Is there a way to gracefully catch errors that are thrown by smartfox? Currently our application crashes completly when smartfox throws an error because the exception goes all the way to our main class without being caught higher up.
Thanks
Re: Can't decode an SFSObject. Byte data is insufficient
Posted: 18 Feb 2013, 13:00
by A51Integrated
Let me look into this.
Re: Can't decode an SFSObject. Byte data is insufficient
Posted: 19 Feb 2013, 06:06
by Fellow
Ok thanks. I've reading the documentation as well but I couldn't find anything about catching an exception that is thrown by the smartfox library.
Re: Can't decode an SFSObject. Byte data is insufficient
Posted: 19 Feb 2013, 21:53
by A51Integrated
Have you tried something like:
Code: Select all
#import "SFSCodecException.h"
@try {
// do something that might throw an exception
}
@catch (SFSCodecException *ex) {
// deal with the exception
}
@finally {
// optional block of clean-up code
// executed whether or not an exception occurred
}
Re: Can't decode an SFSObject. Byte data is insufficient
Posted: 20 Feb 2013, 04:45
by Fellow
Well that is just the general try catch structure. The question is more, where do you place that code?
Is the main the only place where you can catch that error? Isn't it too late then already?
Re: Can't decode an SFSObject. Byte data is insufficient
Posted: 20 Feb 2013, 15:27
by A51Integrated
Try it in your main around the SmartFox2XClient instance and let me know. Although I think you may be right. By the time the exception is thrown, it would have killed the chance of capturing the event outside of the API.
Let me do some tests on this end and see what I can find.
Re: Can't decode an SFSObject. Byte data is insufficient
Posted: 20 Feb 2013, 16:05
by A51Integrated
OK. From Apple:
http://developer.apple.com/library/ios/ ... 009045-SW1
The Cocoa frameworks are generally not exception-safe. The general pattern is that exceptions are reserved for programmer error only, and the program catching such an exception should quit soon afterwards.
So in theory, when an exception is thrown like this, the app should quit (which it does). Catching these errors and continuing may cause undesirable affects. However, there is a way to catch the error from the Main class, the trick is to not quit the application.
Code: Select all
#import <UIKit/UIKit.h>
#import "SFSCodecException.h"
int main(int argc, char *argv[]) {
NSAutoreleasePool * pool = [[NSAutoreleasePool alloc] init];
int result = 0 ;
@try {
result = UIApplicationMain(argc, argv, nil, nil);
}
@catch (SFSCodecException *ex) {
NSLog(@"%@", ex);
}
@finally {
NSLog(@"This always happens.");
result += 2;
}
[pool release];
return result;
}
Although this is bad practice and I would recommend not to use it.
Re: Can't decode an SFSObject. Byte data is insufficient
Posted: 20 Feb 2013, 19:32
by Fellow
Ok, thanks.
We get that error quiet a lot when we are developing our game and because we use the debug it crashes constantly.
It doesn't crash when we make a release build (just like Apple says in that documentation "reserved for programmer error only").
So I guess there is no solution for this problem since the crashing happens in smartfox.
Re: Can't decode an SFSObject. Byte data is insufficient
Posted: 20 Feb 2013, 19:38
by A51Integrated
It's not really SFS where the error happens - that's where it's thrown. What the API is trying to do is read a packet, and because the packet is incomplete, it throws the exception. So it works as expected.
Re: Can't decode an SFSObject. Byte data is insufficient
Posted: 03 Mar 2013, 05:13
by Fellow
Our QC team is currently testing our app intensively and we are seeing that 85% of the crashes are happening because of an exception thrown by the smartfox library.
We are seeing 2 different types of exceptions:
Type 1: Can't decode an SFSObject. Byte data is insufficient. Size: 0 byte(s)
(happens 40% of the crashes)
Code: Select all
Exception Type: SIGABRT
Exception Codes: #0 at 0x3bfef350
Crashed Thread: 0
Application Specific Information:
*** Terminating app due to uncaught exception 'SFSCodecException', reason: 'Can't decode an SFSObject. Byte data is insufficient. Size: 0 byte(s)'
Last Exception Backtrace:
0 CoreFoundation 0x000c22a3 __exceptionPreprocess + 163
1 libobjc.A.dylib 0x3baf197f _objc_exception_throw + 31
2 MyAPP 0x005f5a2b -[DefaultSFSDataSerializer binary2object:] (DefaultSFSDataSerializer.m:774)
3 MyAPP 0x0060a74d +[SFSObject newFromBinaryData:] (SFSObject.m:41)
4 MyAPP 0x0060cc6d -[SFSProtocolCodec onPacketRead:] (SFSProtocolCodec.m:89)
5 MyAPP 0x006090eb -[SFSIOHandler handlePacketData:] (SFSIOHandler.m:92)
6 MyAPP 0x00609ebb -[SFSIOHandler onDataRead:] (SFSIOHandler.m:234)
7 MyAPP 0x005eaa69 -[BitSwarmClient stream:handleEvent:] (BitSwarmClient.m:479)
8 CoreFoundation 0x0005f7cf _signalEventSync + 75
9 CoreFoundation 0x00065623 _cfstream_solo_signalEventSync + 75
10 CoreFoundation 0x0005f507 _CFStreamSignalEvent + 327
11 CFNetwork 0x000aca8b CoreReadStreamCFStreamSupport::coreStreamReadEvent(__CoreReadStream*, unsigned long) + 99
12 CFNetwork 0x000abc71 CoreReadStreamClient::coreStreamEventsAvailable(unsigned long) + 37
13 CFNetwork 0x000ae365 CoreStreamBase::_callClientNow() + 45
14 CFNetwork 0x000ae0f9 CoreStreamBase::_streamSetEventAndScheduleDelivery(unsigned long, unsigned char) + 89
15 CFNetwork 0x000ae4ff CoreStreamBase::_streamInterface_SignalEvent(unsigned long, CFStreamError const*) + 35
16 CFNetwork 0x00007a15 SocketStream::dispatchSignalFromSocketCallbackUnlocked(SocketStreamSignalHolder*) + 41
17 CFNetwork 0x0001cb57 SocketStream::socketCallback(__CFSocket*, unsigned long, __CFData const*, void const*) + 135
18 CFNetwork 0x0001cab3 SocketStream::_SocketCallBack_stream(__CFSocket*, unsigned long, __CFData const*, void const*, void*) + 75
19 CoreFoundation 0x00099ebb __CFSocketPerformV0 + 699
20 CoreFoundation 0x00097683 __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ + 15
21 CoreFoundation 0x00096ee9 __CFRunLoopDoSources0 + 213
22 CoreFoundation 0x00095cb7 __CFRunLoopRun + 647
23 CoreFoundation 0x33bacebd _CFRunLoopRunSpecific + 357
24 CoreFoundation 0x33bacd49 _CFRunLoopRunInMode + 105
25 GraphicsServices 0x3775f2eb _GSEventRunModal + 75
26 UIKit 0x35ac2301 _UIApplicationMain + 1121
27 MyAPP 0x000038c5 main (main.m:15)
28 libdyld.dylib 0x00001b20 start + 0
(happens 60% of the crashes)
Code: Select all
Exception Type: SIGABRT
Exception Codes: #0 at 0x3bfef350
Crashed Thread: 0
Application Specific Information:
*** Terminating app due to uncaught exception 'SFSException', reason: 'Unexpected header byte: 49'
Last Exception Backtrace:
0 CoreFoundation 0x000c22a3 __exceptionPreprocess + 163
1 libobjc.A.dylib 0x3baf197f _objc_exception_throw + 31
2 MyAPP 0x00609b4b -[SFSIOHandler handleNewPacket:] (SFSIOHandler.m:200)
3 MyAPP 0x00609dfb -[SFSIOHandler onDataRead:] (SFSIOHandler.m:225)
4 MyAPP 0x00622a13 -[UDPManager udpc:didReceiveData:fromAddress:] (UDPManager.m:161)
5 MyAPP 0x00621549 -[UDPController _readData] (UDPController.m:127)
6 MyAPP 0x0062198b SocketReadCallback (UDPController.m:150)
7 CoreFoundation 0x00099ebb __CFSocketPerformV0 + 699
8 CoreFoundation 0x00097683 __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ + 15
9 CoreFoundation 0x00096ee9 __CFRunLoopDoSources0 + 213
10 CoreFoundation 0x00095cb7 __CFRunLoopRun + 647
11 CoreFoundation 0x33bacebd _CFRunLoopRunSpecific + 357
12 CoreFoundation 0x33bacd49 _CFRunLoopRunInMode + 105
13 GraphicsServices 0x3775f2eb _GSEventRunModal + 75
14 UIKit 0x35ac2301 _UIApplicationMain + 1121
15 MyAPP 0x000038c5 main (main.m:15)
16 libdyld.dylib 0x00001b20 start + 0
1. How can we make sure that these errors are not happening anymore? If these exceptions are forcing us to quit the application, we want to know why we are getting these errors.
2. These crashes happen very random and there doesn't seem to be a pattern to make it crash. How can we reproduce these errors? How can we get more information about these exceptions?
3. How can we avoid this crash and what do you suggest that we need to examine and test?
Previous assumption that these crashes only were happening during debugging was false. It also happens in the release builds.
Thanks,
Jonas
PS: Do you provide more in depth support for customers?
Re: Can't decode an SFSObject. Byte data is insufficient
Posted: 03 Mar 2013, 12:36
by A51Integrated
1. How can we make sure that these errors are not happening anymore? If these exceptions are forcing us to quit the application, we want to know why we are getting these errors.
As mentioned above, it's a volume issue. The device simply can't handle the amount of communications back and forth. You're going to have to look into reducing/compressing/optimizing your messages in your app. Think of it like a highway with a serious traffic jam. No matter what you do to your car, it will still be stuck in traffic. You have to reduce traffic in order to travel at 100km/h.
2. These crashes happen very random and there doesn't seem to be a pattern to make it crash. How can we reproduce these errors? How can we get more information about these exceptions?
Because it's related to "overloading" the client, to reproduce, just hammer the client with messages.
3. How can we avoid this crash and what do you suggest that we need to examine and test?
reduce/compress/optimize
Do you provide more in depth support for customers?
Yes. Paid, but in this circumstance I'm not sure you'll benefit from it. Can you describe the structure of your typical messages and how frequently they are being sent/received?
Re: Can't decode an SFSObject. Byte data is insufficient
Posted: 03 Mar 2013, 18:23
by Fellow
Thanks for the quick reply! Great service!
We'll do some testing this week and we'll try to find a scenario where it always crashes.
We'll also give you some more details about how many messages are being sent and what there size are.
Thanks!
Jonas