What's causing this error when running a web worker? - javascript

First time using web workers and I get this error when I try to run it.
First I get a very generic error event sent to my worker.onerror handler. It does not have the message property, the only information is the property type which says error.
Looking at the network tab in dev tools, the request for the worker script looks like it succeeds but it only has provisional response headers and no content to preview.
Preview has:
failed to load response data: connection is closed, can't dispatch pending call to Network.getResponseBody

This caused me to waste about an hour searching for web worker errors. Anyway it turns out that you can get this error if you have a syntax error in your Javascript. At least that is what got me.

Related

Javascript request error, status code 503

I've an issue requesting some data in JS and i get status code 503 and also a message that i don't know what it means,it seems like the memory located to the request is not enought and i would like to know why and how to solve, here the screenshot:
You can manually see it on chrome's dev tools (network section) on this page: PAGE
You can also notice that if you refresh the page more times the requests that fails are everytime different.
I won't write all the code here because is too long, but i leave the link, i'm sorry but this is not my own script and it is compressed.
this is the file that triggers the error.
CODE
THIS IS THE ERROR FROM CPANEL:
couldn't create child process: /usr/sbin/suphp for /home/smmmainp/public_html/index.php, referer: https://smm-mainpanel.com/services
I looked up your site and your server is returning an Exceeded Resource Limit Error Show Image.
"The server is temporarily unable to service your request due to maintenance downtime or capacity problems. Please try again later".
It is not a JavaScript problem, it is an HTTP Request problem, server-side. The "jQuery" that's showing in your Console is probably the Request Initiator, and when some problem happens with your Request, the jQuery needs to Handle it and send an error message. But stills a Server-Side error.
You need to look into your cPanel, go to "Stats" page and look your HTTP Request Limit, in order to know how much requests daily (or per hour) your server handle. Review your Server Provider Plan and contact them.
Best regards!

How to detect if HTTP requests are blocked by a browser extension?

I am trying to detect if a user is using some kind of extension in his browser that could prevent my site from working properly and if so, display a message for the user.
I am testing with an extension called uMatrix, but there are others with a similar approach.
My problem is, that kind of extension will block my HTTP request, but that doesn't return a proper status code (like 403, 404, 500, etc). Instead, when I catch my request, I just get a
Error: Network Error
at [my file name and line number here]
at XMLHttpRequest.handleError (xhr.js:83)
I believe this same error would be thrown in other circumstances, like lack of internet connection, so I can't assume this Network Error means that the user has a "HTTP request blocker".
I was reading a lot about identifying AdsBlocker on this thread and other places, but I don't think it applies to my issue.
Any ideas on how to identify that a user is blocking my HTTP Requests? (Either on purpose or through a browser extension)
I thought I would share here the solution I found, even though I don't think that's the best answer yet.
I am using Axios for my API requests and I found this thread here:
https://github.com/axios/axios/issues/383#issuecomment-234079506
What they suggest it's to check if the response has a status (but in latest Axios, they don't even return a response). If not, it means the server was never reached. That could still mean that there is no internet connection, not necessarily an extension blocked the request. So I adjusted my message to cover both scenarios.
My final code was something like this:
// Note the use of "HEAD", since that will be faster than a "GET"
axios.head(server_url_for_testing).catch(function(error) {
if (!error.response) {
// Display my warning message
}
})

Web worker importScripts DOMException script failed to load

I'm trying to use importScripts
self.addEventListener('fetch', event => {
...
self.importScripts('idb.js');
...
}
to load a library for a service worker for a PWA but keep getting
DOMException: Failed to execute 'importScripts' on 'WorkerGlobalScope':
The script at 'http://localhost:3000/idb.js' failed to load.
The script file is there, content type is correct, application/javascript, and I've tried it with text/javascript too. My developer tools network tab shows the request starting and then failing really quickly, not getting a chance to hit the server. The status code is (failed) net::ERR_CONNECTION_REFUSED when over http and (failed) net::ERR_FAILED over https. Any help appreciated
According to https://developers.google.com/web/updates/2018/10/tweaks-to-addAll-importScripts
Prior to Chrome 71, calling importScripts() asynchronously outside of the install handler would work. Starting with Chrome 71, those calls throw a runtime exception (unless the same URL was previously imported in an install handler), matching the behavior in other browsers.
I have to move importScripts to the top level of my file or my install handler and it works
Based upon the link you provided, you are not running under HTTPS. You need a site under HTTPS to use a service worker.
My original post wrong. #kmanzana pointed out that localhost is considered a "secure origin".
Also, if there is an import statement inside any of the scripts on which you are using importScripts(), you will get this error, and it will not immediately be clear why you are getting it. Caveat emptor.

Ajax chat program errors when retrieving messages [duplicate]

I keep receiving this error when I do some Ajax calls...
It may even be something to do with Geocoding but I really have no idea how to capture the error to display something useful to users... or even how to solve the problem as it seems to just be referencing some kind of pointer or something :S 0x2ef3
SCRIPT7002: XMLHttpRequest: Network Error 0x2ef3, Could not complete the operation due to error 00002ef3.
An image might be more helpful than the error message:
Any ideas at all?
My code fires off 10 ajax calls in 1 second to be processed by geocoding server side.
The error comes up intermittently. Sometimes I get geocoded results and sometimes I get that error. I would say I get it 10% of the time. It completely stops the ajax call from firing my error handler in jQuery.
This is the fix that worked for me. There is invalid mime or bad characterset being sent with your json data causing that errror. Add the charset like this to help it from getting confused:
$.ajax({
url:url,
type:"POST",
data:data,
contentType:"application/json; charset=utf-8",
dataType:"json",
success: function(){
...
}
});
Reference:
Jquery - How to make $.post() use contentType=application/json?
Could not complete the operation due to error c00ce56e
We also encountered similar problems. However, setting the charset as noted in the previous comment did not help. Our application was making an AJAX request every 60 seconds and our webserver, nginx, was sending Keep-Alive timeout at 60 seconds.
We fixed the problem by setting the keep-alive timeout value to 75 seconds.
This is what we believe was happening:
IE makes an AJAX request every 60 seconds, setting Keep-Alive in the request.
At the same time, nginx knows that the Keep-Alive timeout value is ignored by IE, so it starts the TCP connection close process (in the case of FF/Chrome this is started by the client)
IE receives the close connection request for the previously sent request. Since this is not expected by IE, it throws an error and aborts.
nginx still seems to be responding to the request even though the connection is closed.
A Wireshark TCP dump would provide more clarity, our problem is fixed and we do not wish to spend more time on it.
I received the same error (SCRIPT7002: XMLHttpRequest: Network Error 0x80004004, Operation aborted), in our case it was because of JavaScript's same origin policy.
Our web app was making a JQuery AJAX call to our server on Port 8080. The call was getting intercepted and re-routed over SSL (due to server rules mandating that incoming traffic use SSL).
Once we made our web app load through the SSL port the issue was fixed.
I had this problem, a an AJAX Post request that returned some JSON would fail, eventually returning abort, with the:
SCRIPT7002: XMLHttpRequest: Network Error 0x2ef3
error in the console. On other browsers (Chrome, Firefox, Safari) the exact same AJAX request was fine.
Tracked my issue down - investigation revealed that the response was missing the status code. In this case it should have been 500 internal error. This was being generated as part of a C# web application using service stack that requires an error code to be explicitly set.
IE seemed to leave the connection open to the server, eventually it timed out and it 'aborted' the request; despite receiving the content and other headers.
Perhaps there is an issue with how IE is handling the headers in posts.
Updating the web application to correctly return the status code fixed the issue.
Hope this helps someone!
This issue happened in my project because of an ajax GET call with a long xml string as a parameter value. Solved by the following approach:
Making it as ajax post call to Java Spring MVC controller class method like this.
$.ajax({
url: "controller_Method_Name.html?variable_name="+variable_value,
type: "POST",
data:{
"xmlMetaData": xmlMetaData // This variable contains a long xml string
},
success: function(response)
{
console.log(response);
}
});
Inside Spring MVC Controller class method:
#RequestMapping(value="/controller_Method_Name")
public void controller_Method_Name(#RequestParam("xmlMetaData") String metaDataXML, HttpServletRequest request)
{
System.out.println(metaDataXML);
}
I had this error for some time and found a fix. This fix is for Asp.net application, Strange it failed only in IE non compatibility mode, but works in Firefox and Crome. Giving access to the webservice service folder for all/specific users solved the issue.
Add the following code in web.config file:
<location path="YourWebserviceFolder">
<system.web>
<authorization>
<allow users="*"/>
</authorization>
</system.web>
</location>
I have stumbled across this questions and answers after receiving the aforementioned error in IE11 when trying to upload files using XMLHttpRequest:
var reqObj = new XMLHttpRequest();
//event Handler
reqObj.upload.addEventListener("progress", uploadProgress, false);
reqObj.addEventListener("load", uploadComplete, false);
reqObj.addEventListener("error", uploadFailed, false);
reqObj.addEventListener("abort", uploadCanceled, false);
//open the object and set method of call (post), url to call, isAsynchronous(true)
reqObj.open("POST", $rootUrlService.rootUrl + "Controller/UploadFiles", true);
//set Content-Type at request header.for file upload it's value must be multipart/form-data
reqObj.setRequestHeader("Content-Type", "multipart/form-data");
//Set header properties : file name and project milestone id
reqObj.setRequestHeader('X-File-Name', name);
// send the file
// this is the line where the error occurs
reqObj.send(fileToUpload);
Removing the line reqObj.setRequestHeader("Content-Type", "multipart/form-data"); fixed the problem.
Note: this error is shown very differently in other browsers. I.e. Chrome shows something similar to a connection reset which is similar to what Fiddler reports (an empty response due to sudden connection close).
Also, this error appeared only when upload was done from a machine different from WebServer (no problems on localhost).
I just want to add what solved this problem for me, as it is different to all of the above answers.
The ajax calls that were causing the problem were trying to pass an empty data object. It seems IE does not like this, but other browsers don't mind.
To fix it I simply removed data: {}, from the ajax call.
With the Apache 2 change KeepAliveTimeout set it to 60 or above
Upping the directive in the virtualhost for KeepAliveTimeout to 60 solved this for me.
Have encountered the same issue in my asp.net project, in the end i found the issue is with the target function not static, the issue fixed after I put the keyword static.
[WebMethod]
public static List<string> getRawData()
Incase none of these solutions were "clear" enough, essentially IE/Edge is failing to parse your "data" field of your AJAX call properly. More than likely you're sending an "encoded" JSON object.
What Failed:
"data": "{\"Key\":\"Value\"}",
What Works:
"data":'{"Key":"Value"}'
[SOLVED]
I only observed this error today, for me the Error code was different though.
SCRIPT7002: XMLHttpRequest: Network Error 0x2efd, Could not complete
the operation due to error 00002efd.
It was occurring randomly and not all the time. but what it noticed is, if it comes for subsequent ajax calls. so i put some delay of 5 seconds between the ajax calls and it resolved.

PhantomJS Hangs on Page Errors

I am using PhantomJS 2 and the latest CasperJS to test a remote webpage containing some TypeErrors. While logging into the webapp, a popup.created and popup.loaded event are initiated before PhantomJS prints a stacktrace of TypeErrors found when attempting to render the resource. PhantomJS hangs here because PhantomJS does not know how to handle parse errors (Github issue #10687). And my attempts to listen for "error" and "page.error" in both Phantomjs and Casperjs events fail since these TypeError (parse errors) do not throw page.error events (Github issue #10537). I do not own the remote webapp, so I cannot fix these errors. But I need to catch these remote webpage errors and proceed with my testing.
I have unsuccessfully tried to abort loading the resource when the popup.created and popup.loaded events are initiated and I also unsuccessfully attempted to abort the request for the resource when the url of the requested resource matched known url of the .html popup file with TypeErrors. Does anyone know a better way to handle these TypeErrors?

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