MVC response view not displayed by browser - model-view-controller

I have an ASP.NET MVC application that works fine most of the time. Occasionally, users complain that they submit an action request and the application appears to hang (i.e. no response is received by the browser even after several minutes and eventually the browser times out.) I can see from HttpWatch that the request is being submitted, IIS logs show the server receiving the request and the application logs show the request action being invoked and completing normally. HttpWatch gives an error which is usually 'ERROR_INTERNET_CONNECTION_RESET' or 'NS_ERROR_NET_RESET'.
The application also does a number of Ajax requests to the same server which all appear to function normally - the 'hang' situation only occurs on full HTTP page loads (i.e. not Ajax requests.)
At first I thought this was browser related, but it happens both with IE8 and IE9 and with FireFox 17, which may be the reason for the two different error messages posted above.c
Does anyone have any idea what the problem is?

Related

How HTTP redirects(302) works during an ajax call

I was asked to implement a "one session per account" limitation on an old java 7/struts 1 web application.
During development, I'm getting a behavior which I can't really understand.
So if there's an account "Account-A" currently logged in with a session "Session-1234" and then the same account gets logged in but with a different session "Session-4567" then the session "Session-1234" is marked to be invalidated in the next request performed by that session.
During the process of invalidation of the "Session-1234", one of the steps is redirecting(302) the client to the login page.
Now is what I don't understand.
If the request is coming in "synchronous" mode, everything works as expected.
User clicks some link
Server -> invalidates session and redirects(302) login.
Browser -> detects 302 looks for Location header and performs a get.
Server -> serves the resource.
Browser -> show login and update the URL.
If the request is coming in "asynchronous" mode aka AJAX, now I have problems because what happens is that the page never changes and the content of the login is displayed right there.
My question is not how to solve this "problem", but rather have a really good grasp on why it behaves like this.
If you are working with a programmatic client, you have 2 main options:
Don't use cookies, use the Authorization header and let the server emit a 401, telling the client their token is now invalid.
With your javascript client, read if the server returned a 302 response and Location header and respond to that.
#2 is basically a hack that lets you mimic the standard browsers' behavior. #1 is more appropriate for an API.

Scraping a website made with ICEfaces (session expired on consecutive ajax POST requests)

I'm trying to scrape a website created with the ICEfaces web framework via a node.js script. I've managed to handle the login just fine, and then get some data from the main page (namely ice.session and ice.view, along with the JSESSIONID cookie returned by the login response).
The problem I've run into is when I try to do an AJAX POST request to the /block/ URLs. If I do the request by itself, it returns some data (just not the data I need), but if I do it after any other request, I get <session-expired/> as a result. It doesn't even matter which of the ICEfaces /block/ URLs I send the request to (I've tried with /send-receive-updates, /dispose-views, and even /ping). I've even tried the same request twice in a row just for kicks, and I always get a <session-expired/> response in return on the second one. I've monitored the requests when I browse the page with Chrome, and as far as I know I'm sending all the correct form data (as well as the correct headers). The page works just fine when I load it in the browser, so there must be something I'm not doing right.
Apparently, the order in which you do the requests matters in ICEfaces (i.e. it's not stateless, which kind of makes sense I guess). I just moved the requests around and finally got the response I desired.
IceWindow, IceView and ViewState
Need to be passed as a parameter whenever you do an ajax submit.
Managed bean takes the previous instance of the current view view using ViewState value.

firefox repeating text/html GET http requests to the web app

Via Firefox, if I do a GET text/html request to my web app, I get a 200 response back, and then Firefox sends 3 more of the same request right afterward. All return 200s. Does anyone know what would cause this?
*Some other observations about the issue:
In Firebug's network tab, only one request shows up. I can only see the extra requests using Tamper Data or another tool that sees the Http requests sent from my browser.
This issue does not happen in prior versions of my web app. When I compare the responses that get returned by the two different versions of the web app, I can't see anything that would cause this issue (but then, I really don't know what to look for). The responses are identical except for the web app's cookies, which are different.
This issue happens with JavaScript enabled or disabled.
Something similar is happening with Chrome, though it seems to be sending only 2 extra requests.
I don't see any browser redirects in the Html header.
This is only happening with text/html requests, not css requests, for example.
All 4 responses returned seem to have the complete Html page in the body, and they also have the cookie that the web app uses.
In Tamper Data, the 'Load Flags' column (whatever that is) says the following: First request is VALIDATE_ALWAYS_LOAD_DOCUMENT_URI LOAD_INITIAL_DOCUMENT_URI; second and third requests are LOAD_NORMAL; fourth request is LOAD_FROM_CACHE VALIDATE_NEVER
I don't see it happening with POSTs
It does not happen when the response is a 302.
If I go into the firefox config and set network.http.max-connections-per-server to 1, then Firefox only sends one request (the issue does not occur). (I don't think I can ask all our users to do that. :-))
*Why this issue is a problem:
This site has been around a long time and wasn't designed for this behavior. It's probably not going to go well.
(edited to add new findings)

Google chrome requests multiple times for a page asp.net mvc 3

Google chrome is sending multiple requests for a page.
I'm using c# asp.net mvc 3 razer. when i tested with other browsers, it is only executing one time. i checked the requests with fiddler. so i noticed that chrome is sending 2 requests.
Any idea about how to prevent the additional requests?
Thanks.
Do you have a favicon? Chrome will send a request for favicon on every single request until it finds one.
server socket receives 2 http requests when I send from chrome and receives one when I send from firefox
Do you have any JavaScript on this page that make calls to the server?
If so, perhaps the events with the JavaScript are firing differently among the different browser which would explain why you see a double hit in some browsers but not others.
Do you have any chrome extension that might trigger the second request? I know that HTML validator extension for chrome occasionally does this. Try disabling all plugins extensions and see if the issue still occurs

Saving all browser's (any) AJAX activity to disk

I'm developing web application that uses AJAX a lot. It sends several AJAX requests to server per second and update page's content based on the request result.
Is there a way I can save all responses sent from server to browser using AJAX to disc in order to analyze it later?
It is not good to make 'alert' after each request because there are too many requests and I'll not be able to see if the browser works well in this case.
I've tried to use firebug or greasemonkey for Firefox but I failed to save data to disk using them.
Is there any solution for it? Thanks for your help.
Have you tried Fiddler?
It's an application which monitors all http traffic. It's good, and it's free.

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