So, I had a working xamarin forms app that used azure mobile services. I upgraded the server side to use mobile app service and upgraded the nugets in my client to use the latest and greatest client codes.
I manually updated my test/ios simulator sqlite db to use the proper column names for the system properties since they dropped the double underscore prefix.
When I finally got it all built and tried to run in the ios 6/8.3 simulator it ran fine until it hit the InitializeAsync method. It doesn't throw (its in a try catch) and I let it run for a long time and it just sits there.
I then tried to change the db name so it would make it from scratch, which it did but still just hung. So I then tried to simplify it to a single table and took out my delegating handler so it was as basic as I could get it and it still just hangs.
Has anyone else had this problem? I am at a complete loss because I don't get an error. Not sure where to start.
Thanks.
Edit, code added:
var store = new MobileServiceSQLiteStore(_localDatabaseName);
store.DefineTable<Profile>();
try
{
await _mobileService.SyncContext.InitializeAsync(store);
}
catch (Exception e)
{
Debug.WriteLine(e.Message);
}
I also tried with ConfigureAwait(false) as suggested but it made no difference.
I set breakpoints in the catch and the code that immediately follows this block but they are never hit.
Ok, so I poked around a bit more and found some info on deadlocked threads answered by Stephen Cleary, the guru of async/await.
It turned me onto looking upstream. The call into my azure init code looked like this:
var azureService = Container.Get<IAzureService>();
azureService.InitializeAzync().Wait();
Which was in the constructor of the calling component.
So, I changed it to this:
try
{
Task.Run(() => azureService.InitializeAsync()).Wait();
}
catch (Exception ex)
{
Debug.WriteLine(ex.Message);
}
And the SyncContext.InitializeAsync() call worked fine and continued on.
So, I don't really know the answer for this, I guess the internals of the new azure client do something differently than the old code since using Wait() was how I did it before and never had a problem. But there was some sort of threading deadlock. Very odd and took days to get past, now I have to fix the next deadlock I hit. If Stephen is out there and can offer some clarification that would be great.
Had this same issue - changing to a Task.Run and ConfigureAwait(false) did fix it.
Very odd thing is the same code worked fine with Mobile Services, but broke when we upgraded to Mobile App Services.
Related
This is a follow-up from the following question: Having trouble connecting to iSeries from .NET Core
The initial problem was resolved by setting a port number. I'm now running into the problem of the connection seemingly opening, however, hanging on the actual .Open() step - IE, never continuing on to the next line of code. For reference, here's my code block:
public static DB2Connection GetDatabaseConnection(string connectionString)
{
DB2Connection DB2Connection = new DB2Connection(connectionString);
DB2Connection.SystemNaming = true;
try
{
DB2Connection.Open();
return DB2Connection;
}
catch (Exception ex)
{
throw ex;
}
}
And my connection string is in this format: Server=###.###.###.###:#####;Database=DATABASE;UID=USER;PWD=PASSWORD;LibraryList=LIBRARY,LIST
Looking at the logs on the i Navigator, I see that there is a job name Qzhqssrv when is opened, with the user Quser, status Running, and type Prestart batch - Server. Looking into the logs for that entry, I see Job #####/QUSER/QZHQSSRV started on DATE at TIME in subsystem QUSRWRK in QSYS. Job entered system on DATE at TIME. However, it doesn't seem to continue beyond that.
Looking at the logs for a similar operation, when I'm connecting via Access Client Solutions, I get considerably more information and more steps in the logs. This leads me to believe that the system is waiting for me to send further information, however, my application is still stuck on .Open() - so perhaps there is something else I was supposed to send as part of the .Open() instruction. If so, I'm not sure what it would be.
Any insights would be greatly appreciated. Thanks!
Just to close this topic out - the problem was indeed the lack of a license. Connecting on port 446 was the correct approach, and once we got a license, we were able to get the connection working. Thanks #nfgl!
I have made a Blazor app, which is working well locally. When I put it on the server, quite often (when app uses DB context) I get this error :
Error: Connection disconnected with error 'Error: WebSocket closed with status code: 1006 ()
The user have to refresh the page, which is really annoying. You can't use app working in this way.
I have found a lot of discussions on this error, lot of plans...and almost everything is older than one year. I would expect the solution already, but haven't found anything.
Anyone knows, why is this happening and how to figure it out in the Blazor app? At least to catch this error and wait until the connection is back, so the page is not getting faded?
So far I was able to do only automatic reloading of page by javascript, when I get this error. But anyway, I can't use this solution in production, because the page is down for a second and it doesn't look good. I need to catch it before and keep the page active.
Thank you.
FYI , Have you check somewhere on the server-side like the logic that use data from DB context or the security/config in the production between IIS server and DB? If you are sure that it's come from the DB context then have you validate by test other possibility like make the test method that have long delay time/or mockup method that return the data to check whether the error still occur?
I once have a really stupid code in an object. but the code is build with no error. But it clash on runtime with no clue relate to the problem.
private string _oh;
public string oh
{
get { return _oh; }
set { oh= value; // cause infinite loop > should _oh
}
}
The worst part is that the error throwed is the same message as this question, So I quite sure there is the root clause elsewhere.
Error: Connection disconnected with error 'Error: WebSocket closed with status code: 1006 ()
Looking for some clarification as to how one can log caught exceptions using flutter's firebase_crashlytics package.
If I understand correctly (and from running some sample code) Crashlytics.instance.log('text'); will only add logs to the next crash report, rather than send off a non-fatal issue itself.
I'm looking for functionality which is equivalent to Crashlytics.logException(e); on Android, e.g.
try {
throwException();
} catch (e) {
Crashlytics.logException(e);
}
which allows you to log caught exceptions so they appear as non-fatal issues in the Crashlytics dashboard.
Is this currently possible with flutter's firebase_crashlytics package?
Is calling Crashlytics.instance.recordError('text', StackTrace.current) the way to achieve this for now?
Many thanks!
Short answer, yes.
Crashlytics.instance.recordError() is the equivalent of Crashlytics.logException()
If you dig into the Flutter firebase_crashlytics source code, you can actually see what Android APIs are involved.
Flutter’s recordError() invokes the method Crashlytics#onError in the Android library.
And tracing Crashlytics#onError, you’ll see that it goes to Crashlytics.logException(exception);
Additional note, you’ll also notice why Crashlytics.instance.log() ”will only add logs to the next crash report”. These logs are added to a ListQueue<String> _logs which is then packaged into the next call of recordError()
A snippet of Flutter’s invocation of Crashlytics.logException():
_recordError(...) {
...
final String result = await channel
.invokeMethod<String>('Crashlytics#onError', <String, dynamic>{
'exception': "${exception.toString()}",
'context': '$context',
'information': _information,
'stackTraceElements': stackTraceElements,
'logs': _logs.toList(),
'keys': _prepareKeys(),
});
}
And some reference notes for Crashlytics.logException():
To reduce your users’ network traffic, Crashlytics batches logged
exceptions together and sends them the next time the app launches.
For any individual app session, only the most recent 8 logged
exceptions are stored.
To add to the accepted answer, Crashlytics.instance.recordError() has now been deprecated for the new method FirebaseCrashlytics.instance.recordError(exception, stack).
BONUS TIP:
I had this problem where all the logged exceptions are grouped under the same issue in Crashlytics dashboard. These might be different crashes of the same or different code components. Due to this, I had to manually go through each instance of the crash to verify.
From my own testing, I found out the grouping is based on the top-most line in the stack trace you passed into the method above. Luckily, Dart has an easy way to get the current stack trace using StackTrace.current.
So to properly group the issues: get the current stack trace at the time of the exception and pass it in FirebaseCrashlytics.instance.recordError(exception, stack).
Hope this helps someone out there, I looked everywhere on the internet for a similar issue but can't find any.
Does anybody know what happened with event-listener for location changed for WI-FI provider. I saw a lot of questions about this but no proper answer.
I'm doing everything fine and it is working for older versions of android, but now I updated my SAMSUNG GALAXY TAB 10.1 to ICS and it is not working anymore. Maybe this is a SAMSUNG (or my mobile provider) bug when they implemented their UI into ICS...
I'm registering eventlistener like this (have in mind that it works good in prevous versions of android and I also enabled all location services in settings):
locationManager.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, 0, 0, loclistener);
//refresh time and distance are to 0 so it should trigger location change event
After this request I checked if network provider is enabled and it shows like it is.
Code:
if (locationManager.isProviderEnabled(LocationManager.NETWORK_PROVIDER)) {
Toast.makeText(this, "NETWORK PROVIDER enabled!", Toast.LENGTH_LONG).show();
}
If someone has an idea please help me...
This is known issue:
After device reboot the network location provider works fine but after some time it stops updating.
https://code.google.com/p/android/issues/detail?id=57707
Unfortunately without solution yet.
To track how often the network provider is updating, I modified the onLocationChanged() method to the following:
public void onLocationChanged(Location location) {
dummyText.setText(location.toString() + "\n" + "Elapsed Time (ms): " + (lastTime - location.getTime()));
lastTime = location.getTime();
}
And added:
long lastTime = 0;
...as a global variable.
This will print out the time between updates in milliseconds (after the first fix - first fix will just print the negative time value from the first Location).
I ran the above code on my Samsung Galaxy S3, and the network provider updates around every 20 seconds, so the code seems fine.
I also ran this on a Samsung Dart (from T-mobile, but not activated) on WiFi, and the network provider updates around every 45 seconds.
I also ran this on a Samsung Nexus S 4G (from Sprint, but not activated) on WiFi, and the network provider at first didn't update at all. Restarting the device seemed to fix the problem, and now its updating roughly every 20 seconds.
Based on your comments and my experience, it looks like this issue varies between OEMs and even between device models of the same OEM. It might be another quirk of the lack of the strict enforcement of LocationListener behavior prior to Android Jelly Bean 4.1. Strict enforcement of LocationListener behavior only recently started in Android Jelly Bean 4.1, which is mentioned in the Android developer docs here in under the first requestLocationUpdates method signature:
http://developer.android.com/reference/android/location/LocationManager.html
Prior to Jellybean, the minTime parameter was only a hint, and some location provider implementations ignored it. From Jellybean and onwards it is mandatory for Android compatible devices to observe both the minTime and minDistance parameters.
Also, from my experience, the refresh interval of the NETWORK_PROVIDER location updates on devices that do update is pretty fixed at around 20-30 seconds across many different devices. So, the minTime parameter you pass into the locationManager.requestLocationUpdates() method is likely to be ignored.
Having to reboot the device to get a network provider location is likely due to not getting a response from the Google server that provides this location info. Not sure why rebooting fixes it.
I had the same problem with the NETWORK_PROVIDER. The reason is that when you request for updates, the NETWORK_PROVIDER does not create a callback for the method onLocationChanged(). You also need to call getLastKnownLocation(NETWORK_PROVIDER) in order for it to start updating the location.
The weird thing is that for the GPS_PROVIDER this is not neccessary.
I hope this helps.
Ok. So now I got it working. It is really strange. I restarted all my devices and now it updates. I don't know what happened and I would really like to know what is the reason for this strange behavior. Thank you #barbeau for all your time and help.
I have developed to applications in flex. The one application constantly retrieves data from the internet, while the other can be opened and closed when you want, both apps use the same database. The problem is that at random I get an Error #3119: Database file is currently locked. Is it not possible to have two stable connections in a Adobe AIR environment? Anyone has any solutions?
I think not. Not at once.
I know this is a really old question, but I ran into this issue myself and found a solution for it for those who may come across this. I hope this helps someone, because I know for me, all I could find on this topic was false information, like that given by Konrad. You can, in fact have multiple open database connections. Actually, in my application, I have an asynchronous connection used for writing data to the database (INSERT, UPDATE, DELETE), and a synchronous, read-only connection for reading from the database. On the asynchronous connection, for every execute, I always get an immediate lock by putting all statements in a transaction using
conn.begin(SQLTransactionLockType.IMMEDIATE);
This will allow you to read from the database while writing to it with another connection. Where I ran into a problem is when trying to read from the database from one connection after committing this async statement and before it actually finished writing the data. So, even though the documentation for SQLTransactionLockType.IMMEDIATE states you can still do reads while it is locked, you actually cannot while another statement is actively in the process of writing data.
I got around this by writing my own execute for the synchronous connection. It simply tries to execute, and if it fails due to Error #3119, try again until you succeed. Between each function call, the data will continue to be written to the database and eventually will no longer be busy. Here is the code for that function:
public static function execute(stmt:SQLStatement):void {
try {
stmt.execute();
} catch (e:SQLError) {
if(e.errorID == 3119) {
execute(stmt);
} else {
trace(e.details + "\n" + e.getStackTrace());
if(stmt.sqlConnection != null && stmt.sqlConnection.inTransaction) {
stmt.sqlConnection.rollback();
}
}
}
}
Another gotcha to watch out for with this error (if you're an idiot like me anyway) is to check if you've got the SQLite db file open in a db browser, which can lock the database, and cause this error (and hours of googling and irritation).