How are exceptions handled by the browser? - html

I decided to figure out how the browser processes the script with only one line in the code, and this line is an exception.
Let's say we have this exception:
throw Error("custom error");
By specification ecma262 ThrowStatement returns a completion record with throw type.
When the script ScriptEvaluation is executed:
If result.[[Type]] is normal, then
Set result to the result of evaluating scriptBody.
Return Completion(result).
this makes it clear to us that a completion record with throw type is returned from ScriptEvaluation
But the ecma262 specification does not say when an error is thrown to the console. I need help to see how whatwg specification intercepts error throw from ecma262.

The behaviour you're seeing is specified in the WHATWG HTML standard (emphasis mine).
https://html.spec.whatwg.org/multipage/webappapis.html#calling-scripts
Otherwise, set evaluationStatus to ScriptEvaluation(script's record).
If ScriptEvaluation does not complete because the user agent has aborted the running script, leave evaluationStatus as null.
If evaluationStatus is an abrupt completion, then:
...
...
Otherwise, rethrow errors is false. Perform the following steps:
Report the exception given by evaluationStatus.[[Value]] for script.
Clean up after running script with settings.
Return evaluationStatus.
https://html.spec.whatwg.org/multipage/webappapis.html#runtime-script-errors-in-documents
When the user agent is to report an exception E, the user agent must report the error for the relevant script, with the problematic position (line number and column number) in the resource containing the script, using the global object specified by the script's settings object as the target. If the error is still not handled after this, then the error may be reported to a developer console.
Also, ECMAScript doesn't actually have a console, that's specified at https://console.spec.whatwg.org

Related

Google Script Exception: Document [spreadsheetID] is missing (perhaps it was deleted, or you don't have read access?)

I occasionally get the Exception message "Google Script Exception: Document [spreadsheetID] is missing (perhaps it was deleted, or you don't have read access?)".
The script is running on a timed trigger every minute so it is obviously finding the document a lot more than it is not, as the Exception only happens maybe once or twice every few days. It happens at different times of the day as well. I also get an error "Exception: Service error: Spreadsheets" with not further info.
You cannot always rely on triggers. Something is happening. Errors too.
If you use such a frequent trigger, you can just wrap it all in error checking and forget about it.
function myTrigger(){
try{
// Trigger's code
} catch(err){
if(/Document ABCD12344 is missing/.test(err.message))
console.warn(err.message, err.stack); // Put it to console. Let it be silent
else throw new Error(err);
}
}

How to handle "Unexpected EOF at target" error from API calls?

I'm creating a Forge application which needs to get version information from a BIM 360 hub. Sometimes it works, but sometimes (usually after the code has already been run once this session) I get the following error:
Exception thrown: 'Autodesk.Forge.Client.ApiException' in mscorlib.dll
Additional information: Error calling GetItem: {
"fault":{
"faultstring":"Unexpected EOF at target",
"detail": {
"errorcode":"messaging.adaptors.http.flow.UnexpectedEOFAtTarget"
}
}
}
The above error will be thrown from a call to an api, such as one of these:
dynamic item = await itemApi.GetItemAsync(projectId, itemId);
dynamic folder = await folderApi.GetFolderAsync(projectId, folderId);
var folders = await projectApi.GetProjectTopFoldersAsync(hubId, projectId);
Where the apis are initialized as follows:
ItemsApi itemApi = new ItemsApi();
itemApi.Configuration.AccessToken = Credentials.TokenInternal;
The Ids (such as 'projectId', 'itemId', etc.) don't seem to be any different when this error is thrown and when it isn't, so I'm not sure what is causing the error.
I based my application on the .Net version of this tutorial: http://learnforge.autodesk.io/#/datamanagement/hubs/net
But I adapted it so I can retrieve multiple nodes asynchronously (for example, all of the nodes a user has access to) without changing the jstree. I did this to allow extracting information in the background without disrupting the user's workflow. The main change I made was to add another Route on the server side that calls "GetTreeNodeAsync" (from the tutorial) asynchronously on the root of the tree and then calls it on each of the returned children, then each of their children, and so on. The function waits until all of the nodes are processed using Task.WhenAll, then returns data from each of the nodes to the client;
This means that there could be many api calls running asynchronously, and there might be duplicate api calls if a node was already opened in the jstree and then it's information is requested for the background extraction, or if the background extraction happens more than once. This seems to be when the error is most likely to happen.
I was wondering if anyone else has encountered this error, and if you know what I can do to avoid it, or how to recover when it is caught. Currently, after this error occurs, it seems that every other api call will throw this error as well, and the only way I've found to fix it is to rerun the code (I use Visual Studio so I just rerun the server and client, and my browser launches automatically)
Those are sporadic errors from our apigee router due to latency issues in the authorization process that we are currently looking into internally.
When they occur please cease all your upcoming requests, wait for a few minutes and retry again. Take a look at stuff like this or this to help you out.
And our existing reports calling out similar errors seem to point to concurrency as one of the factors leading up to the issue so you might also want to limit your concurrent requests and see if that mitigate the issue.

chrome.webstore.install() failure detail string error codes?

I can't seem to find the failure detail string error codes for chrome.webstore.install() 's failure callback... For that matter, I'm not sure if there's documentation for this part of Chrome app development??
From https://developers.google.com/chrome/web-store/docs/inline_installation#triggering
This function [the failure callback] is invoked when inline installation does not successfully complete. Possible reasons for this include the user canceling the dialog, the linked item not being found in the store, or the install being initiated from a non-verified site. The callback is given a failure detail string as a parameter. You may wish to inspect or log that string for debugging purposes, but you should not rely on specific strings being passed back.

How to control triggering of email for the same error in ssis using event handlers?

I am using ssis event handler to trigger an email whenever an error occured in the entire package(PACKAGE+ONEEROR). Here number of emails triggered is equal to number of errors generated.How can I restrict it to one mail eventhough the same error occured 10 times.
Please suggest....
You have a few options. The problem with setting an ONERROR email at the package level is that it will send an email for each error the package encounters. This gets ugly if you have a deep level transform fail, which will error as it fails back up to the package level.
I suggest that you either:
1) Setup ONERROR events at the task level and remove the package level event. Usually this will be good enough. Most tasks will only have one error to report. Be careful with Data Flows, they can act in a similar fashion as the package level events.
2) Setup some sort of advance logging. I’ve seen this done several ways. I’ve seen some people setup Script tasks to log the errors (at the task level) to a variable, and then send a final email containing the variable in the body (at control flow level). I have also seen people call stored procedures (at the task level and package level) for each error that occurs. The sproc would log errors to the DB and allow the package to continue on to the next step/container. The logged errors can then be dumped into a csv and emailed as an attachment.
If you like your current setup, you can try changing the error properties for each container/task. I haven't ever done this, but I do know you can change the way tasks handle errors! I don't like this option because you would possibly be missing errors (maybe? kind of guessing).
update From another solution - If you want to keep your current email ONERROR and simply prevent certain errors from "bubbling" up and sending emails, you can follow this link to learn how to gracefully handle errors. You could prevent certain tasks errors from reaching your ONERROR event at the package level. good luck.

Windows workflow - Cannot handle exception in ReceiveActivity

I have a sequential workflow, which is hosted in IIS as a Workflow Service.
My workflow starts with a ReceiveActivity, and inside the ReceiveActivity a call is made to a WCF service with a SendActivity. If this call receives an exception, there is a FaultHandlerActivity on my ReceiveActivity which is meant to handle the call, and send a default value back to the client.
What is happening in my client is that an exception on the SendActivity is bubbling back to the client as a FaultException, even though my FaultHandlerActivity is running (I verified this by logging the beginning and end of the single CodeActivity in my fault handler)
My question is: How can I swallow exceptions ocurring in the SendActivity, without a FaultException being returned to the client?
OK, I figured it out.
My receiveActivity had a fault handler directly on it. What happens then is that if any child activity raises an exception, the fault handler on the receive activity is invoked, and it is also set to a Faulted state, and the exception received is returned to the client application - whether I wanted that or not.
The solution was to add a sequence activity inside the receiveActivity, do all of the processing inside the sequence activity, and add a faultHandlerActivity to the Sequence, which sets up my default return value.
The receive activity is never faulted, and the exception is not returned to my client, but the default value set up in the Sequence's FaultHandler is returned.
Hopefully this will help someone else with the same issue