Multiple ajax get requests of same route but different query string - asp.net-mvc-3

I have had this for a couple of days now.
I have a simple search form. When form is submitted the server searches for some data from another server and return data to the screen. When the submit completes it gets some javascript from the server based on the results returned from the search. the javascript then makes multiple concurrent jquery get requests, lets say 4, to the asp.net mvc3 webapp.
I have demonstrated that all the get requests fire at the same time in Firebug but when debugging my app with VS the breakpoints only get hit once the previous request completes.
The actions are the same but the querys are different; ie
/Home/Details/040801
/Home/Details/040802
/Home/Details/040803
So these are different URLs and, from what i found out, FF should treat them differently.
So my questions are:
Am I missing something obvious?
Does IIS have some funny blocking on the same route?
Is it a session cache issue? I am locking lock (lockobject){} on writes to the common session variables.
Im not using ViewBag or TempData.
The page load times, even when everything is cached in the Session, are still noticeably synchronous.
Windows Server 2008 R2
Using IIS 7.5
ASP.NET MVC 3
VS2010 Chrome or FF browser
I have my routes set up as follows:
routes.MapRoute(
"Default", // Route name
"{controller}/{action}", // URL with parameters
new { controller = "Home", action = "Index" } // Parameter defaults
);
routes.MapRoute("Details", "{controller}/{action}/{id}/{booking}", new { id = UrlParameter.Optional, booking = UrlParameter.Optional});
Nothing special there as you can see.
Sample code from one of the blocked routes:
public ActionResult Details(string id, bool booking = false)
{
if (booking)
{
return BookingDetails(id, true);
}
Dictionary<string, FlightDetails> detailDic;
string scenarioInput;
lock (DetailsLock)
{
if (Session["DetailDic"] == null)
{
Session["DetailDic"] = new Dictionary<string, FlightDetails>();
}
detailDic = (Dictionary<string, FlightDetails>)Session["DetailDic"];
}
if (detailDic.ContainsKey(id))
{
return PartialView("Details", detailDic[id]);
}
lock (GuidLock)
{
if (Session["DetailGuids"] == null)
{
Session["DetailGuids"] = new Dictionary<string, string>();
}
scenarioInput = ((Dictionary<string, string>)Session["DetailGuids"])[id];
}
// query results list
string queryText = string.Format("<View><Query><Where><Eq><FieldRef Name=\"Title\" /><Value Type=\"Text\">OUT {0}</Value></Eq></Where></Query></View>", scenarioInput);
ListItemCollection oList;
int counter = 0;
do
{
oList = SharepointHelper.GetListFromSharepoint("ListName", queryText, ClientContext);
counter++;
Thread.Sleep(1000);
} while (oList.Count == 0 && counter <= Timeout);
if (oList.Count == 0)
{
return PartialView("Details", (object)null);
}
var item = oList[0];
FlightDetails flightDetails = CreateFlightDetails(id, scenarioInput, item);
lock (DetailsLock)
{
detailDic.Add(id, flightDetails);
}
return PartialView("Details", flightDetails);
}

when using session object in server-side your async calls wait for session object released by other request. Becuase of this async ajax calls act like sync. You have to use session as readonly in that action.
Add this attribute to action you call if you dont write anything to session.
[SessionState(SessionStateBehavior.ReadOnly)]

Related

How to prevent additional page requests after response sent

I have configured a listener on kernel.request which sets a new response with redirect when the session time has reached a certain value. The listener works fine and redirects to a certain page, on the next request, after the session has ended. But my problem is on the page I have many links and if I press multiple times the same link, the initial request with the redirect is cancelled/stopped and a new request is made with the last link pressed and so it passes my redirect even though the session has ended and is destroyed. So, my question is how to prevent additional requests/link presses after the firs request is made?
Here is my code:
public function onKernelRequestSession(GetResponseEvent $event)
{
$request = $event->getRequest();
$route = $request->get('_route');
$session = $request->getSession();
if ((false === strpos($route, '_wdt')) && ($route != null)) {
$session->start();
$time = time() - $session->getMetadataBag()->getCreated();
if ($route != 'main_route_for_idle_page') {
if (!$session->get("active") && $route == 'main_route_for_site_pages') {
$session->invalidate();
$session->set("active", "1");
} else {
if ($time >= $this->sessionTime) {
$session->clear();
$session->invalidate();
$event->setResponse(new RedirectResponse($this->router->generate('main_route_for_idle_page')));
}
}
} else {
if ($session->get("activ")) {
$session->clear();
$session->invalidate();
}
}
}
}
Thak you.
Idea #1: Simple incremental counter
Each request sends sequence number as param which is being verified as expected at the server.
Server increments the number and sends it back via response
the new number is used in future requests
Basically, if server expects the SEQUENCE number to be 2 and client sends 1 the request is to be rejected.
Idea #2: Unique hash each time
Similar to the idea above, but uses unique hashes to eliminate predictive nature of incremental sequence.
I resolved the issue using JQuery: when a link was pressed I disabled the other ones and so only one request is made from the page:
var isClicked = false;
$(".menu-link").click(function(e) {
if(!isClicked) {
isClicked = true;
} else {
e.preventDefault();
}
});
Thanks.

ASync Recaptcha in MVC3

I've implemented ReCaptcha in MVC3 using ReCaptcha.net NuGet package http://recaptchanet.codeplex.com/wikipage?title=How%20to%20Use%20Recaptcha%20in%20an%20ASP.NET%20MVC%20Web%20Application. All working well, except I'd like to see if I can implement this as Async as it is sometimes quite slow, and we may have some volume on these pages.
The instructions say
RecaptchaVerificationResult recaptchaResult = await recaptchaHelper.VerifyRecaptchaResponse();
if (recaptchaResult != RecaptchaVerificationResult.Success)
{
ModelState.AddModelError("", "Incorrect captcha answer.");
}
however, this is using the MVC4 await syntax. Is there a way I can use this method within the MVC3 async framework?
I did try a quick hack, converting the controller to AsyncController naming the method with an Async suffix and wrapping the entire action in a Task.Factory.StartNew(() => { ... }); while using the non-async syntax, but RecaptchaVerificationHelper recaptchaHelper = this.GetRecaptchaVerificationHelper(); complains about a lack of HTTPContext.
So, can anyone help me with doing ReCaptcha asynchronously in MVC3
In the end, I've dropped using the NuGet package, and simply process the captcha's using the code below, binding the recaptcha fields in the controller method.
public bool ProcessCaptcha(string recaptcha_challenge_field, string recaptcha_response_field)
{
const string verifyUrl = "http://www.google.com/recaptcha/api/verify";
var res = true;
var ip = Request.UserHostAddress;
if (ip == "::1") ip = "127.0.0.1";
var myParameters = string.Format("privatekey={0}&remoteip={1}&challenge={2}&response={3}", Config.CaptchPriv, ip, recaptcha_challenge_field, recaptcha_response_field);
using (WebClient wc = new WebClient())
{
wc.Headers[HttpRequestHeader.ContentType] = "application/x-www-form-urlencoded";
string HtmlResult = wc.UploadString(verifyUrl, myParameters);
var split = HtmlResult.Split('\n');
if (split[0] == "false") res = false;
}
return res;
}
With this in place, I split my original controller method into a Async/Completed pair, and wrapped the work it does in Task.Factory.StartNew(() => { ... }), following the pattern outlined here http://www.deanhume.com/Home/BlogPost/mvc-asynchronous-controller---the-basics/67 which seems to work perfectly.

WebService ASP.NET MVC 3 Send and Receive

I've been racking my brain for a couple of days now on how to approach a new requirement.
I have two websites. The first one lets the user fill out an application. The second website is an internal website use to manage the users applications. I need to develop a "web service" that sends the application data from website 1 to website 2 and return a response to website 2 of success or failure. I have never done a web service before and I'm a bit confused on where to start. I've been reading various examples online but they all seem to be just a starting point for building a webservice... no specific examples.
So for posting the data website 1, what would my controller method look like? Do I use Json to post the data to website 2? What would and example of that look like? Is there some form of redirect in the method that points to website 2?
So for posting the response back to website 2 what would that controller method look like? I assume I would use Json again to send the response back to website 1? Is there some form of redirect in the method that points back to website 1?
I would use JSON and POST the application to the web service.
First I am assuming the application data is contained in some type of object. Use JSON.Net to serialize the object into JSON. It will look something like the following code.
var application = new Application();
string serializedApplication = JsonConvert.Serialize(application);
Second is to POST the code your endpoint(webservice, mvc action). To this you'll need to make a HTTPRequest to the endpoint. The following code is what I use to make to POST the code.
public bool Post(string url, string body)
{
//Make the post
ServicePointManager.ServerCertificateValidationCallback = (sender, certificate, chain, errors) => true;
var bytes = Encoding.Default.GetBytes(body);
HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);
Stream stream = null;
try
{
request.KeepAlive = false;
request.ContentLength = bytes.Length;
request.ContentType = "application/x-www-form-urlencoded";
request.Timeout = -1;
request.Method = "POST";
stream = request.GetRequestStream();
stream.Write(bytes, 0, bytes.Length);
}
finally
{
if (stream != null)
{
stream.Flush();
stream.Close();
}
}
bool success = GetResponse(request);
return success;
}
public bool GetResponse(HttpWebRequest request)
{
bool success;
using (HttpWebResponse response = (HttpWebResponse)request.GetResponse())
{
using (Stream responseStream = response.GetResponseStream())
{
if (response.StatusCode != HttpStatusCode.OK && response.StatusCode != HttpStatusCode.Created)
{
throw new HttpException((int)response.StatusCode, response.StatusDescription);
}
var end = string.Empty;
using (StreamReader reader = new StreamReader(responseStream))
{
end = reader.ReadToEnd();
reader.Close();
success = JsonConvert.DeserializeObject<bool>(end);
}
response.Close();
}
}
return success;
}
So now you have can POST JSON to an endpoint and receive a response the next step is to create the endpoint. The following code will get you started on an endpoint in mvc that will receive an application and process it.
[HttpPost]
public ActionResult SubmitApplication()
{
//Retrieve the POSTed payload
string body;
using (StreamReader reader = new StreamReader(Request.InputStream))
{
body = reader.ReadToEnd();
reader.Close();
}
var application = JsonConvert.Deserialize<Application>(body);
//Save the application
bool success = SaveApplication(application);
//Send the server a response of success or failure.
return Json(success);
}
The above code is a good start. Please note, I have not tested this code.
You have obviously more than one client for the data & operations. so a service is what you are looking for.
ASP.NET MVC is a good candidate for developing RESTful services. If you (and your Manager) are ready to use beta version, Then Checkout ASP.NET-Web API.
If you want to stay with a stable product, Go for MVC3. you may need to write some custom code to return the data in XML as well as JSON to server different kind of clients. There are some tutorials out there.
So create a Service (ASP.NET MVC / WCF Service) .You may then create 2 client apps, one for the external clients and another for the Internal users. Both of this apps can call methods in the Service to Create/ Read the user accounts / or whatever operation you want to do.
To make the apps more interactive and lively , you may conside including a wonderful thing called SiganalR, which helps you to get some real time data without continuosly polling the data base/ middle tier very in every n seconds !

Simple Login Attempt counter using MVC 3 and Ajax

Ok so this is driving me nuts. I am probably tired and the answer is looking at me.
public ActionResult _Login(LoginViewModel loginViewModel)
{
if (User.Identity.IsAuthenticated)
{
return JavaScript("window.location=" + "'" + loginViewModel.ReturntUrl + "'");
}
if (ModelState.IsValid)
{
if (Session["loginCount"] == null) //setup the session var with 0 count
{
Session.Add("loginCount", 0);
}
_loginStatus = _authenticationService.Authenticate(loginViewModel.SiteLoginViewModel.EmailAddress,
loginViewModel.SiteLoginViewModel.Password);
if(!_loginStatus.UserExists)
{
ModelState.AddModelError("SiteLoginViewModel.EmailAddress", _loginStatus.ErrorMessage);
return PartialView();
}
// This will only be true if the user types in the correct password
if(!_loginStatus.IsAuthenticated)
{
Session["loginCount"] = (int)Session["loginCount"] + 1;
Response.Write(Session["loginCount"]); // Counter is incremented twice!!!!
//_userService.SetInvalidLoginAttempts(loginViewModel.SiteLoginViewModel.EmailAddress, 1);
ModelState.AddModelError("SiteLoginViewModel.EmailAddress", _loginStatus.ErrorMessage);
return PartialView();
}
// DELETE ANY OPENID Cookies
var openidCookie = new HttpCookie("openid_provider");
if (openidCookie.Value != null)
{
openidCookie.Expires = DateTime.Now.AddDays(-1d);
Response.Cookies.Add(openidCookie);
}
_userService.SetInvalidLoginAttempts(loginViewModel.SiteLoginViewModel.EmailAddress, 0);
SetAuthTicket(loginViewModel.SiteLoginViewModel.EmailAddress, _userService.GetUserId(loginViewModel.SiteLoginViewModel.EmailAddress),
loginViewModel.SiteLoginViewModel.RemeberLogin);
if (!string.IsNullOrEmpty(loginViewModel.ReturntUrl))
{
return JavaScript("window.location=" + "'" + loginViewModel.ReturntUrl + "'");
}
return JavaScript("location.reload(true)");
}
return PartialView();
}
This almost seems that the request is being processed twice however when i step through with the debugger I only see it once. Please ignore the non important parts of the ActionMethod
This looks like you are tying to code for stuff that you automatically get with .Net's Membership provider.
Your first line "User.Identity.IsAuthenticated" looks like you are using part of membership provider but it would seem the rest is trying to code around it.
Also, why are you returning javascript to direct the user's browser to a new URL? Regarless of what .net platform you are on there are plenty of ways to redirect the user's browser without having to return raw javascript, which in my book is REALLY BAD.
##
This fixed the problem and will be removed rather than commented out. Including this twice is very bad obviously :)

SmtpClient.SendAsync blocking my ASP.NET MVC Request

I have a Action that sends a simple email:
[HttpPost, ActionName("Index")]
public ActionResult IndexPost(ContactForm contactForm)
{
if (ModelState.IsValid)
{
new EmailService().SendAsync(contactForm.Email, contactForm.Name, contactForm.Subject, contactForm.Body, true);
return RedirectToAction(MVC.Contact.Success());
}
return View(contactForm);
}
And a email service:
public void SendAsync(string fromEmail, string fromName, string subject, string body, bool isBodyHtml)
{
MailMessage mailMessage....
....
SmtpClient client = new SmtpClient(settingRepository.SmtpAddress, settingRepository.SmtpPort);
client.EnableSsl = settingRepository.SmtpSsl;
client.Credentials = new NetworkCredential(settingRepository.SmtpUserName, settingRepository.SmtpPassword);
client.SendCompleted += client_SendCompleted;
client.SendAsync(mailMessage, Tuple.Create(client, mailMessage));
}
private void client_SendCompleted(object sender, System.ComponentModel.AsyncCompletedEventArgs e)
{
Tuple<SmtpClient, MailMessage> data = (Tuple<SmtpClient, MailMessage>)e.UserState;
data.Item1.Dispose();
data.Item2.Dispose();
if (e.Error != null)
{
}
}
When I send a email, I am using Async method, then my method SendAsync return immediately, then RedirectToAction is called. But the response(in this case a redirect) isnĀ“t sent by ASP.NET until client_SendCompleted is completed.
Here's what I'm trying to understand:
When watching the execution in Visual Studio debugger, the SendAsync returns immediately (and RedirectToAction is called), but nothing happens in the browser until email is sent?
If i put a breakpoint inside client_SendCompleted, the client stay at loading.... until I hit F5 at debugger.
This is by design. ASP.NET will automatically wait for any outstanding async work to finish before finishing the request if the async work was kicked off in a way that calls into the underlying SynchronizationContext. This is to ensure that if your async operation tries to interact with the HttpContext, HttpResponse, etc. it will still be around.
If you want to do true fire & forget, you need to wrap your call in ThreadPool.QueueUserWorkItem. This will force it to run on a new thread pool thread without going through the SynchronizationContext, so the request will then happily return.
Note however, that if for any reason the app domain were to go down while your send was still in progress (e.g. if you changed the web.config file, dropped a new file into bin, the app pool recycled, etc.) your async send would be abruptly interrupted. If you care about that, take a look at Phil Haacks WebBackgrounder for ASP.NET, which let's you queue and run background work (like sending an email) in such a way that will ensure it gracefully finishes in the case the app domain shuts down.
This is an interesting one. I've reproduced the unexpected behaviour, but I can't explain it. I'll keep digging.
Anyway the solution seems to be to queue a background thread, which kind of defeats the purpose in using SendAsync. You end up with this:
MailMessage mailMessage = new MailMessage(...);
SmtpClient client = new SmtpClient(...);
client.SendCompleted += (s, e) =>
{
client.Dispose();
mailMessage.Dispose();
};
ThreadPool.QueueUserWorkItem(o =>
client.SendAsync(mailMessage, Tuple.Create(client, mailMessage)));
Which may as well become:
ThreadPool.QueueUserWorkItem(o => {
using (SmtpClient client = new SmtpClient(...))
{
using (MailMessage mailMessage = new MailMessage(...))
{
client.Send(mailMessage, Tuple.Create(client, mailMessage));
}
}
});
With .Net 4.5.2, you can do this with ActionMailer.Net:
var mailer = new MailController();
var msg = mailer.SomeMailAction(recipient);
var tcs = new TaskCompletionSource<MailMessage>();
mailer.OnMailSentCallback = tcs.SetResult;
HostingEnvironment.QueueBackgroundWorkItem(async ct =>
{
msg.DeliverAsync();
await tcs.Task;
Trace.TraceInformation("Mail sent to " + recipient);
});
Please read this first: http://www.hanselman.com/blog/HowToRunBackgroundTasksInASPNET.aspx
I sent the bug to Microsoft Connect https://connect.microsoft.com/VisualStudio/feedback/details/688210/smtpclient-sendasync-blocking-my-asp-net-mvc-request

Resources