I am using ASP.NET MVC 4
I want to trace or handle Exception globally.
1.Which is handled by user code?
2.Which is not handled by user code?
both the type
how is it possible ?
Global error handling:
public class MvcApplication : System.Web.HttpApplication
{
protected void Application_Error(object sender, EventArgs e)
{
Exception exception = Server.GetLastError();
Server.ClearError();
Response.Redirect("/Home/Error");
}
}
Or override OnException method:
public class HomeController : Controller
{
protected override void OnException(ExceptionContext filterContext)
{
Exception ex = filterContext.Exception;
filterContext.ExceptionHandled = true;
var model = new HandleErrorInfo(filterContext.Exception, "Controller","Action");
filterContext.Result = new ViewResult()
{
ViewName = "Error",
ViewData = new ViewDataDictionary(model)
};
}
}
http://www.codeguru.com/csharp/.net/net_asp/mvc/handling-errors-in-asp.net-mvc-applications.htm
Shows different ways of handling errors globally. Setting a global exception handling filter is the usual.
GlobalFilters.Filters.Add(new SpecialHandleErrorAttributeCreatedByYou());
You would derive a new Attribute from HandleErrorAttribute and put your logic in there, overriding the OnException method.
public override void OnException(ExceptionContext filterContext)
However this will not show you exceptions that are handled by other code. That is the point, they are handled so they do not continue to bubble up the stack. You would have to put code in each of those catch blocks to either do what you want.
Yes it is possible you can override. HandleErrorAttribute
And register it globally
public static void RegisterGlobalFilters(GlobalFilterCollection filters)
{
filters.Add(YourNewHandler());
...
}
Related
Currently my product page URL is like
http://www.localhost:80/products/default.aspx?code=productCode
I want to access product page with
http://www.localhost:80/productCode
I have used HTTP module for this.
public class UrlRewritingModule : IHttpModule
{
public void Dispose()
{
}
public void Init(HttpApplication context)
{
context.PreRequestHandlerExecute += new EventHandler(context_PreRequestHandlerExecute);
context.AuthorizeRequest += new EventHandler(context_AuthorizeRequest);
}
void context_AuthorizeRequest(object sender, EventArgs e)
{
HttpContext context = ((HttpApplication)sender).Context;
if (some condition)
{
context.RewritePath(url);
}
}
void context_PreRequestHandlerExecute(object sender, EventArgs e)
{
//We set back the original url on browser
HttpContext context = ((HttpApplication)sender).Context;
if (context.Items["originalUrl"] != null)
{
context.RewritePath((string)context.Items["originalUrl"]);
}
}
}
I have register it in web.config and it is working fine. But when I deploy it in IIS that session and application variables are not throwing null referent Exceptions.
Can anyone help me?
Edit: Do it require extra code to access session/ Application variable for rewritten URLs
?
Have you tried using HTTPContext.Current?
I was able to solve issue (accessing session and application variables in subsequent pages rewritten by custom handler) by adding runAllManagedModulesForAllRequests="true" attribute in modules in web.config.
Why session is null in this even if i set:
public class HelperClass
{
public AtuhenticatedUser f_IsAuthenticated(bool _bRedirect)
{
HttpContext.Current.Session["yk"] = DAO.context.GetById<AtuhenticatedUser>(1);
if (HttpContext.Current.Session["yk"] == null)
{
if (_bRedirect)
{
HttpContext.Current.Response.Redirect(ConfigurationManager.AppSettings["loginPage"] + "?msg=You have to login.");
}
return null;
}
return (AtuhenticatedUser)HttpContext.Current.Session["yk"];
}
}
Usually session is not available on application authenticate request.
Session will be available after OnAcquireRequestState call.
Here is application events call sequence
Also, note that session will be available, only if target HttpHandler implements IRequiresSessionState or IReadOnlySessionState, and AuhenticateRequest is usually called for resources like .js or .jpg.
Just throwing this out there. The proper way to reference it is:
System.Web.HttpContext.Current.Session
Or if you've referenced this assembly HttpContext.Current.Session should be good to go.
When i call the method with this code i'm getting error:
public partial class AddNews : System.Web.UI.Page
{
private AtuhenticatedUser yk = (new HelperClass()).f_IsAuthenticated(true);
protected void Page_Load(object sender, EventArgs e)
{
//
}
But when i call the method in Page_Load function it is working
public partial class AddNews : System.Web.UI.Page
{
private AtuhenticatedUser yk =new AtuhenticatedUser();
protected void Page_Load(object sender, EventArgs e)
{
yk = (new HelperClass()).f_IsAuthenticated(true);
}
I think Valera Kolupaev is right ;)
I want to intercept all method invocations to all seam components to see if that would help in logging exceptions. I was thinking that I could do this by getting the list of all components and registered interceptors and simply adding the one I want to that list.
Walter
Its better to use Seam's Exception handler.
This is how you can do it:
#Name("org.jboss.seam.exception.exceptions")
#Scope(ScopeType.APPLICATION)
#Install(precedence = Install.APPLICATION)
#BypassInterceptors
public class ExceptionHandler extends org.jboss.seam.exception.Exceptions {
public void handle(Exception e) throws Exception {
//Log your exception here if you want
Events.instance().raiseAsynchronousEvent("SomeListener",e.getMessage());
super.handle(e);
}
Try to override the default ExceptionFilter with your own at a higher precedence.
#Name("org.jboss.seam.web.exceptionFilter")
#Install(precedence = MOCK, classDependencies="javax.faces.context.FacesContext")
#BypassInterceptors
#Filter(within="org.jboss.seam.web.ajax4jsfFilter")
public class ExceptionFilter extends org.jboss.seam.web.ExceptionFilter
#Override
protected endWebRequestAfterException(javax.servlet.http.HttpServletRequest request, javax.servlet.http.HttpServletResponse response, Exception e) {
// here you log exceptions
}
}
I could really do with updating a user's session variables from within my HTTPModule, but from what I can see, it isn't possible.
UPDATE: My code is currently running inside the OnBeginRequest () event handler.
UPDATE: Following advice received so far, I tried adding this to the Init () routine in my HTTPModule:
AddHandler context.PreRequestHandlerExecute, AddressOf OnPreRequestHandlerExecute
But in my OnPreRequestHandlerExecute routine, the session state is still unavailable!
Thanks, and apologies if I'm missing something!
Found this over on the ASP.NET forums:
using System;
using System.Web;
using System.Web.Security;
using System.Web.SessionState;
using System.Diagnostics;
// This code demonstrates how to make session state available in HttpModule,
// regardless of requested resource.
// author: Tomasz Jastrzebski
public class MyHttpModule : IHttpModule
{
public void Init(HttpApplication application)
{
application.PostAcquireRequestState += new EventHandler(Application_PostAcquireRequestState);
application.PostMapRequestHandler += new EventHandler(Application_PostMapRequestHandler);
}
void Application_PostMapRequestHandler(object source, EventArgs e)
{
HttpApplication app = (HttpApplication)source;
if (app.Context.Handler is IReadOnlySessionState || app.Context.Handler is IRequiresSessionState) {
// no need to replace the current handler
return;
}
// swap the current handler
app.Context.Handler = new MyHttpHandler(app.Context.Handler);
}
void Application_PostAcquireRequestState(object source, EventArgs e)
{
HttpApplication app = (HttpApplication)source;
MyHttpHandler resourceHttpHandler = HttpContext.Current.Handler as MyHttpHandler;
if (resourceHttpHandler != null) {
// set the original handler back
HttpContext.Current.Handler = resourceHttpHandler.OriginalHandler;
}
// -> at this point session state should be available
Debug.Assert(app.Session != null, "it did not work :(");
}
public void Dispose()
{
}
// a temp handler used to force the SessionStateModule to load session state
public class MyHttpHandler : IHttpHandler, IRequiresSessionState
{
internal readonly IHttpHandler OriginalHandler;
public MyHttpHandler(IHttpHandler originalHandler)
{
OriginalHandler = originalHandler;
}
public void ProcessRequest(HttpContext context)
{
// do not worry, ProcessRequest() will not be called, but let's be safe
throw new InvalidOperationException("MyHttpHandler cannot process requests.");
}
public bool IsReusable
{
// IsReusable must be set to false since class has a member!
get { return false; }
}
}
}
HttpContext.Current.Session should Just Work, assuming your HTTP Module isn't handling any pipeline events that occur prior to the session state being initialized...
EDIT, after clarification in comments: when handling the BeginRequest event, the Session object will indeed still be null/Nothing, as it hasn't been initialized by the ASP.NET runtime yet. To work around this, move your handling code to an event that occurs after PostAcquireRequestState -- I like PreRequestHandlerExecute for that myself, as all low-level work is pretty much done at this stage, but you still pre-empt any normal processing.
Accessing the HttpContext.Current.Session in a IHttpModule can be done in the PreRequestHandlerExecute handler.
PreRequestHandlerExecute: "Occurs just before ASP.NET starts executing an event handler (for example, a page or an XML Web service)." This means that before an 'aspx' page is served this event gets executed. The 'session state' is available so you can knock yourself out.
Example:
public class SessionModule : IHttpModule
{
public void Init(HttpApplication context)
{
context.BeginRequest += BeginTransaction;
context.EndRequest += CommitAndCloseSession;
context.PreRequestHandlerExecute += PreRequestHandlerExecute;
}
public void Dispose() { }
public void PreRequestHandlerExecute(object sender, EventArgs e)
{
var context = ((HttpApplication)sender).Context;
context.Session["some_sesion"] = new SomeObject();
}
...
}
If you're writing a normal, basic HttpModule in a managed application that you want to apply to asp.net requests through pages or handlers, you just have to make sure you're using an event in the lifecycle after session creation. PreRequestHandlerExecute instead of Begin_Request is usually where I go. mdb has it right in his edit.
The longer code snippet originally listed as answering the question works, but is complicated and broader than the initial question. It will handle the case when the content is coming from something that doesn't have an ASP.net handler available where you can implement the IRequiresSessionState interface, thus triggering the session mechanism to make it available. (Like a static gif file on disk). It's basically setting a dummy handler that then just implements that interface to make the session available.
If you just want the session for your code, just pick the right event to handle in your module.
Since .NET 4.0 there is no need for this hack with IHttpHandler to load Session state (like one in most upvoted answer). There is a method HttpContext.SetSessionStateBehavior to define needed session behaviour.
If Session is needed on all requests set runAllManagedModulesForAllRequests to true in web.config HttpModule declaration, but be aware that there is a significant performance cost running all modules for all requests, so be sure to use preCondition="managedHandler" if you don't need Session for all requests.
For future readers here is a complete example:
web.config declaration - invoking HttpModule for all requests:
<system.webServer>
<modules runAllManagedModulesForAllRequests="true">
<add name="ModuleWithSessionAccess" type="HttpModuleWithSessionAccess.ModuleWithSessionAccess, HttpModuleWithSessionAccess"/>
</modules>
</system.webServer>
web.config declaration - invoking HttpModule only for managed requests:
<system.webServer>
<modules>
<add name="ModuleWithSessionAccess" type="HttpModuleWithSessionAccess.ModuleWithSessionAccess, HttpModuleWithSessionAccess" preCondition="managedHandler"/>
</modules>
</system.webServer>
IHttpModule implementation:
namespace HttpModuleWithSessionAccess
{
public class ModuleWithSessionAccess : IHttpModule
{
public void Init(HttpApplication context)
{
context.BeginRequest += Context_BeginRequest;
context.PreRequestHandlerExecute += Context_PreRequestHandlerExecute;
}
private void Context_BeginRequest(object sender, EventArgs e)
{
var app = (HttpApplication)sender;
app.Context.SetSessionStateBehavior(System.Web.SessionState.SessionStateBehavior.Required);
}
private void Context_PreRequestHandlerExecute(object sender, EventArgs e)
{
var app = (HttpApplication)sender;
if (app.Context.Session != null)
{
app.Context.Session["Random"] = $"Random value: {new Random().Next()}";
}
}
public void Dispose()
{
}
}
}
Try it: in class MyHttpModule declare:
private HttpApplication contextapp;
Then:
public void Init(HttpApplication application)
{
//Must be after AcquireRequestState - the session exist after RequestState
application.PostAcquireRequestState += new EventHandler(MyNewEvent);
this.contextapp=application;
}
And so, in another method (the event) in the same class:
public void MyNewEvent(object sender, EventArgs e)
{
//A example...
if(contextoapp.Context.Session != null)
{
this.contextapp.Context.Session.Timeout=30;
System.Diagnostics.Debug.WriteLine("Timeout changed");
}
}
I am trying to wire up dependency injection with Windsor to standard asp.net web forms. I think I have achieved this using a HttpModule and a CustomAttribute (code shown below), although the solution seems a little clunky and was wondering if there is a better supported solution out of the box with Windsor?
There are several files all shown together here
// index.aspx.cs
public partial class IndexPage : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
Logger.Write("page loading");
}
[Inject]
public ILogger Logger { get; set; }
}
// WindsorHttpModule.cs
public class WindsorHttpModule : IHttpModule
{
private HttpApplication _application;
private IoCProvider _iocProvider;
public void Init(HttpApplication context)
{
_application = context;
_iocProvider = context as IoCProvider;
if(_iocProvider == null)
{
throw new InvalidOperationException("Application must implement IoCProvider");
}
_application.PreRequestHandlerExecute += InitiateWindsor;
}
private void InitiateWindsor(object sender, System.EventArgs e)
{
Page currentPage = _application.Context.CurrentHandler as Page;
if(currentPage != null)
{
InjectPropertiesOn(currentPage);
currentPage.InitComplete += delegate { InjectUserControls(currentPage); };
}
}
private void InjectUserControls(Control parent)
{
if(parent.Controls != null)
{
foreach (Control control in parent.Controls)
{
if(control is UserControl)
{
InjectPropertiesOn(control);
}
InjectUserControls(control);
}
}
}
private void InjectPropertiesOn(object currentPage)
{
PropertyInfo[] properties = currentPage.GetType().GetProperties();
foreach(PropertyInfo property in properties)
{
object[] attributes = property.GetCustomAttributes(typeof (InjectAttribute), false);
if(attributes != null && attributes.Length > 0)
{
object valueToInject = _iocProvider.Container.Resolve(property.PropertyType);
property.SetValue(currentPage, valueToInject, null);
}
}
}
}
// Global.asax.cs
public class Global : System.Web.HttpApplication, IoCProvider
{
private IWindsorContainer _container;
public override void Init()
{
base.Init();
InitializeIoC();
}
private void InitializeIoC()
{
_container = new WindsorContainer();
_container.AddComponent<ILogger, Logger>();
}
public IWindsorContainer Container
{
get { return _container; }
}
}
public interface IoCProvider
{
IWindsorContainer Container { get; }
}
I think you're basically on the right track - If you have not already I would suggest taking a look at Rhino Igloo, an WebForms MVC framework, Here's a good blog post on this and the source is here - Ayende (the Author of Rhino Igloo) tackles the issue of using Windsor with webforms quite well in this project/library.
I would cache the reflection info if you're going to inject the entire nested set of controls, that could end up being a bit of a performance hog I suspect.
Last of all spring.net approaches this in a more configuration-oriented way, but it might be worth taking a look at their implementation - here's a good reference blog post on this.
Here's a modified version of the OP's code that (i) caches injected properties to avoid repeated reflection calls, (ii) releases all resolved components, (iii) encapsulates container access so as not to expose implementation.
// global.asax.cs
public class Global : HttpApplication
{
private static IWindsorContainer _container;
protected void Application_Start(object sender, EventArgs e)
{
_container = new WindsorContainer();
_container.Install(FromAssembly.This());
}
internal static object Resolve(Type type)
{
return _container.Resolve(type);
}
internal static void Release(object component)
{
_container.Release(component);
}
//...
}
// WindsorHttpModule.cs
public class WindsorHttpModule : IHttpModule
{
// cache the properties to inject for each page
private static readonly ConcurrentDictionary<Type, PropertyInfo[]> InjectedProperties = new ConcurrentDictionary<Type, PropertyInfo[]>();
private HttpApplication _context;
public void Init(HttpApplication context)
{
_context = context;
_context.PreRequestHandlerExecute += InjectProperties;
_context.EndRequest += ReleaseComponents;
}
private void InjectProperties(object sender, EventArgs e)
{
var currentPage = _context.Context.CurrentHandler as Page;
if (currentPage != null)
{
InjectProperties(currentPage);
currentPage.InitComplete += delegate { InjectUserControls(currentPage); };
}
}
private void InjectUserControls(Control parent)
{
foreach (Control control in parent.Controls)
{
if (control is UserControl)
{
InjectProperties(control);
}
InjectUserControls(control);
}
}
private void InjectProperties(Control control)
{
ResolvedComponents = new List<object>();
var pageType = control.GetType();
PropertyInfo[] properties;
if (!InjectedProperties.TryGetValue(pageType, out properties))
{
properties = control.GetType().GetProperties()
.Where(p => p.GetCustomAttributes(typeof(InjectAttribute), false).Length > 0)
.ToArray();
InjectedProperties.TryAdd(pageType, properties);
}
foreach (var property in properties)
{
var component = Global.Resolve(property.PropertyType);
property.SetValue(control, component, null);
ResolvedComponents.Add(component);
}
}
private void ReleaseComponents(object sender, EventArgs e)
{
var resolvedComponents = ResolvedComponents;
if (resolvedComponents != null)
{
foreach (var component in ResolvedComponents)
{
Global.Release(component);
}
}
}
private List<object> ResolvedComponents
{
get { return (List<object>)HttpContext.Current.Items["ResolvedComponents"]; }
set { HttpContext.Current.Items["ResolvedComponents"] = value; }
}
public void Dispose()
{ }
}
I've recently started at a company where there are a lot of legacy webform apps, so this looks to be a real interesting approach, and could offer a way forward if we wanted to add DI to existing web pages, thanks.
One point I noticed is that the Injection method uses the container.Resolve to explicitly resolve components, therefore I think we may need to do a container.Release on the components when the Page Unloads.
If we have transient components and don't do this then we may face memory leakages. Not sure how components with Per Web Request lifestyles would behave (i.e. would Windsor pick them up at the end of the web request, even though we explicitly resolved them) but here too may want to play safe.
Therefore the module may need to be extended to keep track of the components that it resolves and release them so that Windsor knows when to clean up.
One thing that was missing from the accepted answers was the fact that the http module needs to be registered in the web.config file (depending on the application) before the module will actually resolve the dependencies on the code-behind pages. What you need is :
<system.webServer>
<modules>
<add name="ClassNameForHttpModuleHere" type="NamespaceForClass"/>
</modules>
</system.webServer>
Other than that the accepted solutions worked like a charm.
Reference to the Microsoft website for adding http modules: https://msdn.microsoft.com/en-us/library/ms227673.aspx
Rather than doing it like this, you could also use a type resolver directly with something like:
ILogger Logger = ResolveType.Of<ILogger>();