ASP.NET MVC how to implement link which returns to previous page? - asp.net-mvc

Title said it all.
Some context:
I got a search mechanism - search view, search results view and a details view (which represents one item of results, like a formview in webforms). I want a link in details view, which would return user to search results view.
Ideas:
Just read about TempData, but i guess that wouldn't help, cause user might call some actions before he wants to return.
Session might work, but I'm not sure how exactly i should handle it.
I don't want to use javascript to accomplish this.
Edit:
Seems that i'll stick with eu-ge-ne`s solution. Here's result:
#region usages
using System.Web.Mvc;
using CompanyName.UI.UIApp.Infrastructure.Enums;
#endregion
namespace CompanyName.UI.UIApp.Infrastructure.Filters
{
/// <summary>
/// Apply on action method to store URL of request in session
/// </summary>
public class RememberUrlAttribute : ActionFilterAttribute
{
public override void OnActionExecuting
(ActionExecutingContext filterContext)
{
var httpContext = filterContext.HttpContext;
if (httpContext.Request.RequestType == "GET"
&& !httpContext.Request.IsAjaxRequest())
{
SessionManager
.Save(SessionKey.PreviousUrl,
SessionManager.Get(SessionKey.CurrentUrl) ??
httpContext.Request.Url);
SessionManager
.Save(SessionKey.CurrentUrl,
httpContext.Request.Url);
}
}
}
}
Btw, how does .IsAjaxRequest() method works? It understands only MS AJAX or it's smarter than that?

I think you need something like this custom filter (not tested - have no VS at the moment):
public class PrevUrlAttribute : ActionFilterAttribute
{
public override void OnActionExecuting(ActionExecutingContext filterContext)
{
var httpContext = filterContext.HttpContext;
var session = filterContext.HttpContext.Session;
if (httpContext.Request.RequestType == "GET"
&& !httpContext.Request.IsAjaxRequest())
{
session["PrevUrl"] = session["CurUrl"] ?? httpContext.Request.Url;
session["CurUrl"] = httpContext.Request.Url;
}
}
}

You can examine the HTTP Referrer header to retrieve the previous URL.
Of course, you'll have to handle gracefully just in case the user does not pass in this value.

Yo
:)

Related

Check if current request url is controller index

Does somebody know a way of checking if the current request its URL is targeted to a controller its index page?
In my application I have about 30 controllers with each an index page. I have an ActionFilter which sets a cookie on each request in its OnActionExecuting event. However I want it to be set only when the user visits an index page. I'm aware that all of the following URL's will return the index;
http://xxxx/controllerName/index
http://xxxx/controllerName/
http://xxxx/controllerName
Anyone know the best way of checking this?
Before anyone asks, the ActionFilter I'm using is the following:
public class RefreshDetectFilter : IActionFilter
{
public void OnActionExecuting(ActionExecutingContext filterContext)
{
var cookie = filterContext.HttpContext.Request.Cookies["RefreshFilter"];
filterContext.RouteData.Values["IsRefreshed"] = cookie != null && cookie.Value == filterContext.HttpContext.Request.Url.ToString();
}
public void OnActionExecuted(ActionExecutedContext filterContext)
{
filterContext.HttpContext.Response.SetCookie(new HttpCookie("RefreshFilter", filterContext.HttpContext.Request.Url.ToString()));
}
}
Kind regards and thanks in advance,
Yannick
You can get the current Action like this, regardless of the URL containing the action name or not:
filterContext.RouteData.Values["action"]

Best approach to don't request same info over and over

On my controller I have it inherit a MainController and there I override the Initialize and the OnActionExecuting.
Here I see what is the URL and by that I can check what Client is it, but I learned that for every Method called, this is fired up again and again, even a simple redirectToAction will fire the Initialization of the same controller.
Is there a better technique to avoid this repetition of database call? I'm using Entity Framework, so it will take no time to call the DB as it has the result in cache already, but ... just to know if there is a better technique now in MVC3 rather that host the variables in a Session Variable
sample code
public class MyController : MainController
{
public ActionResult Index()
{
return View();
}
}
public class MainController : Controller
{
public OS_Clients currentClient { get; set; }
protected override void Initialize(System.Web.Routing.RequestContext requestContext)
{
// get URL Info
string url = requestContext.HttpContext.Request.Url.AbsoluteUri;
string action = requestContext.RouteData.GetRequiredString("action");
string controller = requestContext.RouteData.GetRequiredString("controller");
object _clientUrl = requestContext.RouteData.Values["cliurl"];
if (_clientUrl != null && _clientUrl.ToString() != "none")
{
// Fill up variables
this.currrentClient = db.FindClientById(_clientUrl.ToString());
}
base.Initialize(requestContext);
}
protected override void OnActionExecuting(ActionExecutingContext filterContext)
{
// based on client and other variables, redirect to Disable or Login Actions
// ... more code here like:
// filterContext.Result = RedirectToAction("Login", "My");
base.OnActionExecuting(filterContext);
}
}
is it still best to do as:
public OS_Clients currentClient {
get {
OS_Clients _currentClient = null;
if (Session["CurrentClient"] != null)
_currentClient = (OS_Clients)Session["CurrentClient"];
return _currentClient;
}
set {
Session["CurrentClient"] = value;
}
}
It seems that you dealing with application security in that case I would suggest to create Authorization filter, which comes much early into the action. You can put your permission checking code over there and the framework will automatically redirect the user to login page if the permission does not meet AuthorizeCore.
Next, if the user has permission you can use the HttpContext.Items as a request level cache. And then you can create another ActionFilter and in action executing or you can use the base controller to get the user from the Httpcontext.items and assign it to controller property.
If you are using asp.net mvc 3 then you can use the GlobalFilters to register the above mentioned filters instead of decorating each controller.
Hope that helps.
In your base controller, you need to cache the result of the first call in a Session variable.
This makes sure the back-end (DB) is not called unnecessarily, and that the data is bound to the user's Session instead of shared across users, as would be the case with the Application Cache.

Two step authentication in MVC?

We have an MVC app which has a custom forms authentication view/controller. The controller will verify things and then do a FormsAuthentication.RedirectFromLoginPage call.
At this point in the Global.asax we'll receive a Application_OnAuthenticateRequest call from where we'll get their Context.User information and make another call to gather information relevant to this account which we then store in their Context.User & System.Threading.Thread.CurrentPrincipal. We also do a little caching of this information since in our system retrieving what we need is expensive which leads to cache invalidation & re-retrieval of this information.
It seems a bit odd at this point that we've got these separated into separate calls. I'm almost wondering if the Login controller shouldn't be gathering the details as part of its authentication check and storing them. Then the Application_OnAuthenticateRequest can only worry about if the cache needs to be invalidated and the users details re-retrieved.
Or maybe there is some other way of handling this I don't even know about..?
You can do what you want in MVC by leveraging RedirectToRouteResult and a custom cache updating ActionFilter. This is called the PRG (Post-Redirect-Get) pattern. You are actually already doing this, but it gets a little confused, because what you are doing is a cross between the classic ASP.NET way of doing things and the MVC way of doing things. There's nothing wrong with your initial approach (provided it is working correctly), but to do the same sort of thing and have more control and understanding of how it works in the scheme of things you could do something like:
public class AuthenticationController :Controller
{
[HttpPost]
public RedirectToRouteResult Login(string username, string password)
{
//authenticate user
//store authentication info in TempData like
bool authenticated = true|false; // do your testing
if(authenticated)
{
TempData["MustUpdateCache"] = true | false;
return RedirectToAction("LoginSuccess", new{userId = membershipUser.UserId});
}
else
{
TempData["MustUpdateCache"] = true | false;
return RedirectToAction("Login");
}
}
[HttpGet, UpdateCache]
public ActionResult LoginSuccess(Guid userId, string url)
{
HttpContext.User = LoadUser(userId);
return View();
}
[HttpGet, UpdateCache]
public ViewResult Login()
{
return View();
}
}
public class UpdateCacheAttribute:ActionFilterAttribute
{
public override void OnResultExecuting(ResultExecutingContext filterContext)
{
var tempData = filterContext.Controller.TempData;
if (tempData.ContainsKey("MustUpdateCache") && (bool)tempData["MustUpdateCache"])
{
UpdateCache(filterContext);
}
}
void UpdateCache(ControllerContext controllerContext)
{
//update your cache here
}
}

Mock a web service used in an action filter

I have an external-to-my-solution web service that I'm using in an ActionFilter. The action filter grabs some basic data for my MasterPage. I've gone back and forth between using an action filter and extending the base controller class, and decided the action filter was the best approach. Then I started unit testing (Yeah, yeah TDD. Anyway... :D )
So I can't mock (using Moq, btw) a web service in an action filter because I can't inject my mock WS into the action filter, since action filters don't take objects as params. Right? At least that's what I seem to have come to.
Any ideas? Better approaches? I'm just trying to return a warning to the user that if the web service is unavailable, their experience might be limited.
Thanks for any help!
namespace MyProject.ActionFilters
{
public class GetMasterPageData : ActionFilterAttribute
{
public ThatWS ws = new ThatWS();
public override void OnActionExecuting(ActionExecutingContext filterContext)
{
HttpContextBase context = filterContext.HttpContext;
try {
DoStuff();
}
catch ( NullReferenceException e ) {
context.Session["message"] = "There is a problem with the web service. Some functionality will be limited.";
}
}
}
}
Here's a quick and dirty approach:
public class GetMasterPageData : ActionFilterAttribute
{
public Func<ISomeInterface> ServiceProvider = () => new ThatWS();
public override void OnActionExecuting(ActionExecutingContext filterContext)
{
var result = ServiceProvider().SomeMethod();
...
}
}
And in your unit test you could instantiate the action filter and replace the ServiceProvider public field with some mocked object:
objectToTest.ServiceProvider = () => new SomeMockedObject();
Of course this approach is not as clean as the one suggested by #Ryan in the comments section but it could work in some situations.

Is there a way to maintain IsAjaxRequest() across RedirectToAction?

If you don't want any context or an example of why I need this, then skip to The question(s) at the bottom!
In a bid to keep things tidy I initially built my application without JavaScript. I am now attempting to add a layer of unobtrusive JavaScript on the top of it.
In the spirit of MVC I took advantage of the easy routing and re-routing you can do with things like RedirectToAction().
Suppose I have the following URL to kick off the sign up process:
http://www.mysite.com/signup
And suppose the sign up process is two steps long:
http://www.mysite.com/signup/1
http://www.mysite.com/signup/2
And suppose I want, if JavaScript is enabled, the sign up form to appear in a dialog box like ThickBox.
If the user leaves the sign up process at step 2, but later clicks the "sign up" button, I want this URL:
http://www.mysite.com/signup
To perform some business logic, checking the session. If they left a previous sign up effort half way through then I want to prompt them to resume that or start over.
I might end up with the following methods:
public ActionResult SignUp(int? step)
{
if(!step.HasValue)
{
if((bool)Session["SignUpInProgress"] == true)
{
return RedirectToAction("WouldYouLikeToResume");
}
else
{
step = 1;
}
}
...
}
public ActionResult WouldYouLikeToResume()
{
if(Request.IsAjaxRequest())
{
return View("WouldYouLikeToResumeControl");
}
return View();
}
The logic in WouldYouLikeToResume being:
If it's an AJAX request, only return the user control, or "partial", so that the modal popup box does not contain the master page.
Otherwise return the normal view
This fails, however, because once I redirect out of SignUp, IsAjaxRequest() becomes false.
Obviously there are very easy ways to fix this particular redirect, but I'd like to maintain the knowledge of the Ajax request globally to resolve this issue across my site.
The question(s):
ASP.NET MVC is very, very extensible.
Is it possible to intercept calls to RedirectToAction and inject something like "isAjaxRequest" in the parameters?
OR
Is there some other way I can detect, safely, that the originating call was an AJAX one?
OR
Am I going about this the completely wrong way?
As requested by #joshcomley, an automated answer using the TempData approach:
This assumes that you have a BaseController and your controllers are inheriting from it.
public class AjaxianController : /*Base?*/Controller
{
private const string AjaxTempKey = "__isAjax";
public bool IsAjax
{
get { return Request.IsAjaxRequest() || (TempData.ContainsKey(AjaxTempKey)); }
}
protected override RedirectResult Redirect(string url)
{
ensureAjaxFlag();
return base.Redirect(url);
}
protected override RedirectToRouteResult RedirectToAction(string actionName, string controllerName, System.Web.Routing.RouteValueDictionary routeValues)
{
ensureAjaxFlag();
return base.RedirectToAction(actionName, controllerName, routeValues);
}
protected override RedirectToRouteResult RedirectToRoute(string routeName, System.Web.Routing.RouteValueDictionary routeValues)
{
ensureAjaxFlag();
return base.RedirectToRoute(routeName, routeValues);
}
private void ensureAjaxFlag()
{
if (IsAjax)
TempData[AjaxTempKey] = true;
else if (TempData.ContainsKey(AjaxTempKey))
TempData.Remove(AjaxTempKey);
}
}
To use this, make your controller inherit from AjaxianController and use the "IsAjax" property instead of the IsAjaxRequest extension method, then all redirects on the controller will automatically maintain the ajax-or-not flag.
...
Havn't tested it though, so be wary of bugs :-)
...
Another generic approach that doesn't require using state that I can think of may requires you to modify your routes.
Specifically, you need to be able to add a generic word into your route, i.e.
{controller}/{action}/{format}.{ajax}.html
And then instead of checking for TempData, you'd check for RouteData["ajax"] instead.
And on the extension points, instead of setting the TempData key, you add "ajax" to your RouteData instead.
See this question on multiple format route for more info.
This worked for me.
Please note that this doesn't require any session state which is a potential concurrency issue:
protected override void OnActionExecuted(ActionExecutedContext filterContext)
{
base.OnActionExecuted(filterContext);
if (this.Request.IsAjaxRequest)
{
if (filterContext.Result is RedirectToRouteResult)
{
RedirectToRouteResult rrr = (RedirectToRouteResult)filterContext.Result;
rrr.RouteValues.Add("X-Requested-With",Request.Params["X-Requested-With"]);
}
}
}
}
Perhaps you can add a AjaxRedirected key in the TempData property before doing the redirection?
One way to transfer state is to add an extra route parameter i.e.
public ActionResult WouldYouLikeToResume(bool isAjax)
{
if(isAjax || Request.IsAjaxRequest())
{
return PartialView("WouldYouLikeToResumeControl");
}
return View();
}
and then in the Signup method:
return RedirectToAction("WouldYouLikeToResume", new { isAjax = Request.IsAjaxRequest() });
// Don't forget to also set the "ajax" parameter to false in your RouteTable
// So normal views is not considered Ajax
Then in your RouteTable, default the "ajax" parameter to false.
Or another way to go would be override extension points in your BaseController (you do have one, right?) to always pass along the IsAjaxRequest state.
..
The TempData approaches are valid too, but I'm a little allergic of states when doing anything that looks RESTful :-)
Havn't tested/prettify the route though but you should get the idea.
I would just like to offer what I believe is a MUCH better answer than the current accepted one.
Use this:
public class BaseController : Controller
{
private string _headerValue = "X-Requested-With";
protected override void OnActionExecuting(ActionExecutingContext filterContext)
{
var ajaxHeader = TempData[_headerValue] as string;
if (!Request.IsAjaxRequest() && ajaxHeader != null)
Request.Headers.Add(_headerValue, ajaxHeader);
}
protected override void OnActionExecuted(ActionExecutedContext filterContext)
{
base.OnActionExecuted(filterContext);
if (Request.IsAjaxRequest() && IsRedirectResult(filterContext.Result))
TempData[_headerValue] = Request.Headers[_headerValue];
}
private bool IsRedirectResult(ActionResult result)
{
return result.GetType().Name.ToLower().Contains("redirect");
}
}
Then make all your controllers inherit from this.
What it does:
Before an action executes this checks to see if there is a value in TempData. If there is then it manually adds its value to the Request object's header collection.
After an action executes it checks if the result was a redirect. If it was a redirect and the request was an Ajax Request before this action was hit then it reads the value of the custom ajax header that was sent and stores it in temp data.
This is better because of two things.
It is shorter and cleaner.
It adds the request header to the Request object after reading the temp data. This allows Request.IsAjaxRequest() to work normally. No calling a custom IsAjax property.
Credit to: queen3 for his question containing this solution. I did modify it to clean it up a bit but it is his solution originally.
The Problem is in the Client-Cache.
To overcome this, just add a cachebreaker
like "?_=XXXXXX" to Location Url in the 302 Response.
Here is my working Filter. Regisiter it in the GlobalFilter Collection.
I added the Location Header to the Redirected Response, so the client script can get the destination url, in the ajax call. (for Google-Analytics)
public class PNetAjaxFilterAttribute : ActionFilterAttribute
{
public override void OnActionExecuting(ActionExecutingContext filterContext)
{
var request = filterContext.HttpContext.Request;
if(request.QueryString["_"] == "ajax")
{
filterContext.HttpContext.Request.Headers["X-Requested-With"] = "XMLHttpRequest";
request.QueryString.Remove("_");
}
}
public override void OnResultExecuted(ResultExecutedContext filterContext)
//public override void OnResultExecuting(ResultExecutingContext filterContext)
{
var context = filterContext.HttpContext;
if (!context.Request.IsAjaxRequest())
return;
var request = context.Request;
String noCacheQuery = String.Empty;
if (request.HttpMethod == "GET")
{
noCacheQuery = request.QueryString["_"];
}
else if (context.Response.IsRequestBeingRedirected)
{
var pragma = request.Headers["Pragma"] ?? String.Empty;
if (pragma.StartsWith("no-cache", StringComparison.OrdinalIgnoreCase))
{
noCacheQuery = DateTime.Now.ToUnixTimestamp().ToString();
}
else
{
//mode switch: one spezial cache For AjaxResponse
noCacheQuery = "ajax";
}
}
if (!String.IsNullOrEmpty(noCacheQuery))
{
if (context.Response.IsRequestBeingRedirected)
{
var location = context.Response.RedirectLocation;
if (location.Contains('?'))
location += "&_=" + noCacheQuery;
else
location += "?_=" + noCacheQuery;
context.Response.RedirectLocation = location;
}
else
{
var url = new UriBuilder(request.Url);
if (url.Port == 80 && url.Scheme == Uri.UriSchemeHttp)
url.Port = -1;
else if(url.Port == 443 && url.Scheme == Uri.UriSchemeHttps)
url.Port = -1;
if(!String.IsNullOrEmpty(url.Query))
url.Query = String.Join("&", url.Query.Substring(1).Split('&').Where(s => !s.StartsWith("_=")));
context.Response.AppendHeader("Location", url.ToString());
}
}
}
}
And here the jQuery:
var $form = $("form");
var action = $form.attr("action");
var $item = $("body");
$.ajax({
type: "POST",
url: action,
data: $form.serialize(),
success: function (data, status, xhr) {
$item.html(data);
var source = xhr.getResponseHeader('Location');
if (source == null) //if no redirect
source = action;
$(document).trigger("partialLoaded", { source: source, item: $item });
}
});

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