Http handler not working RSS

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  dutta_sudipt...

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  67 Points

  29 Posts

  Http handler not working

  Jun 30, 2012 02:11 AM|LINK

  I was trying to learn the functionality of HTTP handlers. I developed a simple image request handler in VS 2008 and it is working. But when I tried same thing in VS 2010 I am facing problem.

  What I did:

  I wrote a Http handler class named JpegImageHandler derived from IHttpHandler interface and implemented IsReusable property and ProcessRequest method. I put it in App_Code folder. Code is - 

  Imports Microsoft.VisualBasic
  
  Public Class JpegImageHandler
      Implements IHttpHandler
  
  
      Public ReadOnly Property IsReusable As Boolean Implements System.Web.IHttpHandler.IsReusable
          Get
              Return False
          End Get
      End Property
  
      Public Sub ProcessRequest(context As System.Web.HttpContext) Implements System.Web.IHttpHandler.ProcessRequest
          context.Response.ContentType = "image/jpg"
          Dim req As HttpRequest = context.Request
          Dim res As HttpResponse = context.Response
  
          If req.RawUrl.ToLower().Contains("Flower1") Then
              res.TransmitFile(req.PhysicalApplicationPath & "/Chrysanthemum.jpg")
          End If
          If req.RawUrl.ToLower().Contains("DryLand1") Then
              res.TransmitFile(req.PhysicalApplicationPath & "/Desert.jpg")
          End If
          If req.RawUrl.ToLower().Contains("WaterAnimal1") Then
              res.TransmitFile(req.PhysicalApplicationPath & "/Hydrangeas.jpg")
          End If
      End Sub
  End Class

  Then I registered the handler in web.config file by - 

  <system.webServer>
  <validation validateIntegratedModeConfiguration="false" />
  <modules runAllManagedModulesForAllRequests="true" />
  <handlers>
  <add name="JpegImage" path="*.jpg" verb="*" type="JpegImageHandler" resourceType="Unspecified" preCondition="integratedMode" />
  </handlers>
  </system.webServer>

  
  (I know it works for IIS 7.0 Integrated mode. I also tried the IIS 6.0 version <system.web> & <httpHandler> but failed.)

  Then I designed a simple web page with 3 image buttons and handled click events as 

  Protected Sub imbChrysanthemum_Click(sender As Object, e As System.Web.UI.ImageClickEventArgs) Handles imbChrysanthemum.Click
          Response.Redirect("Flower1.jpg")
      End Sub
  
      Protected Sub imbDesert_Click(sender As Object, e As System.Web.UI.ImageClickEventArgs) Handles imbDesert.Click
          Response.Redirect("DryLand1.jpg")
      End Sub
  
      Protected Sub imbHydrangeas_Click(sender As Object, e As System.Web.UI.ImageClickEventArgs) Handles imbHydrangeas.Click
          Response.Redirect("WaterAnimal1.jpg")
      End Sub

  Look I don't have Flower1.jpg, DryLand1.jpg or WaterAnimal1.jpg, but I have Chrysanthemum.jpg, Desert.jpg and Hydrangeas.jpg. I want to process the requests to those files and redirect to original ones.

  Now whenever I am browsing the page and clicking the image buttons it is trying to redirect to Flower1.jpg, Dryland1.jpg or WaterAnimal1.jpg and obviously giving 404 error.

  I tried the same thing modifying web.config with IIS 6.0 version and even I checked that the images are there(!).

  Please HELP.

  
  
  

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  hirendaraji

  Member

  186 Points

  39 Posts

  Re: Http handler not working

  Jun 30, 2012 03:13 AM|LINK

  First thing is that you have to got  404 error means , your http handler called but there is problem with image physical path.

  so check your image path return from hander is same as image physical located path.

  • Marked as answer by dutta_sudipta on Jun 30, 2012 06:44 PM
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  dutta_sudipt...

  Member

  67 Points

  29 Posts

  Re: Http handler not working

  Jun 30, 2012 07:09 AM|LINK

  Thanks Hiren, for raising the helping hand. Actually I don't have Flower1.jpg, Dryland1.jpg or WaterAnimal1.jpg. But I have Chrysanthemum.jpg, Desert.jpg and Hydrangeas.jpg in my Project directory (first I tried to keep them in a different "Image" directory, which also failed). Now when the http handler class will take the responsibility, the ProcessRequest( ) should be called and the reference to those three files should be redirected to the original files. Now 404 may occur in two situations - if request to Flower1.jpg is made and it searches for "Flower1.jpg" (bypassing the http handler) or somehow not getting Chrysanthemum.jpg.

  The worst(!) thing is the same type of code is working with Visual Studio 2008!

  • Edited by dutta_sudipta on Jun 30, 2012 06:44 PM
  • Edited by dutta_sudipta on Jun 30, 2012 06:44 PM
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  BrockAllen

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  Re: Http handler not working

  Jun 30, 2012 01:21 PM|LINK

  Anytime I can't seem to get IIS to run my module or handler, I enable FREB and check the log as to where in the pipeline it's failing the call.

  Brock Allen | http://brockallen.com
  DevelopMentor | http://www.develop.com
  thinktecture | http://www.thinktecture.com/
  • Marked as answer by dutta_sudipta on Jun 30, 2012 06:44 PM
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  dutta_sudipt...

  Member

  67 Points

  29 Posts

  Re: Http handler not working

  Jun 30, 2012 06:43 PM|LINK

  So weird! I deleted my previous project and restarted a fresh new one with same task. Now everything working! Now it is doing everything whatever I want. This time I tried with IIS 6.0 Version of web.config file. It is working (previously it was not working! Trust me!). The problem solved, but I don't know whose answer should be chosen as the correct one! Thank you friends for your support.