I have a problem when accessing httpcontext.current value at application_start method.
There is a lots of discussions about this topic.
But I want to share my business logic and I need some advice how to handle problem.
Let's look at this business logic together step by step
1-I want to design "custom object" which has "static global List" property and any user can add "LogObj" object to this list whereever actions occured.
public class MyLog
{
public static void List<LogObj> LogObjList {get;set;}
static MyLog()
{
LogObjList = new List<LogObj>();
}
}
2- If I have a "System.Timers.Timer" object which checks the "static global List" every X milliseconds and performs some action which defined in the code
public static init(){
System.Timers.Timer t = new System.Timers.Timer();
t.Elapsed += T_Elapsed;
t.Interval = 3000;
t.Start();
}
private void T_Elapsed(object sender, System.Timers.ElapsedEventArgs e)
{
//perform some code.
var s = HttpContext.Current.Session["test"];
var logObj = MyLog.LogObjList[0] + s;
//save as text file ...
}
3- If I start init() method in application_start event at global.asax I get this error "object reference ..." where the line of "..HttpContext.Current.Session" started.
So
If I do not want to access any httpcontext.current's properties I have no problem at this situation.
But If I need to access any properties of httpcontext.current at Timer_Elapsed event I have problem about it.
So I need your advice or alternative way to making my algorithm.
Thank you
Related
I'm using EF 5 with Web Forms (ASP.NET 4.5), with the "one DbContext instance per request" approach.
But this situation is a bit complicated: I have a multi-step create/edit screen, and I store the current entity in Session, then I manipulate it and in the final step, I commit it to the Database.
Creating a new instance was fine, but I can't for the life of me edit an existing entity... Because it's another request, my original DbContext instance was lost and when I attach it to a new one, I get the An entity object cannot be referenced by multiple instances of IEntityChangeTracker error.
My code is far too complex to post here, but I'll try and summarize it accurately:
My DbContext:
public class AppContext : DbContext
{
// DbSet declarations...
public static AppContext Current {
get { var context = HttpContext.Current.Items["Contexts.AppContext"] as AppContext;
if (context == null)
{
context = new AppContext();
HttpContext.Current.Items["Contexts.AppContext"] = context;
}
return context;
}
}
}
An example of what the page code looks like:
protected void Page_Load(object sender, EventArgs e)
{
int? id = null; // After this, I try to get it from the QueryString, parse it, etc.. Omitted for sake of brevity
// If I have an ID, it means I'm editing...
Session["Product"] = id.HasValue ? new Product() : AppContext.Current.Products.Find(id));
MethodToPopulateFields(); // Internally, it uses the Session variable
}
protected void Step1(){ // through n
// Manipulates the Session["Product"] based on page input...
}
protected void Save(){
var product = Session["Product"] as Product;
if(product.ID == 0)
product = AppContext.Current.Products.Add(product);
// throws an exception:
// AppContext.Current.Entry(product).State = EntityState.Modified;
// this too:
// AppContext.Products.Attach(product);
AppContext.Current.SaveChanges();
}
I know I can get the old entity from the database, update it manually and save, all in the last step, but I really don't want to do that...
Thank you.
Try calling
AppContext.Current.Entry(product).State = EntityState.Detached;
in the first method.
Last few days I thinkin about output cache in asp.net. In my task I need to implement output cache for the very big project. After hours of searching I did not find any examples.
Most popular way to use output cache is declarative, in this case you need to write something like this on the page which you want to cache.
But if you need to cache whole site you must write this on all pages or master pages on project. It is madness. In this case you cant store all configuration in one place. All page have his own configurations..
Global.asax could help me, but my site contains about 20 web progects and ~20 global.asax files. And i don't want copy same code to each project.
For these reasons, i made decision to create HTTPModule.
In Init method i subscribe to two events :
public void Init(HttpApplication app)
{
app.PreRequestHandlerExecute += new EventHandler(OnApplicationPreRequestHandlerExecute);
app.PostRequestHandlerExecute += new EventHandler(OnPostRequestHandlerExecute);
}
In method "OnPostRequestHandlerExecute" I set up output caching parameters for each new request :
public void OnPostRequestHandlerExecute(object sender, EventArgs e)
{
HttpApplication app = (HttpApplication)sender;
HttpCachePolicy policy = app.Response.Cache;
policy.SetCacheability(HttpCacheability.Server);
policy.SetExpires(app.Context.Timestamp.AddSeconds((double)600));
policy.SetMaxAge(new TimeSpan(0, 0, 600));
policy.SetValidUntilExpires(true);
policy.SetLastModified(app.Context.Timestamp);
policy.VaryByParams.IgnoreParams = true;
}
In "OnApplicationPreRequestHandlerExecute" method I set calback method to cache validation:
public void OnApplicationPreRequestHandlerExecute(object sender, EventArgs e)
{
HttpApplication app = (HttpApplication)sender;
app.Context.Response.Cache.AddValidationCallback(new HttpCacheValidateHandler(Validate), app);
}
And last part - callback validation method :
public void Validate(HttpContext context, Object data, ref HttpValidationStatus status)
{
if (context.Request.QueryString["id"] == "5")
{
status = HttpValidationStatus.IgnoreThisRequest;
context.Response.Cache.AddValidationCallback(new HttpCacheValidateHandler(Validate), "somecustomdata");
}
else
{
status = HttpValidationStatus.Valid;
}
}
To attach my HttpModule I use programmatically attach method :
[assembly: PreApplicationStartMethod(typeof(OutputCacheModule), "RegisterModule")]
This method works perfectly, but I want to know is there other ways to do this.
Thanks.
Try seeing if IIS caching provides what you need.
http://www.iis.net/configreference/system.webserver/caching
I'm adding ASP.NET routing to an older webforms app. I'm using a custom HttpHandler to process everything. In some situations I would like to map a particular path back to an aspx file, so I need to just pass control back to the default HttpHandler for asp.net.
The closest I've gotten is this
public void ProcessRequest(HttpContext context) {
// .. when we decide to pass it on
var handler = new System.Web.UI.Page();
handler.ProcessRequest(context);
MemoryStream steam = new MemoryStream();
StreamWriter writer = new StreamWriter(stream);
HtmlTextWriter htmlWriter = new HtmlTextWriter(writer);
handler.RenderControl(htmlWriter);
// write headers, etc. & send stream to Response
}
It doesn't do anything, there's nothing output to the stream. MS's documentation for System.Web.UI.Page (as an IHttpHandler) say something to the effect of "do not call the ProcessRequest method. It's for internal use."
From looking around it seems like you can do this with MVC, e.g. : MvcHttpHandler doesn't seem to implement IHttpHandler
There is also this thing System.Web.UI.PageHandlerFactory which appears that it would just produce a Page handler for an aspx file, but it's internal and I can't use it directly.
This page: http://msdn.microsoft.com/en-us/library/bb398986.aspx refers to the "default asp.net handler" but does not identify a class or give any indication how one might use it.
Any ideas on how I can do this? Is it possible?
Persistence pays off! This actually works, and since this information seems to be available pretty much nowhere I thought I'd answer my own question. Thanks to Robert for this post on instantiating things with internal constructors, this is the key.
http://www.rvenables.com/2009/08/instantiating-classes-with-internal-constructors/
public void ProcessRequest(HttpContext context) {
// the internal constructor doesn't do anything but prevent you from instantiating
// the factory, so we can skip it.
PageHandlerFactory factory =
(PageHandlerFactory)System.Runtime.Serialization.FormatterServices
.GetUninitializedObject(typeof(System.Web.UI.PageHandlerFactory));
string newTarget = "default.aspx";
string newQueryString = // whatever you want
string oldQueryString = context.Request.QueryString.ToString();
string queryString = newQueryString + oldQueryString!="" ?
"&" + newQueryString :
"";
// the 3rd parameter must be just the file name.
// the 4th parameter should be the physical path to the file, though it also
// works fine if you pass an empty string - perhaps that's only to override
// the usual presentation based on the path?
var handler = factory.GetHandler(context, "GET",newTarget,
context.Request.MapPath(context,newTarget));
// Update the context object as it should appear to your page/app, and
// assign your new handler.
context.RewritePath(newTarget , "", queryString);
context.Handler = handler;
// .. and done
handler.ProcessRequest(context);
}
... and like some small miracle, an aspx page processes & renders completely in-process without the need to redirect.
I expect this will only work in IIS7.
I'm you're using Routing in webforms you should be able to just add an ignore route for the specific .aspx files you want. This will then be handled by the default HttpHandler.
http://msdn.microsoft.com/en-us/library/dd505203.aspx
Another option is to invert the logic by handling the cases in which you do NOT want to return the default response and remap the others to your own IHttpHandler. Whenever myCondition is false, the response will be the "default". The switch is implemented as an IHttpModule:
public class SwitchModule: IHttpModule
{
public void Init(HttpApplication context)
{
context.PostAuthenticateRequest += app_PostAuthenticateRequest;
}
void app_PostAuthenticateRequest(object sender, EventArgs e)
{
// Check for whatever condition you like
if (true)
HttpContext.Current.RemapHandler(new CustomHandler());
}
public void Dispose()
}
internal class CustomHandler: IHttpHandler
{
public void ProcessRequest(HttpContext context)
{
context.Response.Write("hallo");
}
public bool IsReusable { get; }
}
I've a static page method in web form application and I want to call method on private class level variable from it as shown below. I'm using jQuery to call the page method.
private readonly ICatalogBLL _catalogBLL = new CatalogBLL();
protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
{
_catalogBLL.GetSomething();
}
}
[WebMethod]
public static UpdateSomething(int i)
{
//Want to do as below. But can't call it from a static method.
_catalogBLL.UpdateSomething();
}
UPDATE
If I call it as said by John Saunders, won't it use the same instance for requests from different users as it is within a static method?
You can't. The page method is static. Your _catalogBLL is an instance member.
However, since you create a new instance of CatalogBLL on every request, why not do so once more?
[WebMethod]
public static UpdateSomething(int i)
{
CatalogBLL catalogBLL = new CatalogBLL();
catalogBLL.UpdateSomething();
}
You can't call because pagemethods are static...
A static method is simply one that is disassociated from any instance of its containing class. The more common alternative is an instance method, which is a method whose result is dependent on the state of a particular instance of the class it belongs to.
Look at John saunder's answer..
Being new to RhinoMocks and Unit Testing, I have come accross an issue that I cannot seem to find a resolution to (no matter how much documentation I read).
The issue is this: I have created an Interface that exposes 5 Events (to be used for a view in ASP.NET and the MVP Supervisory Controller pattern..... I know, I should be using MVC, but that's a whole other issue). Anyway, I want to test that when a certain event fires on the view, we'll call it "IsLoaded", that a method inside of my Presenter is called and, using Dependency Injection, a value is returned from the Dependency and set to the view. Here is where the problem starts: when I use Expect.Call(Dependency.GetInfo()).Return(SomeList), the Call never executes (without the mock.ReplayAll() method being invoked). Well, when I invoke the ReplayAll method, I get ExpectationExceptions because of the Subscription by the Presenter object to the other Events exposed by the View Interface.
So, for me to test that IView.IsLoaded has fired, I want to verify that IView.ListOfSomething has been updated to match the list I passed in via the Expect.Call(). However, when I set the expectation, the other Event subscriptions (which occur straight out of the constructor for the Presenter) fail the #0 Expectations of the test. What I get is, view.Save += this.SaveNewList tosses up a RhinoMocks ExpectationViolationException.
My million dollar question is this: Is it necessary I set expectations for ALL of my events (via [Setup]), or is there something that I'm missing/not understanding about how Unit Testing or RhinoMocks works?
Please bear in mind I am extremely new to Unit Testing, and therefore RhinoMocks. If it appears I don't know what I'm talking about, please feel free to point that out.
I'm working on a project where we used MVP and rhino mocks as well. What we did was simply expect all event subscriptions in every test.
private void SetupDefaultExpectations()
{
_mockView.Initializing += null; LastCall.IgnoreArguments();
_mockView.SavingChanges += null; LastCall.IgnoreArguments();
}
Then we built a extension method on IMockedObject (from RhinoMocks) to trigger events in the unit tests and un-wrap exceptions so that they can be expected in the standard NUnit way.
static class IMockedObjectExtension
{
public static void RaiseEvent(this IMockedObject mockView, string eventName, EventArgs args)
{
EventRaiser eventraiser = new EventRaiser(mockView, eventName);
try
{
eventraiser.Raise(mockView, args);
}
catch (TargetInvocationException ex)
{
throw ex.InnerException;
}
}
public static void RaiseEvent(this IMockedObject mockView, string eventName)
{
RaiseEvent(mockView, eventName, EventArgs.Empty);
}
}
This could then be used from the unit test like this
using(_mocks.Record())
{
Expect.Call(dependency.GetInfo()).Return(someList);
}
using(_mocks.Playback())
{
Presenter presenter = new Presenter(_mockView, dependency);
(_mockView as IMockedObject).RaiseEvent("SavingChanges");
}
To eliminate duplication between presenter tests we have refactored this to a BasePresenterTest base class which sets up this basic structure for all presenter tests and exposes helper methods to the sub class.
public abstract class BasePresenterTest<VIEW> where VIEW : IBaseView
{
protected MockRepository _mocks;
protected VIEW View { get; private set; }
protected abstract void SetUp();
protected abstract void TearDown();
protected abstract void SetupDefaultExpectations();
[SetUp]
public virtual void BaseSetUp()
{
_mocks = new MockRepository();
View = _mocks.CreateMock<VIEW>();
SetUp();
}
[TearDown]
public virtual void BaseTearDown()
{
TearDown();
View = null;
_mocks = null;
}
protected virtual void BaseSetupDefaultExpectations()
{
//Setup default expectations that are general for all views
SetupDefaultExpectations();
}
protected virtual IDisposable Record()
{
IDisposable mocksRecordState = _mocks.Record();
BaseSetupDefaultExpectations();
return mocksRecordState;
}
protected virtual IDisposable Playback()
{
return _mocks.Playback();
}
protected void RaiseEventOnView(string eventName)
{
(View as IMockedObject).RaiseEvent(eventName);
}
}
This eliminates alot of code from the tests in our project.
We still use a old version of RhinoMocks but I will try to update this once we move to a later version.