I have some links on my page for which the controllers are yet to be created. I have my custom controller factory like this:
public class MyControllerFactory : DefaultControllerFactory
{
public override IController CreateController(RequestContext requestContext, string controllerName)
{
try
{
IController controller = base.CreateController(requestContext, controllerName);
HttpContext.Current.Items["Controller"] = controller;
return controller;
}
catch { return null; }
}
}
This works fine as long as it can find controller. However I throws yellow screen of death if I return null from my method. How can I gracefully handle this? I want to redirect to some page along with 404 nicely formatted message or maybe show some message such as "In Progress".
Did you try adding this?
[HandleError(ExceptionType = typeof(NullReferenceException), Order = 1, View = "NotFound")]
you will have to add a NotFound view to the shared views folder. Annotate your controller factory with this attribute.
Related
I have a bit of problem
I have an MVC site that is working just fine.
I wanted to have SEO friendly urls so I created custom routing that looks like this
{section}/{group}/{manufacturer}
since it has the same number of fields as the default route
{controller}/{action}/{id}
i created in loop in RouteConfig.cs that goes to database and loops Sections table and creates custom routes like
FOOD/{group}/{manufacturer}
SPORT/{group}/{manufacturer}
CARS/{group}/{manufacturer}
and point it to the Sections controller.
It works just fine. The problem I have is that now i need to rename FOOD to FRESH-FOOD and i want to keep old links to FOOD working.
What would you recommend ? How can I solve this ?
Is there a better way to do route Section instead of custom routes ?
Sounds like this might be a good case for a custom route handler. In the ProcessRequest method below you can check for controller name of "FOOD" and redirect to "FRESH-FOOD" like this:
public class CustomRouteHandler : IRouteHandler
{
public IHttpHandler GetHttpHandler(RequestContext requestContext)
{
return new CustomHttpHandler();
}
}
public class CustomHttpHandler : IHttpHandler
{
public bool IsReusable
{
get
{
return true;
}
}
public void ProcessRequest(HttpContext context)
{
var routeValues = context.Request.RequestContext.RouteData.Values;
var controllerName = context.Request.RequestContext.RouteData.GetRequiredString("controller");
if (controllerName.ToLower() == "food") controllerName = "FRESH-FOOD";
var controller = ControllerBuilder.Current.GetControllerFactory().
CreateController(context.Request.RequestContext, controllerName);
if (controller != null)
{
controller.Execute(context.Request.RequestContext);
}
}
}
When you create your custom routes use the Route constructor overload that takes an IRouteHandler
I'm working with MVC 4 Web API and I have this dummy ValueProvider:
DummyValueProvider.cs
class DummyValueProvider : IValueProvider
{
public DummyValueProvider()
{
}
public bool ContainsPrefix(string prefix)
{
return true;
}
public ValueProviderResult GetValue(string key)
{
return new ValueProviderResult("testing", "testing", System.Globalization.CultureInfo.InvariantCulture);
}
}
class DummyValueProviderFactory : System.Web.Http.ValueProviders.ValueProviderFactory
{
public override IValueProvider GetValueProvider(System.Web.Http.Controllers.HttpActionContext actionContext)
{
return new DummyValueProvider();
}
}
This ValueProvider should return true for any key asked, so it will always supply a value to the model binder when it needs. The ValueProvider is registered in the WebApiConfig like this:
WebApiConfig.cs
config.Services.Add(typeof(ValueProviderFactory), new DummyValueProviderFactory());
The code compiles and runs fine.
I also have this action in the Account API controller:
AccountController.cs
public HttpResponseMessage Register(string foo) { ... }
The action gets called fine when I call it like below:
/register?foo=bar
And foo is filled with bar as expected; but if I call:
/register
The server returns 404 with the message No HTTP resource was found that matches the request URI 'http://localhost:14459/register'.
Also, I put breakpoints inside methods ContainsPrefix() and GetValue(), but they never get triggered.
What am I doing wrong? Shouldn't DummyValueProvider be providing the value testing to parameter foo?
Try this
public HttpResponseMessage Get([ValueProvider(typeof(DummyValueProviderFactory))] string foo) {... }
I higly suggest you to read this recent article to customize Web Api Binding.
Update:
After reading the article the OP was able to discover the solution. It was that using the parameter attribute [ModelBinder] was required for it to work. This was because unless the parameter is annotated, [FromUri] is assumed. Once annotated with [ModelBinder] the registered handlers are executed.
I want to return a HTTP status 404 if invalid arguments are passed to my controller. For example if I have a controller that looks like:
public ActionResult GetAccount(int id)
{
...
}
Then I want to return a 404 if say urls such as these are encountered:
/GetAccount
/GetAccount/notanumber
i.e. I want to trap the ArgumentException that is thrown.
I know I could use a nullable type:
public ActionResult GetAccount(int? id)
{
if(id == null) throw new HttpException(404, "Not found");
}
But that's pretty icky and repetitious.
I was hoping I could add this to my controllers where necessary:
[HandleError(View="Error404", ExceptionType = typeof(ArgumentException))]
public class AccountsController : Controller
{
public ActionResult GetAccount(int id)
{
...
}
}
But that doesn't appear to work well.
I saw this post and this answer which nearly solves my problem:
In that answer an abstract BaseController is created from which you derive all your other controllers from:
public abstract class MyController : Controller
{
#region Http404 handling
protected override void HandleUnknownAction(string actionName)
{
// If controller is ErrorController dont 'nest' exceptions
if (this.GetType() != typeof(ErrorController))
this.InvokeHttp404(HttpContext);
}
public ActionResult InvokeHttp404(HttpContextBase httpContext)
{
IController errorController = ObjectFactory.GetInstance<ErrorController>();
var errorRoute = new RouteData();
errorRoute.Values.Add("controller", "Error");
errorRoute.Values.Add("action", "Http404");
errorRoute.Values.Add("url", httpContext.Request.Url.OriginalString);
errorController.Execute(new RequestContext(
httpContext, errorRoute));
return new EmptyResult();
}
#endregion
}
This works great at handling unknown actions with a 404 but doesn't allow me to handle invalid data as a 404.
Can I safely override Controller.OnException(ExceptionContext filterContext) like this:
protected override void OnException(ExceptionContext filterContext)
{
if(filterContext.Exception.GetType() == typeof(ArgumentException))
{
filterContext.ExceptionHandled = true;
this.InvokeHttp404(filterContext.HttpContext);
}
else
{
base.OnException(filterContext);
}
}
On the surface it seems to work, but am I storing up any problems by doing this?
Is this semantically correct thing to do?
Best way? Action method selector attribute!
To actually avoid nullable method arguments I suggest that you write an Action Method Selector attribute that will actually only match your action method when id is supplied. It won't say that argument wasn't supplied but that it couldn't match any action methods for the given request.
I would call this action selector RequireRouteValuesAttribute and would work this way:
[RequireRouteValues("id")]
public ActionResult GetAccount(int id)
{
...
}
Why is this the best solution for your problem?
If you look at your code you'd like to return a 404 on actions that match name but parameter binding failed (either because it wasn't supplied or any other reason). Your action so to speak requires particular action parameter otherwise a 404 is returned.
So when adding action selector attribute adds the requirement on the action so it has to match name (this is given by MVC) and also require particular action parameters. Whenever id is not supplied this action is not matched. If there's another action that does match is not the issue here because that particular action will get executed. The main thing is accomplished. Action doesn't match for invalid route request and a 404 is returned instead.
There's an app code for that!
Check my blog post that implements this kind of attribute that you can use out of the box. It does exactly what you're after: it won't match your action method if route data provided doesn't have all required values.
Disclaimer: this does not cover all the cases
For urls in your examples, returning 404 can be done in single line. Just add route constraint for id parameter.
routes.MapRoute(
"Default", // Route name
"{controller}/{action}/{id}", // URL with parameters
new { controller = "Home", action = "Index" }, // Parameter defaults
new { id = #"\d+" } // restrict id to be required and numeric
);
And that's all. Now any matching url that has no id or id is not numeric, autimatically triggers not found error (for which there are plenty of ways to handle, one in your example, another by using custom HandleErrorAttribute, etc). And you can use non-nullable int parameters on your actions.
I managed to get this working by adding this route at the end of all routes:
routes.MapRoute("CatchAllErrors", "{*url}",
new { controller = "Error", action = "NotFound" }
);
Note: First I followed this: How can I properly handle 404 in ASP.NET MVC?
I am creating an ActionResult in ASP.Net MVC to serve images. With Session state enabled, IIS will only handle one request at a time from the same user. (This is true not just in MVC.)
Therefore, on a page with multiple images calling back to this Action, only one image request can be handled at a time. It's synchronous.
I'd like this image Action to be asynchronous -- I'd like multiple image requests to each execute without needing the previous one to complete. (If the images were just static files, IIS would serve them up this way.)
So, I'd like to disable Session just for calls to that Action, or to specify that certain requests do not have Session state. Anyone know how this is done in MVC? Thanks!
If anyone is in the situation I was in, where your image controller actually needs read only access to the session, you can put the SessionState attribute on your controller
[SessionState(SessionStateBehavior.ReadOnly)]
See http://msdn.microsoft.com/en-us/library/system.web.mvc.sessionstateattribute.aspx for more info.
Thanks to https://stackoverflow.com/a/4235006/372926
Rather than implementing an action filter for this, why don't you implement a RouteHandler?
Here's the deal - IRouteHandler has one method - GetHttpHandler. When you make an ASP.Net MVC request to a controller, by default the routing engine handles the request by creating a new instance of MvcRouteHandler, which returns an MvcHandler. MvcHandler is an implementation of IHttpHandler which is marked with the (surprise!) IRequiresSessionState interface. This is why a normal request uses Session.
If you follow my blog post on how to implement a custom RouteHandler (instead of using MvcRouteHandler) for serving up images - you can skip returning a session-tagged IHttpHandler.
This should free IIS from imposing synchronicity on you. It would also likely be more performant because it's skipping all the layers of the MVC code dealing with filters.
I also came across the same problem and after doing R&D this link worked for me
Reference:
https://techatfingers.wordpress.com/2016/06/14/session-state-on-action/
Create custom Attribute
Override the “GetControllerSessionBehavior” method present in class DefaultControllerFactory.
Register it in global.aspx
1> Create custom Attribute
public sealed class ActionSessionStateAttribute : Attribute
{
public SessionStateBehavior SessionBehavior { get; private set; }
public ActionSessionStateAttribute(SessionStateBehavior sessionBehavior)
{
SessionBehavior = sessioBehavior;
}
}
2. Override
public class SessionControllerFactory : DefaultControllerFactory
{
protected override SessionStateBehavior GetControllerSessionBehavior(RequestContext requestContext, Type controllerType)
{
if (controllerType == null)
return SessionStateBehavior.Default;
var actionName = requestContext.RouteData.Values["action"].ToString();
Type typeOfRequest=requestContext.HttpContext.Request.RequestType.ToLower() =="get"?typeof(HttpGetAttribute):typeof(HttpPostAttribute);
// [Line1]
var cntMethods = controllerType.GetMethods()
.Where(m =>
m.Name == actionName &&
( ( typeOfRequest == typeof(HttpPostAttribute) &&
m.CustomAttributes.Where(a => a.AttributeType == typeOfRequest).Count()>0
)
||
( typeOfRequest == typeof(HttpGetAttribute) &&
m.CustomAttributes.Where(a => a.AttributeType == typeof(HttpPostAttribute)).Count() == 0
)
)
);
MethodInfo actionMethodInfo = actionMethodInfo = cntMethods != null && cntMethods.Count() == 1 ? cntMethods.ElementAt(0):null;
if (actionMethodInfo != null)
{
var sessionStateAttr = actionMethodInfo.GetCustomAttributes(typeof(ActionSessionStateAttribute), false)
.OfType<ActionSessionStateAttribute>()
.FirstOrDefault();
if (sessionStateAttr != null)
{
return sessionStateAttr.Behavior;
}
}
return base.GetControllerSessionBehavior(requestContext, controllerType);
}
3. Register class in Global.asax
public class MvcApplication : System.Web.HttpApplication
{
protected void Application_Start()
{
// --- other code ---
ControllerBuilder.Current.SetControllerFactory(typeof(SessionControllerFactory));
}
}
Try serving the images from another domain. So something like images.mysite.com.
This will provide you two benefits: One, sessions are tracked by a cookie, so images.mysite.com won't have the cookie. Two, it will give you an additional two concurrent requests to retrieve images.
Have you considered setting up a HttpHandler to serve up your images?
SessionState attribute is quite helpful if u use mvc3. How to achieve this with mvc2 needs a little more coding.
Idea is to tell the asp.net that specific request wont use session object.
So, Create a custom route handler for specific requests
public class CustomRouteHandler : IRouteHandler
{
public System.Web.IHttpHandler GetHttpHandler(RequestContext requestContext)
{
requestContext.HttpContext.SetSessionStateBehavior(System.Web.SessionState.SessionStateBehavior.ReadOnly);
return new MvcHandler(requestContext);
}
}
SessionStateBehavior enum has 4 members, you should use "disabled" or "readonly" modes to get async behavior.
After creating this custom route handler, be sure that your specific requests goes through this handler. This can be done via defining new routes at Global.asax
routes.Add("Default", new Route(
"{controller}/{action}",
new RouteValueDictionary(new { controller = "Home", action = "Index"}),
new CustomRouteHandler()
));
Adding this route makes all your requests to be handled by your custom route handler class. You can make it specific by defining different routes.
Change DefaultCOntrollerFactory to custom ControllerFactory class. Default Controller.TempDataProvider use SessionStateTempDataProvider. you can change it.
1.Set web.config/system.web/sessionState:mode="Off".
2.create DictionaryTempDataProvider class.
public class DictionaryTempDataProvider : ITempDataProvider
{
public IDictionary<string, object> LoadTempData(ControllerContext controllerContext)
{
return new Dictionary<string, object>();
}
public void SaveTempData(ControllerContext controllerContext, IDictionary<string, object> values)
{
}
}
3.Create DictionaryTempDataControllerFactory
public class DictionaryTempDataControllerFactory : DefaultControllerFactory
{
public override IController CreateController(System.Web.Routing.RequestContext requestContext, string controllerName)
{
var controller = base.CreateController(requestContext, controllerName) as Controller;
if (controller!=null)
controller.TempDataProvider = new DictionaryTempDataProvider();
return controller;
}
}
4.In global.asax.cs Apprication_Start event set DictionaryTempDataControllerFactory.
protected void Application_Start()
{
RegisterRoutes(RouteTable.Routes);
ControllerBuilder.Current.SetControllerFactory(
new DictionaryTempDataControllerFactory()
);
}
On our server, IIS doesn't even know about sessions - it's the ASP.NET stack that handles one request per session at a time. Static files, like images, are never affected.
Is it possible that your ASP.NET app is serving the files instead of IIS?
Create new Controller
Decorate controler with [SessionState(SessionStateBehavior.Disabled)]
Refactor code you want seesion stated disabled for to that controller
I would to share my solution for disable ASP.NET Session for an specific request (in my case, a WCF Service) using an HttpModule:
public class AspNetSessionFilterModule : IHttpModule
{
public void Init(HttpApplication context)
{
context.PostMapRequestHandler += OnPostMapRequestHandler;
}
private void OnPostMapRequestHandler(object sender, EventArgs e)
{
var context = (sender as HttpApplication).Context;
DisableSessionForSomeRequests(context);
}
private void DisableSessionForSomeRequests(HttpContext context)
{
if ("~/Services/MyService.svc".Equals(context.Request.AppRelativeCurrentExecutionFilePath, StringComparison.InvariantCultureIgnoreCase))
{
context.SetSessionStateBehavior(System.Web.SessionState.SessionStateBehavior.Disabled);
}
}
public void Dispose()
{ }
}
I have the pattern User/{domain}/{username} set up via Routing. Everything works except for one thing. I can't figure out how to get the domain and username variables passed to my redirected page. Below is my GetHttpHandler method from my IRouteHandler implementation.
public IHttpHandler GetHttpHandler(RequestContext requestContext)
{
string basePath;
basePath = "~/UserPage.aspx";
string domain = requestContext.RouteData.GetRequiredString("domain");
string username = requestContext.RouteData.GetRequiredString("username");
string virtualPath =
string.Format(basePath + "?domain={0}&username={1}", domain, username);
return (Page)BuildManager.CreateInstanceFromVirtualPath(virtualPath, typeof(Page));
}
I get the error from the last line of code:
UserPage.aspx?domain=SOMEDOMAIN&username=SOMEUSER is not a valid virtual path.
So how are you supposed to pass variables to the target page? what am I missing?
I think I solved this one myself.
Found this loop
foreach (KeyValuePair<string, object> token in requestContext.RouteData.Values)
{
requestContext.HttpContext.Items.Add(token.Key, token.Value);
}
from http://www.codethinked.com/post/2008/08/20/Exploring-SystemWebRouting.aspx
Its like the 4th code sample down.
UPDATE:
Not sure if this will work... requestContext.HttpContext seems to be "readonly". Back to the drawing board.
UPDATE 2:
Looks like this will work if you add in a reference to System.Web.Abstractions
Started mucking around with things and saw the IHttpHandler interface provides the RequestContext to the GetHttpHandler method.
So, I modified my base page class (I always put a layer between System.Web.UI.Page and my own pages, calling it BasePage or similar just for the purpose). So I added a public property on PVBasePage to receive a RequestContext object.
public RequestContext RequestContext { get; set; }
Then, my Routing class code is as follows:
IHttpHandler IRouteHandler.GetHttpHandler(RequestContext requestContext)
{
// create the page object as my own page...
var page = BuildManager.CreateInstanceFromVirtualPath(VirtualPath
, typeof(PVBasePage)) as PVBasePage;
// pass in the request context
page.RequestContext = requestContext;
// return this page in the form of a IHttpHandler
return page as IHttpHandler;
}
So instead of, as in the sample code, creating the instance directly as the IHttpHandler, I create it as my own page. Set the request context property, and then return the page to the caller AS a IHttpHandler.
Tested and it works. WOO HOO!
Then in the instance page, you can hit the RequestContext.GetValues collection to read out your passed in parameters.
HTH
#B.Tyndall
I just got this working with a solution similar to yours.
found at: http://msmvps.com/blogs/luisabreu/archive/2008/03/12/using-the-routing-mvc-api-with-classic-asp-net.aspx
foreach (var aux in requestContext.RouteData.Values)
{
HttpContext.Current.Items[aux.Key] = aux.Value;
}
So in effect you're no longer using the Request.QueryString but instead Context.Items collection
HttpContext.Current.Items["RouteName"]
or
Context.Items["RouteName"]
It appears as though other are also taking the route (no pun intended) of putting the parameters in the context Items collection.
http://bbits.co.uk/blog/archive/2008/05/19/using-asp.net-routing-independent-of-mvc---passing-parameters-to.aspx
I combined a couple of these approaches for pages that have a specific parameter, I created a UserNameRouteHandler for pages that accept that type of parameter. In my PageBase class I checked the context items for that parameter and then set a property so that my pages that inherit from PageBase can use it.
public class UserNameRouteHandler : IRouteHandler
{
#region Implementation of IRouteHandler
public IHttpHandler GetHttpHandler(RequestContext requestContext)
{
string pageName = requestContext.RouteData.GetRequiredString("PageName");
string employeeUserName = requestContext.RouteData.GetRequiredString("UserName");
if(!string.IsNullOrEmpty(employeeUserName))
{
requestContext.HttpContext.Items["UserName"] = employeeUserName;
}
pageName = pageName.ToLower() == "home" ? "default" : pageName;
string virtualPath = string.Format("~/{0}.aspx", pageName);
return (Page)BuildManager.CreateInstanceFromVirtualPath(virtualPath, typeof(Page));
}
#endregion
}
And in my OnLoad of PageBase I set the property to pages that need it can have it...definitely looking for a more elegant solution though.
protected override void OnLoad(EventArgs e)
{
if (!IsPostBack)
{
if (Context.Items["UserName"] != null)
{
EmployeeUserName = Context.Items["UserName"].ToString();
}
}
base.OnLoad(e);
}