I have a partial view which loads a ObjectResult from a SQL procedure. This is using the built in EF method.
public virtual ObjectResult<Something_Result> getSomething()
{
return ((IObjectContextAdapter)this).ObjectContext.ExecuteFunction<Something_Result>("getSomething");
}
So a usual problem is timeouts from the database and I would like to show this. But I cant seem to find this in the exception object from the Ajax.Load() functon .
In the responseText I only get "{"message":"An error occurred while executing the command definition. See the inner exception for details."}" and with status: 500
So is it an easy way to get the inner exception aswell?
Here is the exception thrown by the Ajax.load() function http://i.imgur.com/ZIrTrMU.jpg
And here is the Inner Exception from EF: http://i.imgur.com/LgOhOlB.png
You can put a try catch block in your Data access Layer where you are calling the getSomething method and send appropriate response text up the stack. Depending on where you are putting the catch block, you can check if:
if(ex.Number == -2)
or
if(ex.InnerException != null && ex.InnerException.Number == -2)
return Json(new { successful = false, Message = "Timeout" });
and return appropriate response text as a Json response or if only want to handle TimeOutException you can put in the specific catch block for 'Timeout Exception'
catch(TimeoutException ex)
{ return Json(new { successful = false, Message = "Timeout" }); }
Related
I am implementing payments for my website using the API of an external service (ie. the service of the payment provider).
Let's say the user clicks 'BUY', and then we go to my controller which says something along the lines of:
public function buyFunction() {
$result = $this->ExternalService->pay();
if ($result->success == true) {
return 'We are happy';
}
}
I have also created the aforementioned externalService which has the pay() method:
class ExternalService {
public function pay() {
response = //Do stuff with Guzzle to call the API to make the payment
return response;
}
}
Now, sometimes things go wrong.
Let's say the API returns an error - which means that it throws a GuzzleException - how do I handle that?
Ideally, if there is an error, I would like to log it and redirect the user to a page and tell him that something went wrong.
What I've tried
I have tried using a try/catch statement within the pay() function and using abort(500) but this doesn't allow me to redirect to the page I want to.
I have tried using a try/catch statement within the pay() function and using return redirect('/mypage') but this just returns a Redirect object to the controller, which then fails when it tries to call result->success
I have tried using number 2 but also adding a try/catch block to the controller method, but nothing changed.
In the end, I have found two solutions. In both, I use a try/catch block inside the pay() method. Then I either return 0; and check in the controller if (result == 0) or I use abort( redirect('/mypage') ); inside the try/catch block of the pay() method.
What is the right way to handle this?
How to use the try/catch blocks?
In my experience, avoid handling exceptions let them pass through and handle them accordingly with try catches. This is the most pragmatic approach. Alternatively you will end up checking result is correct in weird places, eg. if ($result) {...}. Just assume it went good, except if the exception is thrown. Bonus: never do Pokemon catches with Exception $e unless you specifically needs it!
class ExternalService {
public function pay() {
try {
response = $client->get(...);
} catch (BadResponseException $exception) {
Log::warning('This should not happen check payment api: ' . $exception->getMessage());
throw new PaymentException('Payment did not go through');
}
return response;
}
}
Assuming you have your own Exception.
class PaymentException extends HttpException
{
public function __construct(?\Exception $previous = null)
{
parent::__construct(Response::HTTP_BAD_REQUEST, 'Unexpected error processing the payment', $previous);
}
}
This enables you to handle the flow in a controller, where it would make sense to handle the redirect. Sometimes if the exception is very integral or common to the web app, it can also be handled by the exception handler instead.
class PaymentController {
public function pay(PaymentService $service) {
try {
$payment = $service->buyFunction();
} catch (PaymentException $exception) {
return redirect()->route('app.payment.error');
}
return view('app.payment.success', compact('payment'));
}
}
I have a Spring boot service with some code like below for parallel async call:
CompletableFuture future1 = accountManager.getResult(url1);
CompletableFuture future2 = accountManager.getResult(url2);
CompletableFuture.allOf(future1, future2).join();
String result1 = future1.get();
String result2 = future2.get();
It works fine when there is no exception. My question is how to handle exception? If getting future1 failed (let say url2 is an invalid url), I still want future2 back as partial result of allOf method. How should I do it?
Thanks!
CompletableFuture comes with a block called exceptionally() which can be used handle the exceptions happen inside the asynchronous code block. Snippet of getResult method for your reference,
public CompletableFuture<String> getGreeting(String url) {
return CompletableFuture.supplyAsync( () -> {
return // Business logic..
}, executor).exceptionally( ex -> {
log.error("Something went wrong : ", ex);
return null;
});
}
In this case the block would return null in case of exception and allOf method would lead to a completion where you can filter the one resulted in the exception when you fetch individual futures.
So basicly im getting this error and its pretty straightforward what it means, my trouble is understanding where it is. The stack trace only points to this method.
async Task GetInfo(string response)
{
var newData= JsonConvert.DeserializeObject<>(response);
this.NewData= newData;
this.MyDataForm.NewData= this.NewData;
if (this.NewData.Age!= this.Age|| this.NewData.Id!= this.Id)
{
await RequestNewData();
}
else
{
//TODO
}
}
This method is inside a try catch within the RequestNewData(); Right now my only guess for what may have been throwing this null exception is that MyDataForm is null at some point.
I need some Elmah logging in a async task executing on my webserver. But when I try to log the error it fails because of the HttpContext.
var httpContext = HttpContext.Current;
Task.Factory.StartNew(() =>
{
HttpContext.Current = httpContext;
try
{
//Execute some code
}
catch (Exception ex)
{
//Generate some error for the user and log the error in Elmah
try
{
ErrorLog.GetDefault(HttpContext.Current).Log(new Error(ex));
}
catch(Exception ex)
{
}
}
});
To get the progress for the task I implemented some polling mechanism. Currently none of the errors are logged to Elmah which make it difficult to solve them.
Also providing the context as parameter doesn't work.
It doesn't work. I get an ArgumentException telling me the expected value doesn't fall within the expected range. With the following stacktrace:
at System.Runtime.InteropServices.Marshal.ThrowExceptionForHRInternal(Int32 errorCode, IntPtr errorInfo)
at System.Web.Hosting.IIS7WorkerRequest.GetServerVariableInternal(String name)
at System.Web.HttpRequest.AddServerVariableToCollection(String name)
at System.Web.HttpRequest.FillInServerVariablesCollection()
at System.Web.HttpServerVarsCollection.Populate()
at System.Web.HttpServerVarsCollection.Get(String name)
at Elmah.ErrorLog.InferApplicationName(HttpContext context)
at Elmah.ErrorLog.GetDefaultImpl(HttpContext context)
at Elmah.ServiceContainer.GetService(Type serviceType)
at Elmah.ServiceCenter.GetService(Object context, Type serviceType)
at Elmah.ErrorLog.GetDefault(HttpContext context)
at Bis.Utilities.Log.ElmahErrorLog.TryLogError(Exception exeption) in D:\Users\A500535\Documents\Projecten\Biobank\Bis\src\Utilities\Log\ElmahErrorLog.cs:line 13
Below is one ugly hack that might get the job done. Essentially, it creates an Error object on a bogus Exception (the prototype) so that the context can be captured while the request is still in flight. Later, when the task started as a result of the request fails, another Error object is created off the actual exception that occurred and then the interesting and contextual bits are selectively copied off the earlier prototype. Unfortunately, the prototype Error has to be created whether or not an exception will occur.
// Create an error that will capture the context
// and serve as a prototype in case a real exception
// needs logging
var prototype = new Error(new Exception(), context);
Task.Factory.StartNew(() =>
{
try
{
// Execute some code
}
catch (Exception ex)
{
// Generate some error for the user and log the error in ELMAH
try
{
// Create a new error without contextual information
// but then copy over the interesting bits from the
// prototype capture at time of request.
var error = new Error(ex)
{
HostName = prototype.HostName,
User = prototype.User,
};
error.ServerVariables.Add(prototype.ServerVariables);
error.QueryString.Add(prototype.QueryString);
error.Cookies.Add(prototype.Cookies);
error.Form.Add(prototype.Form);
ErrorLog.GetDefault(null).Log(error);
}
catch(Exception)
{
}
}
});
When you start a new thread it doesn't get the HttpContext structure. Since Elmah logging requires the HttpContext data, it will fail.
See the following QA:
Elmah Does not email in a fire and forget scenario
for me this worked in a async task called with Task.Run:
Elmah.ErrorLog.GetDefault(null).Log(new Elmah.Error(new NotSupportedException("elmah logging test")));
Currently i am using spring declarative transaction manager in my application. During DB operations if any constraint violated i want to check the error code against the database. i mean i want to run one select query after the exception happened. So i am catching the DataIntegrityViolationException inside my Catch block and then i am trying to execute one more error code query. But that query is not get executed . I am assuming since i am using the transaction manager if any exception happened the next query is not getting executed. Is that right?. i want to execute that error code query before i am returning the results to the client. Any way to do this?
#Override
#Transactional
public LineOfBusinessResponse create(
CreateLineOfBusiness createLineOfBusiness)
throws GenericUpcException {
logger.info("Start of createLineOfBusinessEntity()");
LineOfBusinessEntity lineOfBusinessEntity =
setLineOfBusinessEntityProperties(createLineOfBusiness);
try {
lineOfBusinessDao.create(lineOfBusinessEntity);
return setUpcLineOfBusinessResponseProperties(lineOfBusinessEntity);
}
// Some db constraints is failed
catch (DataIntegrityViolationException dav) {
String errorMessage =
errorCodesBd.findErrorCodeByErrorMessage(dav.getMessage());
throw new GenericUpcException(errorMessage);
}
// General Exceptions handling
catch (Exception exc) {
logger.debug("<<<<Coming inside General >>>>");
System.out.print("<<<<Coming inside General >>>>");
throw new GenericUpcException(exc.getMessage());
}
}
public String findErrorCodeByErrorMessage(String errorMessage)throws GenericUpcException {
try{
int first=errorMessage.indexOf("[",errorMessage.indexOf("constraint"));
int last=errorMessage.indexOf("]",first);
String errorCode=errorMessage.substring(first+1, last);
//return errorCodesDao.find(errorCode);
return errorCode;
}
catch(Exception e)
{
throw new GenericUpcException(e.getMessage());
}
}
Please help me.
I don't think problem you're describing has anything to do with Transaction management. If DataIntegrityViolationException happens within your try() block you code within catch() should execute. Perhaps exception different from DataIntegrityViolationException happens or your findErrorCodeByErrorMessage() throwing another exception. In general, Transaction logic would be applied only once you return from your method call, until then you could do whatever you like using normal Java language constructs. I suggest you put breakpoint in your error error handler or some debug statements to see what's actually happening.