FIX: Fast Cache on Windows Media Services 9 Series may not work with a custom plug-in

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Article ID: 840411 - View products that this article applies to.
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SYMPTOMS

When you write a custom Event Notification plug-in to change the WMS_PRESENT_PHYSICAL_NAME context value for Microsoft Windows Media Server in an event handler, you may experience either one of the following behaviors:
  • If the content that was originally requested by the client exists in the source path of the publishing point, the server will Fast Cache the content to the client. This behavior occurs regardless of the new WMS_PRESENT_PHYSICAL_NAME context value that was modified by the event plug-in.
  • If the content that was originally requested by the client does not exist in the source path of the publishing point, the server will not Fast Cache the content to the client. This behavior occurs regardless of the new WMS_PRESENT_PHYSICAL_NAME context value that was modified by the event plug-in.

CAUSE

When the server creates the data container for streaming back to the client, the server sets the cache flags on the data container. The settings are based on the path that was specified in the original client request. Although an administrator may have written a custom event plug-in to change the content source, the server still uses the original request to create the data container.

RESOLUTION

A supported hotfix is now available from Microsoft, but it is only intended to correct the problem that is described in this article. Only apply it to systems that are experiencing this specific problem. This hotfix may receive additional testing. Therefore, if you are not severely affected by this problem, we recommend that you wait for the next service pack that contains this hotfix.

To resolve this problem immediately, contact Microsoft Product Support Services to obtain the hotfix. For a complete list of Microsoft Product Support Services telephone numbers and information about support costs, visit the following Microsoft Web site:
http://support.microsoft.com/contactus/?ws=support
Note In special cases, charges that are ordinarily incurred for support calls may be canceled if a Microsoft Support Professional determines that a specific update will resolve your problem. The usual support costs will apply to additional support questions and issues that do not qualify for the specific update in question.

The following file is available for download from the Microsoft Download Center:
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Download the WindowsMedia9-KB840411-ENU.exe package now.

For additional information about how to download Microsoft Support files, click the following article number to view the article in the Microsoft Knowledge Base:
119591 How to Obtain Microsoft Support Files from Online Services
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The English version of this hotfix has the file attributes (or later) that are listed in the following table. The dates and times for these files are listed in coordinated universal time (UTC). When you view the file information, it is converted to local time. To find the difference between UTC and local time, use the Time Zone tab in the Date and Time tool in Control Panel.
   Date         Time   Version            Size    File name
   --------------------------------------------------------------
   07-Apr-2004  04:29  9.0.0.3377      2,392,576  Wmsserver.dll    

STATUS

Microsoft has confirmed that this is a bug in the Microsoft products that are listed in the "Applies to" section.

MORE INFORMATION

Steps to reproduce the problem


To reproduce the problem, use the following Active Script (.vbs):
Function OnWMSEAuthorizePhysicalURLTransform (UserCtx, PresCtx, CmdCtx)
On Error Resume Next
     PresCtx("WMS_PRESENT_PHYSICAL_NAME") = "file://\\server\share$\sample.asf"
     OnWMSEAuthorizePhysicalURLTransform = &H00000000
End Function
  1. Create an On-Demand Publishing Point for the server that points to the path that contains the Exist.wmv file.
  2. Copy the previous script to a .vbs file, and then set the WMS Active Script plug-in to use this script as the source script.

    Modify the path if you have to.
  3. In Microsoft Windows Media Player, make the following request:

    mms://server/DOES_NOT_EXIST.wmv
  4. The event plug-in sets the WMS_PRESENT_PHYSICAL_NAME context value to the following:

    \\server\share$\sample.asf
  5. Receive sample.asf, Fast Cache DOES NOT WORK as seen by the RTSPU:// protocol in the Advanced Statistics dialog of the Player.
  6. In the Windows Media Player, make the following request:

    mms://server/EXIST.wmv
  7. The event plug-in sets the WMS_PRESENT_PHYSICAL_NAME context value to the following:

    \\server\share$\sample.asf
  8. When receiving sample.asf, Fast Cache WORKS as seen by streaming via the RTSPT:// protocol and then a change to CACHE as the protocol in the Advanced Statistics dialog of the Player

Properties

Article ID: 840411 - Last Review: September 27, 2011 - Revision: 2.0
APPLIES TO
  • Microsoft Windows Media Services 9 Series
Keywords: 
kbdownload kbfix kbqfe kbhotfixserver KB840411

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