We're working on a client-server application, where the client is Angular + AngularJS hybrid, running on Chrome. The server is a spring MVC running on Tomcat.
The communication between the client and server is HTTPS.
Our client sends different REST requests to the server using the AngularJS $http service. Some of them repeat on predefined intervals.
Over the past week we started noticing that every now and then some of the repeating requests fail with ERR_EMPTY_RESPONSE (status is "failed"). For the same request it can fail and 20 seconds later (when the interval is reached) succeed.
It seems like this could potentially happen with every REST request but we mainly notice it on the repeating ones.
The failing requests seem to not reach the server at all as they don't appear in the localhost_access_log.txt file and there is a gap between the repeating requests that did reach the server that indicate the failing requests never reached the server.
The application has been working for quite some time now and without any issues regarding $http requests until last week (around March 25th 2019).
The code that sends these REST requests is not new and has not been changed in years.
It also doesn't look related to the latest Chrome update, as the issue reproduces with Chrome 63, and with the newest Chrome version (73).
We would appreciate your help with this issue.
Thanks.
Related
basically I am facing a problem regarding my Django and selenium website.
My Django function contains selenium code to go and scrape details sent by my front end.
It works perfectly fine on my PC. The scrapper must run until the end of the page and it usually takes hours before reaching the end.
It is basically calling my API endpoint which starts scraping and then returns "done" as a response.
Now I want to host it on ubuntu server on AWS EC2 instance. Which I did and works perfectly fine.
But as I said the scrape works for hours, and till the end of the page it doesn't return anything in response and the request stays alive for hours, which as you know is against the security feature of Nginx and the request dies with a 503 error. The default time for Nginx request is I think 30 seconds or something but I tried changing it but no luck.
Is there a different way of hosting scrappers?
This scrapper will be used by one person but I am thinking of making it public so more people will use it in the future. That's why I would like to know how to make it work with not only 1 user but also multiple. Although first I would like to know how can I make it work with 1 user.
The tech stack:
Python Django(Selenium, BeautifulSoup4, Requests), Reactjs(Axios), Nginx, Gunicorn
I really appreciate you for reading till the end and I would appreciate your feedback and help even more. Thank you for any help!
Am researching activity audits for the last couple days using an asp.net MVC project. I was using contentType=Audit.Exchange and contentType=Azure.ActiveDirectory successfully since the last half of yesterday and this morning up until about two hours ago.
I made no changes to my authorization/authentication code and the tokens look good. Also no changes to the calls themselves. I added some json handling for the response to list subscriptions and when I ran the app to test that code, suddenly I am getting an InternalServerError response to start subscription, list subscriptions and stop subscription. The error is returned after a long timeout (in fact I had to increase the default timeout value).
So as of about two hours ago all the APIs are returning InternalServerError after a long timeout. This is happening on the following APIs:
/activity/feed/subscriptions/start
/activity/feed/subscriptions/list
/activity/feed/subscriptions/stop
The body of the response message is empty. So does not include any error info as described in https://msdn.microsoft.com/office-365/office-365-management-activity-api-reference.
Seems crazy this could be a service outage, so I must be missing something really elemental?
Hmmm. With no further changes to the code, now am getting HTTP 200 responses. If that was a service outage, that was a heck of a long outage for 99.9% uptime.
I have been recently stuck into a strange issue, thrown by a Multi platform Hybrid App in Visual Studio App.. My Development Environment details are as follows :
Visual Studio 2013 Release 3
Cordova 4.0
Angularjs 1.4
Ionic 1.4
Nokia Lumia 1320 [Windows 8.1 OS]
I have a web app that will be interacting with the mobile app, deployed on a server machine that can be accessed both by an internal enterprise network, as well as from internet.
Now the problem is, when i am [the mobile device is] connected to the internal network, the $http call fails with a status code of 0. Internal dig down reveals that the actual returned status code is -1.
However, when i switch over to mobile data in the phone, the ajax call goes smooth and finishes successfully. Now, if i switch back to internal network, it again starts working perfectly. !!!!
The http call is quite simple and uses promise API... I also have some request interceptors.
Any explanations for this strange behavior, or more appropriately a solution for the same ??
After Scratching my head for over 2 days, i was finally able to conclude that it was my browser that was the culprit.
As i said, i was using Windows Phone 8.1, which uses Internet Explorer 11 as the default rendered. Also, My Web server was actually behind a Proxy Server [Apache HTTP].
Now, the Real problem was that the ajax call was returning response status code as 0. And the reason for that was that The Ajax Call was being suspended by The Apache HTTP Proxy Server, because of some tunneling issue. Please note that this was specifically happening with IE11 and Apache HTTP Server.
This was happening since I was using POST request on a HTTPS Based Proxy Server.
Now the solution is too non-technical, but that's what saved my life. In order to save your life from this issue, You must
1. Either convert your POST Request to GET Request
2. Or Before making a POST Request to the Server, make a GET Request to the same server.
In my case, i went with the second approach and it saved my life. Posting this as answer so that it saves someone else too.
You can refer to the following links for more details.
IE10/IE11 Abort Post Ajax Request After Clearing Cache with error “Network Error 0x2ef3”
Making XHR Request to HTTPS domains with WinJS
Configuration:
We have iPlanet web server which sits before WebSphere portal 6.1 cluster (2) deployed in Linux machines.
When user tries to copy a 10 GB file across file systems (NFS mounted), we are using java run time to copy the file across to a different NFS mount, hoping that it would be faster than using any other java libraries.
proc = rt.exec("cp " + fileName + " " + outFileName);
Application deployed is a JSF portlet application.
a) session timeout is 60 mins on the app server and the application
b) we have an Ajax call from the client page to keep the session alive
User receives HTTP 500 within 3 minutes, while our logs show that file is still copying. Not sure why WebSphere is sending HTTP 500?
After 10 minutes are so file is copied, and when he clicks on refresh he can proceed.
Not sure what is causing this HTTP 500.
WebContainer threads are not supposed to be used for long tasks.
He's getting 500 after 3 minutes because that is the time WebSphere decides the thread is hung.
What you should be doing is using a WorkManager to perform that long task and the client can poll to check the status of the task.
If you consider upgrading to WAS v8/v8.5 in the near future a good idea will be to use Asynchronous Servlets for that
The reason that your client receives an HTTP 500 error after a few minutes can happen for a few reasons. Without a stack trace and some relevant logging, it is impossible to know which component within WebSphere "woke up" after 3 minutes and stopped everything. It might be WebSphere's timeout setting for the Web Container thread pool, or it can be some other timeout - should be easily concluded from the logs.
To fix this, you can do one of the following:
Adjust the relevant timeout value (depending, again, on which timeout it is exactly).
Change your design so long-running tasks are executed in the background. You can use WebSphere's Work Manager API for that, or asynchronous beans / servlets.
I am connecting to a 3rd party server on the following wsdl
http://webservices.ticketvala.com/axis2/services/WSTicketvala?wsdl
I am using JAX-WS to generate client code and call relevent method on 3rd party server. 3rd party server may take time between 15-25 seconds to send response.
It works fine on tomcat.
Now when i deploy this to GAE 1.5.3, often i get ScocketTimeoutException in less than 10 seconds. Sometimes it is succesfull taking even 20 seconds. I want to know why it fails many times. And any workaround to increase this response deadline time / to avoid this ScoketTimeOutException forever.
Similarly,
I have another RESTfull service at http://ticketgoose.com/bookbustickets/TGWSStationNameResponseAction.do?" +
"event=getStationDetails&password=123456&userId=ctshubws
I am connecting it through java.net.URL and many times i get TimeoutException. How can i raise this timeout limit to more than 30 seconds?
Thanks
Deepak
No user-initiated request can take more than 30 seconds to complete in Google App Engine:
http://code.google.com/intl/en/appengine/docs/java/runtime.html#The_Request_Timer
And a HTTP request to a external URL in a user-initiated request can't take more than 10 seconds to complete:
http://code.google.com/intl/en/appengine/docs/java/urlfetch/overview.html#Requests
If you need to do the overall work in more than 30 seconds and can do it in background (not needing to return the response directly via HTTP), use Task Queues. Note that the simplest way to do background work with tasks is to use the DeferredTask. And the best part: HTTP requests to external URLs on tasks can take up to 10 minutes to complete.