We have implemented a system to upload our MP3 podcasts to SoundCloud on a regular basis by using Java SoundCloud API library. Everything works great in 99% of the time.
However, we've had a couple of occasions when a worker thread, which runs periodically every couple of minutes, and whose job is to upload new podcasts (if any) simply gets "stuck" and never finishes the execution, although the code is wrapped with exception catching blocks, no exception ever gets thrown. This stops the execution of any consecutive such thread and the server has to be restarted in order to regain the functionality.
The code used for obtaining access token seems to be the only place where the problem can occur since we were not uploading a podcast at the time when the problems occurred.
When the problem happened we were asking for the token every time the job run (even though there were no podcasts to upload), so we changed that now so we ask for the token only when we upload a podcast (once a week) and it's less likely we will have the same situation again, but we were wondering is this something you've heard about before, and if there is something we can do to avoid this kind of situations? Thank you.
I'll be happy to provide any additional information, if needed.
Related
I've run into some weird issues with libSpotify. It seems that any libSpotify-based client will take ages to process requests (sometimes 20 seconds for a simple search, seconds for loading one single image, etc..) sent to Spotify servers, whereas Spotify's own desktop client for Windows works extremely well on the same system, processing requests and loading images in near realtime.
Even the demo app provided with libSpotify, called spshell, exhibits massive problems:
Did anyone experience similar problems and/or knows the cause?
Magically works again since today, no clue why.
I'm not really sure what's going on, but today I've noticed that the facebook api is working extremely slow for me.
At first I though it was a bug in my code, but I tried the Graph API Explorer, and even that's causing timeout errors half the time (just using /me):
Failed to load resource: the server responded with a status of 504 (Server timeout)
I don't think its my internet connection, since everything else seems to be working quickly, and http://speedtest.net is giving me good results.
Is my problem somehow fixable or is this just some sort of freak occurance?
Has this happened for anyone else?
Do I need to consider the case that it will take exceedingly long in my application to recieve a response?
I currently have a registration page that waits for a FB.api response (with a spinner gif) before displaying the form. I could use a timeout to wait a few seconds and show it if the api doesn't respond, but I'd really rather not have to use this same sort of logic in every api call that my application depends on...
EDIT: its spontaneously fixed itself now. still no clue what happened.
You can check facebook api live status with this URL
https://developers.facebook.com/live_status
today at 11:13pm: API issues We're currently experiencing a problem
that may result in high API latency and timeouts. We are working on a
fix now.
I've decided to integrate OpenFeint into my new game to have achievements and leaderboards.
The game is dynamic and I would like user to be rewarded immediately for some successful results, but as it seems for me, OpenFeint's achievements are a bit sluggish and it shows visual notification only when it receives confirmation from the server.
Is it possible to change something in settings or hack it a little bit to show notification immediately as soon as it checks only local database if the achievement has not been unlocked it?
Not sure if this relates to the Android version of the SDK (which seems even slower), but we couldn't figure out how to make it faster. It was so unacceptably slow that we started developing our own framework that fixes most of open feint's shortcomings and then some. Check out Swarm, it might fit your needs better.
There are several things you can do to more tightly control the timing of these notifications. I'll explain one approach and you can use this as a starting point to explore further on your own. These suggestions apply specifically to iOS apps. One caveat is that these suggestions refer to internal APIs in OFSDK 2.8 for iOS and not ordinarily recommended for high level use and subject to change in future versions.
The first thing I recommend is that you build the sample app with your own product key. Use the standard sample app to experiment before applying the result to your own code.
You are going to get the snappiest response by separating the notification pop-up UI from the process of submitting the achievement. This way you don't have to worry about getting wrapped up in the logic for deciding whether the submission is going just to the local db or is doing the full confirmation on an async network transaction.
See the declaration of "showAchievementNotice" in "OFNotification.h". Performing a search in the sample app, you will see that this is the internal API used for displaying the achievement pop-up when an achievement is earned. It does not actually submit the achievement. You can call this method directly as it is called from "OFAchievementService.mm" to directly control when the message appears. You can then use the following article to disable the pop-up from being called when the actual submission occurs:
http://support.openfeint.com/dev/notification-pop-ups-in-ios/
This gives you complete freedom to call the submission at a later time provided you keep track of the need to do so. For example, you could locally serialize a flag to take care of the actual submission either after the level is done or the next time the app starts up. Don't forget that the user could quit out of a game without cleanly finishing a level.
My iPhone application supports a proprietary network protocol using the CocoaAsyncSocket library. I need to be able to send a network message out when my iPhone application is closed. The code that sends the message is getting called from the app delegate, but the application shuts down before the message actually goes out. Is there a way to keep the application alive long enough for the message to go out?
Bruce
The docs from Apple don't specifically state this, but the sense I get from looking around the Web and from personal experience is that you have about 4 to 5 seconds after the user hits the Home button to shut your app before your application actually terminates. The iPhone OS is controlling this so you can't block the termination to allow your program to finish first. Basically when your time is up, your program is killed.
There may be another solution, though. First I'd confirm that your code is really taking more than 5 seconds to run. Perhaps you can have it run in response to a button tap, and time how long it runs. If it is more than 5 seconds, you probably are running into this time out issue.
You might then find a way to trigger a message to be sent from a server that is always running. You should have enough time to trigger a remote action, which in turn could then take as long as it needs to run.
Or perhaps you could save the vital information to the iPhone file system on exit, and send that message the next time someone starts the application, which should theoretically give you enough time.
Hope this helps!
I assume you're already calling it from your AppDelegate's:
- (void)applicationWillTerminate:(UIApplication *)application
But as you've discovered there's no guarantee it'll be called or will be allowed to finish. There are a few options that may or may not work depending on what you're trying to do:
If you need the server to perform some sort of cleaning operation triggered by when the client app is gone then you could try watching for TCP socket closure on the server and treating that as the triggering event. But if you explicitly need to send data back with the closure this may not work.
If the data you're sending back is not time-sensitive then you can do like most of the analytics libraries do and cache the data (along with a uuid) on the client then try to send it on app closure. If it goes through, you can clear the cache (or do it the next time the app is run). If it doesn't, it's saved and you can send out when the app is run next. On the server, you would use the uuid to avoid duplicate requests.
If the material is time-sensitive then your best bet is to implement heartbeat and send periodic updated values to the server. Then when the client app dies the server times out the heartbeat and can use the last received value as the final closing point of data.
In either case, if an explicit closure event is required by your custom protocol then you may want to reconsider using it in a real-life mobile environment where things have to be much more fluid and tolerant of failure.
As others have noted, there's no way to be absolutely certain that you'll be able to send this, but there are approaches to help.
As Ken notes, you do in practice get a few seconds between "willTerminate" and forced termination, so there generally is time to do what you need.
A problem you're almost certainly running into is with CocoaAsyncSocket. When you get the "willTerminate" message, you're on the last run loop of the main thread. So if you block the main thread, and CocoaAsyncSocket is running on the main thread, it'll never get processed. As I recall, CocoaAsyncSocket won't actually send all the data until the next event loop.
One approach, therefore, is to keep pumping the event loop yourself:
- (void)applicationWillTerminate:(UIApplication *)application
{
// ...Send your message with CocoaAsyncSocket...
while (! ...test to see if it sent...)
{
[[NSRunLoop currentRunLoop] runMode:NSDefaultRunLoopMode beforeDate:[NSDate distantFuture]];
}
}
I've also looked at putting this work onto a background thread and letting the main thread terminate, in theory letting us go back to Springboard while continuing to run for a few seconds. It's not immediately clear to me whether this will work properly using NSThread (which are detached). Using POSIX threads (which are joinable by default) may work, but probably circumvents any advantages of the background thread. Anyway, it's something to look at if useful. In my apps, we've used the "post next time we launch" approach, since that always works (even if you crash).
I have a web application that I am adding workflow functionality to using Windows Workflow Foundation. I have based my solution around K. Scott Allen's Orders Workflow example on OdeToCode. At the start I didn't realise the significance of the caveat "if you use Delay activities with and configure active timers for the manual scheduling service, these events will happen on a background thread that is not associated with an HTTP request". I now need to use Delay activities and it doesn't work as is with his solution architecture. Has anyone come across this and found a good solution to this? The example is linked to from a lot of places but I haven't seen anyone else come across this issue and it seems like a bit of a show stopper to me.
Edit: The problem is that the results from the workflow are returned to the the web application via HttpContext. I am using the ManualWorkflowSchedulerService with the useActiveTimers and this works fine for most situations because workflow events are fired from the web app and HttpContext still exists when the workflow results are returned and the web app can continue processing. When a delay activity is used processing happens on a background thread and when it tries to return results to the web app, there is no valid HttpContext (because there has been no Http Request), so further processing fails. That is, the webapp is trying to process the workflow results but there has been no http request.
I think I need to do all post Delay activity processing within the workflow rather than handing off to the web app.
Cheers.
You didn't describe the problem you are having. But maybe this is of some help.
You can use the ManualWorkflowSchedulerService with the useActiveTimers and the workflow will continue on another thread. Normally this is fine because your HTTP request has already finished and it doesn't really matter.
If however you need full control the workflow runtime will let you get a handle on all loaded workflows using the GetLoadedWorkflows() function. This will return acollection of WorkflowInstance objects. usign these you can can call the GetWorkflowNextTimerExpiration() to check which is expired. If one is you can manually resume it. In this case you want to use the ManualWorkflowSchedulerService with the useActiveTimers=false so you can control the last thread as well. However in most cases using useActiveTimers=true works perfectly well.