I have a problem with WCF. My testing code is pretty simple.
I call a service layer method on my server from my silverlight application and print the result in a textbox.
Everything of this is surrounded by try-catch.
When my service layer method simply returns a constantly defined string there seems to be no problems - however as soon as it calls a more complex method it fails.
While debugging it does not even reach the complex model method; it fails before that inside some auto-generated code from microsoft:
/WuSIQ.jpg
As the error message "NotFound" is not exactly the most helpful or specific you can imagine my trouble googling for hints.
I thought maybe the auto-generated code could only send simple data so I made a temporary string and returned that, but this did not help.
I have already: a client access policy, a service reference added, removed duplicate reference in ServiceReferences.ClientConfig and a ServiceLayer.svc.cs.
I am debugging by running from the main window and my breakpoints are picked up.
Anyone?
I had some errors in the server side method that were quickly found after debugging was fixed.
I fixed this, as I said in comments, setting the project to have "Multiple Startup Projects".
Whenever I had troubles with updating the WCF service methods one of these usually solved it all:
1 Delete all bin and obj folders (specifically selecting re-build might do the same).
2 The servicelayer will not succesfully auto-update (but will work!) unless this:
[ServiceContract(Namespace = "")]
... is set to this:
[ServiceContract(Namespace = "YourServiceLayerName")]
3 Right clicking on the servicereference and selecting "update...".
Sometimes it would stop debugging again, but a forced full re-build would return it to normal.
I hope this helps someone.
Related
My main program is an ASP.Net Core Web API that has a third party library in a hosted service. The third party library is initializing fine but then it throws some errors sometime throughout its lifecycle.
It supplies a way of hooking into the object via an event and will let me know what the error is so that I can handle it but it still throws in the third party library..
Since I am handling the event myself, I want to completely ignore these errors that are occurring in this library. Is there anyway that I can do that?
I have already tried to add a global exception handler and the strange thing is, this exception handler never gets hit. The only way I can get the exception is to set my exception settings to break when CLR exceptions happen like in the picture above
This does not crash my program. For some reason, the program just hangs. When I turn off CLR exceptions in the "Break when thrown" window, then the program runs just fine. It is almost like visual studio is doing something special to handle these types of exceptions that a console version cannot do
The only way that I can seem to get a console version of this running, is attach a visual studio debugger to the process and when the exception is hit, press the green play button "Continue" in visual studio. Otherwise the application just seems to hang on the exception being thrown by the third party library.
The application will run fine as long as visual studio is attached and the CLR break exceptions are not checked
Does anyone know how to make sure that these types of exceptions do not hang the program when released?
Additional Info:
The third party library is a .NET Framework 4 library
The Asp.Net project is targetting "net5.0-windows"
The 3rd party class is probably using multi-threading
if it helps, this is how I am creating the third party class
Handling NullReferenceException in release code（Official advice）
It's usually better to avoid a NullReferenceException than to handle it after it occurs. Handling an exception can make your code harder to maintain and understand, and can sometimes introduce other bugs. A NullReferenceException is often a non-recoverable error. In these cases, letting the exception stop the app might be the best alternative.
However, there are many situations where handling the error can be useful:
1.Your app can ignore objects that are null. For example, if your app retrieves and processes records in a database, you might be able to ignore some number of bad records that result in null objects. Recording the bad data in a log file or in the application UI might be all you have to do.
2.You can recover from the exception. For example, a call to a web service that returns a reference type might return null if the connection is lost or the connection times out. You can attempt to reestablish the connection and try the call again.
3.You can restore the state of your app to a valid state. For example, you might be performing a multi-step task that requires you to save information to a data store before you call a method that throws a NullReferenceException. If the uninitialized object would corrupt the data record, you can remove the previous data before you close the app.
4.You want to report the exception. For example, if the error was caused by a mistake from the user of your app, you can generate a message to help them supply the correct information. You can also log information about the error to help you fix the problem. Some frameworks, like ASP.NET, have a high-level exception handler that captures all errors to that the app never crashes; in that case, logging the exception might be the only way you can know that it occurs.
So after days of research I've finally found an event to hook into to give you error messages from ANY source no matter how many level deep you go in threads.
AppDomain.CurrentDomain.FirstChanceException += CurrentDomain_FirstChanceException;
Hooking into this event it will allow you to see errors from every library and every thread. Simply place the above into you program.cs (or whatever startup file you have) and magically you will be flooded with all of the unknown errors from all of the 3rd party libraries you thought were once flawless.
private static void CurrentDomain_FirstChanceException(object sender, System.Runtime.ExceptionServices.FirstChanceExceptionEventArgs e)
{
Console.WriteLine(e.Exception.Message, e.Exception.StackTrace);
}
I've done so with the following method and low and behold. The third party library was trying to reference another project in an unsafe way and throwing an error. Since I didn't need this other project reference the built exe did not have a reference to this assembly because I had no direct reference to it in the project (darn smarty pants who need to optimize everything). I was able to run correctly because in my visual studio solution, I had a reference to this other project. So the third party library would pick up on it as soon as visual studio connected with the debugger through some sort of dark magic.
Anyways, I made a throw away object that used the project that was required and the issue was solved.
I really hope that this helps someone else and saves them the days it took me to find this.
We are trying to move from server session (IIS) to Redis-backed session. I updated my web.config with the custom sessionState configuration. I'm finding that only SOME of my key/value pairs are being saved. Of the 5 I expect to be in there, there are only 2. I verified all my code is ultimately hitting HttpContext.Current.Session.Add. I verified that my POCOs are marked as serializable. Looking at monitoring, I see that it adds the first two pairs, then everything after that just doesn't make it. No hit, no rejection, no exceptions. Nothing.
Anyone ever see this? Know where I could start to look to resolve?
TIA,
Matt
Update 1: I've switched to using a JSON serializer to store my data. Same thing. Doesn't seem to be a serialization issue.
Update 2: I've now downloaded the source code, compiled and am debugging it. The method SetAndReleaseItemExclusive, which seems to send the session items to Redis, is only hit once, though it should be hit more than once as my web site handle SSO and bounces from page to page to load the user and such. Have to investigate why it's only firing once...
Figured it out. Turns out that my AJAX request to an "API" endpoint without my MVC app did not have the appropriate session state attached. Therefore, the SetAndReleaseItemExclusive was never called. Adding this fixed it:
protected void Application_PostAuthorizeRequest()
{
if (HttpContext.Current.Request.Url.LocalPath == "/api/user/load")
HttpContext.Current.SetSessionStateBehavior(System.Web.SessionState.SessionStateBehavior.Required);
else
HttpContext.Current.SetSessionStateBehavior(System.Web.SessionState.SessionStateBehavior.ReadOnly);
}
I've generated a proxy client for my WCF RIA service class via slsvcutil.exe as described in the Xamarin "Introduction to Web Services" document, however when I try to make a call to one of the async methods, my "completed" event handler never gets called -- after a couple of minutes, the app simply terminates from the Android emulator (it does the same thing in Monotouch as well).
After several days of troubleshooting, I finally found the source of the crash, but have no idea how to fix it. I suspect it's a bug in Mono somewhere, but don't know how to troubleshoot any further.
My generated proxy has a class defined like so:
[System.Diagnostics.DebuggerStepThroughAttribute()]
[System.CodeDom.Compiler.GeneratedCodeAttribute("System.Runtime.Serialization", "4.0.0.0")]
[System.Runtime.Serialization.DataContractAttribute(Name = "ChangeSetEntry", Namespace = "DomainServices")]
[System.Runtime.Serialization.KnownTypeAttribute(typeof(SL5Proxy.ChangeSetEntry[]))]
public partial class ChangeSetEntry : object
{
...
}
(The code above is greatly simplified - there are about a dozen KnownTypeAttribute() lines, but I've determined that the one shown above is the source of the problem. It's important to note that the ChangeSetEntry object does not have any reference to a ChangeSetEntry[] array.)
I found that if I simply comment out the
[System.Runtime.Serialization.KnownTypeAttribute(typeof(SL5Proxy.ChangeSetEntry[]))]
line from the proxy code, everything works 100% correct and my async "completed" handler is called exactly as expected. I don't know why slsvcutil.exe generates the problematic KnownTypeAttribute() line, but it does.
My guess is that there's some kind of infinite recursion that gets created when the ChangeSetEntry class tells the runtime serializer that ChangeSetEntry[] is a known type -- the runtime tries to resolve the known type, comes back to ChangeSetEntry and does it all again.
So I'm curious if anyone else has seen this issue, whether it's a known problem and whether there is a workaround -- perhaps some way to suppress the generation of the KnownTypeAttribute() lines from slsvcutil.exe
I get the following error within Magento CE 1.6.1.0
Warning: session_start() [<a href='function.session-start'>function.session-start</a>]: Cannot send session cookie - headers already sent by (output started at /home/dev/env/var/www/user/dev/wdcastaging/lib/Zend/Controller/Response/Abstract.php:586) in /home/dev/env/var/www/user/dev/wdcastaging/app/code/core/Mage/Core/Model/Session/Abstract/Varien.php on line 119
when accessing /api/soap/?wsdl
Apparently, a session_start() is being attempted after the entire contents of the WSDL file have already been output, resulting in the error.
Why is magento attempting to start a session after outputting all the datums? I'm glad you asked. So it looks like controller_front_send_response_after is being hooked by Mage_Persistent in order to call synchronizePersistentInfo(), which in turn ends up getting that session_start() to fire.
The interesting thing is that this wasn't always happening, initially the WSDL loaded just fine for me, initially I racked my brains to try and see what customization may have been made to our install to cause this, but the tracing I've done seems to indicate that this is all happening entirely inside of core.
We have also experienced a tiny bit of (completely unrelated) strangeness with Mage_Persistent which makes me a little more willing to throw my hands up at this point and SO it.
I've done a bit of searching on SO and have found some questions related to the whole "headers already sent" thing in general, but not this specific case.
Any thoughts?
Oh, and the temporary workaround I have in place is simply disabling Mage_Persistent via the persistent/options/enable config data. I also did a little bit of digging as to whether it might be possible to observe an event in order to disable this module only for the WSDL controller (since that seems to be the only one having problems), but it looks like that module relies exclusively on this config flag to determine it's enabled status.
UPDATE: Bug has been reported: http://www.magentocommerce.com/bug-tracking/issue?issue=13370
I'd report this is a bug to the Magento team. The Magento API controllers all route through standard Magento action controller objects, and all these objects inherit from the Mage_Api_Controller_Action class. This class has a preDispatch method
class Mage_Api_Controller_Action extends Mage_Core_Controller_Front_Action
{
public function preDispatch()
{
$this->getLayout()->setArea('adminhtml');
Mage::app()->setCurrentStore('admin');
$this->setFlag('', self::FLAG_NO_START_SESSION, 1); // Do not start standart session
parent::preDispatch();
return $this;
}
//...
}
which includes setting a flag to ensure normal session handling doesn't start for API methods.
$this->setFlag('', self::FLAG_NO_START_SESSION, 1);
So, it sounds like there's code in synchronizePersistentInf that assumes the existence of a session object, and when it uses it the session is initialized, resulting in the error you've seen. Normally, this isn't a problem as every other controller has initialized a session at this point, but the API controllers explicitly turns it off.
As far as fixes go, your best bet (and probably the quick answer you'll get from Magento support) will be to disable the persistant cart feature for the default configuration setting, but then enable it for specific stores that need it. This will let carts
Coming up with a fix on your own is going to be uncharted territory, and I can't think of a way to do it that isn't terribly hacky/unstable. The most straight forward way would be a class rewrite on the synchronizePersistentInf that calls it's parent method unless you've detected this is an API request.
This answer is not meant to replace the existing answer. But I wanted to drop some code in here in case someone runs into this issue, and comments don't really allow for code formatting.
I went with a simple local code pool override of Mage_Persistent_Model_Observer_Session to exit out of the function for any URL routes that are within /api/*
Not expecting this fix to need to be very long-lived or upgrade-friendly, b/c I'm expecting them to fix this in the next release or so.
public function synchronizePersistentInfo(Varien_Event_Observer $observer)
{
...
if ($request->getRouteName() == 'api') {
return;
}
...
}
I had a connection working but something changed and now the data isn't showing up. It is a simple query that worked before that just returns all entities. I put in break points on the LoadOperation call and it fires and gets 0 entities. I also put a break point on the service itself, and it does not break before the LoadOperation evaluates. After the LoadOperation completes, then the service query is called... well after we needed the data. The only thing that I can think of that could be a problem is that I added 2 WCF services to the solution. Would WCF services stop the RIA from working? Any ideas on what else could cause the problem?
Client:
LoadOperation<Project> loadOp =
this._projectContext.Load(this._projectContext.GetProjectsQuery());
Service:
public IQueryable<Project> GetProjects()
{
return this.Context.Projects;
}
See, real basic, but not working.
You need to put a callback method on your Load operation and then check the results of the LoadOperation.Error when it comes back. In that error you will find the exception which will let you know what the problem is (you will probably have to check the inner exception to get the full details).