I've got a SpringMVC application that is randomly not returning a response to AJAX requests. Or rather, it would appear that it is not returning the response.
In my Network graph (Chrome or Firefox), I see a GET request being made, and I see the full stack trace on the server side which is handling/responding to the request. However, the browser never seems to receive a response to the request as the GET method never completes.
I am completely clueless as to how/where to start tracking this down.
I am running on Tomcat 7.0.42 and using AngularJS on the front side. I have my firewall completely stopped, so I do not believe that it is related to blocked ports/communications.
Where/how can I validate that a response is being committed? Furthermore, how can I isolate where this disconnection is occurring and why the browser isn't receiving any response? I cannot seem to replicate this behaviour when I issue manual requests via Postman.
I am doing the dev work on OSX v10.7.5.
Wow. After several hours of trying to dig around and find the solution, I installed Wireshark and decided to look at actual packets. Turns out I was getting double requests for a single get, but to 2 different ports. After further inspection (checking to see what was listening on the port), I noticed that it was the Sophos Anti-Virus that was seemingly intercepting the request and not responding.
I'm still not sure quite how the AV intercepts the requests before passing them along, nor how it decides to abort a response, but turning off has made a world of difference.
Hopefully this learning experience will help someone else if they get stuck with something similar.
SpringMVC is pretty rock solid and the only thing I can imagine is that your handler is not returning a response under certain instances. Look in your code for conditionals or exception handlers that don't return a proper response.
Related
I am implementing single page application(SPA) using of Angular Js, MongoDb. And I am using rest call with promises. Rest call working fine in Chrome, Mozila browser which is using for development. But rest call is not working in IE-11. It is giving me 500 Internal Server Error.
I am not able to find out line of rest call. Because it is not showing line number. But I can share sample code of rest call.
Rh.all('apicall').get('dbname/_aggrs/'+ ar_dep +'?avars=' + query).then(function (d) {
console.log("response data");
});
Above call is not printing console. Because It is breaking in IE-11, But these rest call working fine in other browser.
If I putt direct path not with variable then it is working in IE-11.
Working Rest Call below
Rh.all('apicall').get('dbname').then(function (d) {
console.log("response data");
});
NETWORK in Console(IE-11)
IN CHROME
I am updating my question. Because I found some difference parsing url, Because of restheart.
IN CHROME:
Rh.all('apicall').get('dbname/_aggrs/'+ ar_dep +'?avars=' + query)
After parsing
localhost:8080/apicall/dbname/_aggrs/rout?avars={%22routes%22:%22US%22}
In query object I have routes:us. So in chrome it parsing %22--%22 place of " ".
IN IE-11
Rh.all('apicall').get('dbname/_aggrs/'+ ar_dep +'?avars=' + query)
After parsing
localhost:8080/apicall/dbname/_aggrs/rout?avars={"routes":"US"}
In IE-11, It is not parsing double qoutes to %22 %22. It is parsing same as string.
A 500 error is always related to the server. The symptoms may only occur with a specific browser, but it is the server that is failing; the request that is being sent to the server is causing the server-side code to fail in some way.
Error 500 on its own is too generic; without knowing more details about the error, it is always very hard to diagnose, and frankly I won't be able to give you a definitive answer here.
At your end, you should rule out the obvious, and check your browser settings in IE. Specifically, any settings that might cause it to fail to communicate properly with the server. For example, make sure that cookies are enabled and are working properly.
But the first thing you should do is discuss with the vendor or developers of the API because they will have access to the server error logs, and they will want to know about it if their code is throwing a 500 error.
However, if you do want to investigate at your end, the fact that it is specific to one browser is a clue. If the other browsers are working, then what this tells us is that this one browser (IE11) is sending the request with something about it that is different to the other browsers, and it is that something that is triggering the server-side code to fail. This gives us something to work with in the investigation.
So the first thing to do is to examine the request in all browsers. Use the F12 dev tools in Chrome, Firefox and IE, and get to the point where you've made the same call in all three of them, and it works in FF and Chrome but not in IE11.
In the dev tools, you should now be able to examine the request details for all three. Compare them.
Start by looking at the request data -- ie the actual query string that was sent. If there are differences, consider whether any of these differences may be responsible for the error. Something may stand out obviously; eg if IE has truncated a variable or something like that. If this solves the problem, then great.
If it doesn't help, then you need to look in more detail. Maybe there are some differences but they don't look like they should break anything? Modern browser dev tools allow you to edit and re-send a request, so try editing the request in Chrome or Firefox's dev tools, and make the parameters the same as the ones from IE that failed. Now try re-sending that request. If you're lucky, this will cause the request to fail in the other browser, which will allow you to show that a specific set of data is the problem (rather than a specific browser). You mentioned that it's a third party API, so you'll then need to discuss with the API vendor to find out why that query breaks their API.
If you still haven't found the problem at this point, and you're sending identical queries in both browsers, and you're logged in as the same user, then the next step is to look at the request headers.
There is one request header that will definitely be different: the User Agent string. But there may be others too. Again, try re-sending request that works in Chrome, but with headers from the failing request in IE (including the UA string). Does the request now fail in Chrome? If so, narrow down which headers are different that make it fail.
Again, if this allows you to find a specific set of request data and headers that causes the problem, then you will need to discuss with the API vendor.
If all of this doesn't help, then try looking at the cookies. You already checked that cookies are working, so this seems like a long shot now, but again compare the cookies between browsers, and see if there's anything obviously different about them.
I hope the above is enough to help you diagnose the issue.
The OPTION/POST Request is failing inconsistently with a console Error as err_timed_out. We get the issue inconsistently, it's only observed sometimes. Otherwise the request gets proper response from the back end. When it's timing out, the request doesn't even reach the server.
I have done some research on the stuff and found that due to maximum 6 connections to a resource restrictions it may wait for getting a connection released. But, I don't see any other requests pending ,all the other requests were completed.
In the timeline I can always see that it stalled for 20.00 seconds. Most of the time the time is same. But, it only shows that its been stalled for some time nothing else in the timeline.
The status of the request shows failed ERR_Connection_Timed_Out. Please help.
The Network Timing
Console Error
I've seen this issue when I use an authenticated proxy server and usually a refresh of the page fixes it.
Are you using an authenticated proxy server where you are seeing this behavior? Have you tried on a pc with direct access (i.e. without proxy) to the Internet?
I've got the same problem when I choose another ISP. I thought I would have only to put my new ID and password, but it wasn't the case.
I have an ADSL modem with a dry loop.
All others services were fine (DNS resolution, IP telephony, FTP, etc).
I did a lot of tests (disable firewall, try some others navigator, try under Linux, modem default factory, etc) none of those tests were successful.
To resolve the problem ERR_TIMED_OUT, I had to adjust the MTU and MRU values. I put 1458 rather than 1492, which is the default value.
It works for me. Maybe some ISPs use different values. Good luck.
My Google App Engine app, which uses the Channel API works well some of the time. Intermittently, though, the js code connecting to the channel generates an error. In socket.onError, the error code is set to 400 and the description is set to an empty string. I have checked that the token being used to connect is valid. I also tried recreating the channel in socket.onError, by first calling socket.close() but that does not seem to work. Often there is a series of failures before a success. The client js is running on Safari on iOS. Any ideas on how to fix or work around the problem will be welcome. Right now, my best workaround is to keep trying till I succeed, increasing the interval between attempts on each failure. The server side presence API does not help, since the 'connected' hook is not called reliably.
It is known issue http://code.google.com/p/googleappengine/issues/detail?id=4940 and it was accepted. As you see the status of issue is not fixed. Feel free to star it.
I know double posting is bad (issue starred & comment posted)... but I suspect this thread might get more attention than the issue comments ^^
As far as we are concerned, it's at the very least a documentation issue:
https://developers.google.com/appengine/docs/java/channel/javascript still
states " An onerror call is always followed by an onclose call and the channel object will have to be recreated after this event"
It is only true for, as far as we have guessed, error codes 400 and 401 (which are strings, not numbers, btw, so beware of === in the js code).
It is untrue for other error codes (we have logged at least the -1 code).
There should be a documentation covering all error codes and their (expected) management.
Atm, we have a "channel manager" that reuses the same channel token when code is not 400 or 401, and that makes sure onclose is called once and once only per Socket.
Before that, we were trying to close properly, and reopen (new underlying Socket) with a shiny brand new token: usually we got an error 400 followed by an error -1.
FUI we first detected this behavior on iOS, quite recently (regression ftw? Before that iOS was dandy). Reopening the socket after a code -1 is not a panacea: sometimes it will succeed (onopen properly called), and then fail silently (no message received, no onerror called).
Generally, we also noticed more consistent behavior on desktop browsers than mobile ones, across all user agents and platforms (more on that: yay! Other issues incoming! Especially android...)
OK, this post might have been useful after all. Thx!
[EDIT: corrected a mistake... we don't reuse the channel object nor the socket object, only the token]
I contacted Google support about this issue.
When a error 400 happens it's because a timeout (one minute it seems) happened. This timeout generates a disconnection (url disconnected is called and you should remove the client id of the database).
Then, a new channel must be created with a new client id.
But it is not enough. We have to use this jquery command line : $('#wcs-iframe').remove();
Just inside the js onerror function and before to try to recreate the channel.
I was modifying a WCF service to increase the timeout for a Silverlight client. Before modifying the timeouts I'm seeing CommunicationObjectAborted exception (The HTTP request to [URL] was aborted). At first I only modified the web.coffig of the WCF and it had no effect. I then followed this post (http://blog.ecofic.com/?p=379) and edited ServiceReferences.ClientConfig as well. Now I'm seeing a No endpoint exception. The exception was not thrown immediately after the client connects to WCF, but after about 1 minute after it connected to WCF. I suspect it has something to do with the timeouts?
I set open, close, send and receive timeouts to 5 minutes in both config files.
Any idea? Thanks!
As Richard pointed out, sendTimeout only be needed to set on the client (your Windows Phone app in this case). Double check the ServiceReferences.clientConfig as manually added value might get overwritten by Visual Studio.
Also you can check this post for using Fiddler on Windows Phone (emulator).
You should use Fiddler to analyse the requests performed by your application. This way, you will be able to know what happen when the request is sent, where exactly it is sent (if it is sent), and the response code from the server.
Obtaining these informations is the first step on the way to troubleshoot your issue.
I've got a Silverlight application that makes a cross-domain request. The clientaccesspolicy.xml file exists on the server I am making a request to and is correctly configured.
I know that it is correctly configured because when I use the application to make a request from my machine I receive a response with no problem.
When a second individual on a corporate network about 300 miles away tries to use the same application, launched from the same URL, to make the same request, he instead gets a security exception.
Here's the odd part. I requested that he download Fiddler so that I could see the request and it's response, and thereby gain some insight into the problem, but when he runs the app with Fiddler open, the request succeeds.
This happens in both Chrome and IE. With Fiddler everything is fine. Without it, it doesn't work.
We've tried clearing his history, deleting the Silverlight app from the cache, everything I can think of.
The request is being made to a private network (which he is on), I make the request through a VPN connection to that network (in case for some reason that matters).
Any thoughts as to what's causing this bizarre problem?
Despite the fact the Fiddler "fixes" the issue it would still be worth while getting this second individual to save a .saz file from fiddler for the successfull set of sessions and then for you to compare them with a successfull set you have from your own machine.
An analysis of the differences may reveal a potential cause when fiddler is not in place.
Another approach would be to use a network protocol anaylser such as Wireshark. The elimination of the proxy that Fiddler represents may be enough to expose the problem, of course such tool is much more technical.
This post is simply to catalog the solution for future users. Thanks to everyone who helped.
The actual problem turned out to be (just as EricLaw -MSFT- suggested) that the client's machine was zoning the request URL as Intranet and the Silverlight application as Internet, and I am not permitted to make requests across zones.
EricLaw's direct responses may be viewed in the comments under the original question.
The URL below (provided by Eric) contains information regarding the denial of cross-zone request, as well as solutions.
msdn.microsoft.com/en-us/library/bb250483(VS.85).aspx