What's New in ASP

Article
10/08/2009

Applies To: Windows Server 2003, Windows Server 2003 R2, Windows Server 2003 with SP1

In addition to internal performance enhancements and optimizations, this version of Active Server Pages (ASP) has the following new features:

Better International and UTF-8 Support
Improved POST Support
ASP Hang Detection
Caching of Popular Files
UNC Enhancements
COM+ Services in ASP
- Apartment Model Selection
- Side-by-side Assemblies
- COM+ Partitions
- Tracker
- Transactions
New Metabase Properties for ASP
ASP Debugging

Better International and UTF-8 Support

UTF-8 support has been expanded to all ASP built-in object properties and methods. The last version of ASP supported UTF-8 only for Response.Write.

Improved POST Support

ASP can now read chunked-encoded POST data from a client.

ASP Hang Detection

When an IIS Web site is busy there may be instances when the maximum number of ASP threads has been spawned and some of the ASP threads are hung, resulting in degraded performance. HSE_REQ_REPORT_UNHEALTHY, and the World Wide Web Publishing Service (WWW service) will recycle the worker process hosting ASP.dll and make an entry in the event log.

Note

Threads are considered hung if they do not respond to a timeout.

Caching of Popular Files

ASP now caches some of the most-recently used files on disk, in addition to keeping a memory cache. The default location of the disk cache is %systemroot%\System32\inetsrv\ASP Compiled Templates. You can change the location of the disk cache by setting the AspDiskTemplateCacheDirectory Metabase Property.

UNC Enhancements

ASP can now handle UNC paths in ASP scripts.

COM+ Services in ASP

If you wanted to use COM+ services from an ASP application in previous versions of IIS, you had to create a COM component that would call the methods of those services. Now, you can configure your ASP application to use the following COM+ services without having to create a COM component:

Apartment Model Selection:

ASP is now capable of running all of its threads in a multi-threaded apartment (MTA). If your COM components are primarily free-threaded or both-threaded, running the ASP threads as MTA can improve performance significantly.

To enable an ASP application to run in an MTA, you can use the metabase setting, AspExecuteInMTA Metabase Property, at the application level. This means that you can have one application running on ASP MTA threads and a second application running on ASP STA (single-threaded apartment) threads. The default for ASP threads continues to be STA.

Important

When you switch an ASP application from running in STA to MTA (or from MTA to STA), the impersonation token becomes obsolete. This can cause the application to run with no impersonation, effectively letting it run with the identity of the process which might allow access to other resources. If you must switch threading models, disable the application and unload it before you make the change.

The following example sets the Default Web Site application (W3SVC/1/ROOT) to execute in MTA:
```
    On Error Resume Next
    set providerObj = GetObject("winmgmts://MyMachine/root/MicrosoftIISv2")
    ' Get a reference to the ASP application called Default Web Site
    set IIsWebVirtualDirSettingObj = providerObj.get("IIsWebVirtualDirSetting='W3SVC/1/ROOT'")
    WScript.Echo "Before: AspExecuteInMTA = " & IIsWebVirtualDirSettingObj.AspExecuteInMTA
    ' Set the ASP application to execute in MTA
    IIsWebVirtualDirSettingObj.AspExecuteInMTA = 1
    IIsWebVirtualDirSettingObj.Put_()
    WScript.Echo "After: AspExecuteInMTA = " & IIsWebVirtualDirSettingObj.AspExecuteInMTA
```
Side-by-side Assemblies:

Side-by-side (SxS) assemblies allow ASP applications to specify which version of a system DLL or classic COM component to use, such as WinHTTP 5.1, Shell Common Controls version 6.0 (Comctl32.dll), GDI Plus version 1.0 (GDIplus.dll), and Visual C++ Run-time Libraries version 6.0. For example, if your ASP application relies on MSXML version 2.0, you can ensure that your application still uses MSXML version 2.0 even after service packs are applied to the server. Any new version of MSXML is still installed on the computer, but version 2.0 remains and is used by your application. Configuring SxS assemblies requires that you know the path to the DLL, and that the COM+ manifest file exists in every virtual directory that needs to use the DLL. The COM+ manifest is an XML file that has information about where a DLL is installed. IIS does not verify that the manifest exists. A manifest looks like the following file excerpt:
```
    <?xml version="1.0" encoding="UTF-8" standalone="yes"?>
    <assembly xmlns="urn:schemas-microsoft-com:asm.v1" manifestVersion="1.0">
    <assemblyIdentity publicKeyToken="75e377300ab7b886" type="win32" name="Test4Dir" version="1.0.0.0" processorArchitecture="x86"/>
    <file name="DirComp.dll" hash="35ca6f27b11ed948ac6e50b75566355f0991d5d9" hashalg="SHA1">
    <comClass clsid="{6C6CC20E-0F85-49C0-A14D-D09102BD7CDC}" progid="DirComp.PathInfo" threadingModel="apartment"/>
    <typelib tlbid="{AA56D6B8-9ADB-415D-9E10-16DD68447319}" version="1.0" helpdir=""/>
    </file>
    </assembly>
```
You can enable side-by-side assemblies on the IIS side programmatically or by using IIS Manager.

To enable side-by-side assemblies on the IIS side using IIS Manager

In IIS Manager, right-click a Web site or virtual directory and click Properties.
Click the Virtual Directory tab, and click Configuration.
If the configuration button is not available, it is because you have not created an application for this virtual directory. Click Create to create an application.
In the Application Configuration dialog box, click the Options tab.
Select the Enable Side by Side assemblies check box.
In the Manifest file name box, type the name of the COM+ manifest file.
Click OK twice.

To enable side-by-side assemblies programmatically, set the AspEnableSxs flag of the AspAppServiceFlags Metabase Property. Also set the AspSxsName Metabase Property to the name of the COM+ manifest name. Set both metabase properties at the application level.

Important

Only one version of a system DLL can be used in any application pool, even though this feature is configurable at the application level. For example, if application App1 uses MDAC, version 2.5 and application App2 uses MDAC, version 2.4, then App1 and App2 should not be in the same application pool. If they are, the application that is loaded first has its version of MDAC loaded, and the other application is forced to use it until the applications are unloaded.

The following example enables side-by-side assemblies on the Default Web Site application (W3SVC/1/ROOT). Notice that after setting only the AspEnableTracker property, the AspAppServiceFlags property changes as well:

On Error Resume Next
    set providerObj = GetObject("winmgmts://MyMachine/root/MicrosoftIISv2")
    ' Get a reference to the ASP application called Default Web Site
    set IIsWebVirtualDirSettingObj = providerObj.get("IIsWebVirtualDirSetting='W3SVC/1/ROOT'")
    WScript.Echo "Before: AspEnableSxs = " & IIsWebVirtualDirSettingObj.AspEnableSxs
    WScript.Echo "        AspSxsName = " & IIsWebVirtualDirSettingObj.AspSxsName
    WScript.Echo "        AspAppServiceFlags = " & IIsWebVirtualDirSettingObj.AspAppServiceFlags
    ' Set the ASP application to enable COM+ side-by-side assemblies
    IIsWebVirtualDirSettingObj.AspEnableSxs = 1
    ' Set the AspSxsName property
    IIsWebVirtualDirSettingObj.AspSxsName = "VersionInfo"
    ' Save the values to the IIS metabase
    IIsWebVirtualDirSettingObj.Put_()
    ' Get the reference again in order to refresh the AspAppServiceFlags property.
    set IIsWebVirtualDirSettingObj = Nothing
    set IIsWebVirtualDirSettingObj = providerObj.get("IIsWebVirtualDirSetting='W3SVC/1/ROOT'")
    WScript.Echo "After: AspEnableSxs = " & IIsWebVirtualDirSettingObj.AspEnableSxs
    WScript.Echo "       AspSxsName = " & IIsWebVirtualDirSettingObj.AspSxsName
    WScript.Echo "       AspAppServiceFlags = " & IIsWebVirtualDirSettingObj.AspAppServiceFlags

COM+ Partitions:

COM+ Partitions can be used to isolate Web applications into their own COM+ partitions. This is useful to prevent one Web application from accessing the private COM+ applications, configuration information, and data of another Web application. COM+ partitions can hold different versions of your own custom COM components. For example, if you host Web sites for two competing companies that both use COM+ in their Web applications, you can use COM+ partitions to ensure that one company's Web application cannot access the COM+ components in the other company's Web applications. If one of those companies asks you to change certain features in a COM+ application that they both use, you can isolate the new version of that COM+ application in the partition that is linked to their Web application.

To enable COM+ partitions on the IIS side, set the AspUsePartition flag of the AspAppServiceFlags Metabase Property at the application level. The partition is identified by a GUID (created using the Component Services Manager snap-in), which can be set at the AspPartitionID Metabase Property. If no partition is specified, the default system partition is used. For more information, please see "Creating and Configuring COM+ Partitions" in the COM+ SDK or online at COM+ (Component Services).

Important

Only one version of a COM+ component can be used in any application pool, even though this feature is configurable at the application level. For example, if application App1 uses version 1.0 of a custom COM+ application called Shop.dll, and application App2 uses version 2.0 of Shop.dll, then App1 and App2 should not be in the same application pool. If they are, the application that is loaded first has its version of Shop.dll loaded, and the other application is forced to use it until the applications are unloaded.

The following example enables partitions on the Default Web Site application (W3SVC/1/ROOT). Notice that after setting only the AspEnableTracker property, the AspAppServiceFlags property changes as well.

    On Error Resume Next
    set providerObj = GetObject("winmgmts://MyMachine/root/MicrosoftIISv2")
    ' Get a reference to the ASP application called Default Web Site
    set IIsWebVirtualDirSettingObj = providerObj.get("IIsWebVirtualDirSetting='W3SVC/1/ROOT'")
    WScript.Echo "Before: AspUsePartition = " & IIsWebVirtualDirSettingObj.AspUsePartition
    WScript.Echo "        AspPartitionID = " & IIsWebVirtualDirSettingObj.AspPartitionID
    WScript.Echo "        AspAppServiceFlags = " & IIsWebVirtualDirSettingObj.AspAppServiceFlags
    ' Set the ASP application to enable COM+ partitioning
    IIsWebVirtualDirSettingObj.AspUsePartition = 1
    ' Set the AspPartitionID property to the GUID configured in Component Services Manager
    ' when you created the COM+ partition
    IIsWebVirtualDirSettingObj.AspPartitionID = "{00000000-0000-0000-0000-000000000000}"
    ' Save the values to the IIS metabase
    IIsWebVirtualDirSettingObj.Put_()
    ' Get the reference again in order to refresh the AspAppServiceFlags property.
    set IIsWebVirtualDirSettingObj = Nothing
    set IIsWebVirtualDirSettingObj = providerObj.get("IIsWebVirtualDirSetting='W3SVC/1/ROOT'")
    WScript.Echo "After: AspUsePartition = " & IIsWebVirtualDirSettingObj.AspUsePartition
    WScript.Echo "       AspPartitionID = " & IIsWebVirtualDirSettingObj.AspPartitionID
    WScript.Echo "       AspAppServiceFlags = " & IIsWebVirtualDirSettingObj.AspAppServiceFlags

Tracker:

COM+ tracker allows administrators or developers to debug ASP applications. For example, if a Web application is causing problems on your server, you can enable COM+ tracker to determine when ASP pages are being loaded, when COM components are loaded, and when threads leave a page. After you have debugged your application, you can disable COM+ tracker to return your application to normal performance speed.

To enable COM+ tracker on the IIS side, set the AspEnableTracker flag of the AspAppServiceFlags Metabase Property at the application level.

The following example enables tracking on the Default Web Site application (W3SVC/1/ROOT). Notice that after setting only the AspEnableTracker property, the AspAppServiceFlags property changes as well:

    On Error Resume Next
    set providerObj = GetObject("winmgmts://MyMachine/root/MicrosoftIISv2")
    ' Get a reference to the ASP application called Default Web Site
    set IIsWebVirtualDirSettingObj = providerObj.get("IIsWebVirtualDirSetting='W3SVC/1/ROOT'")
    WScript.Echo "Before: AspEnableTracker = " & IIsWebVirtualDirSettingObj.AspEnableTracker
    WScript.Echo "        AspAppServiceFlags = " & IIsWebVirtualDirSettingObj.AspAppServiceFlags
    ' Set the ASP application to enable COM+ tracking
    IIsWebVirtualDirSettingObj.AspEnableTracker = 1
    IIsWebVirtualDirSettingObj.Put_()
    ' Get the reference again in order to refresh the AspAppServiceFlags property.
    set IIsWebVirtualDirSettingObj = Nothing
    set IIsWebVirtualDirSettingObj = providerObj.get("IIsWebVirtualDirSetting='W3SVC/1/ROOT'")
    WScript.Echo "After: AspEnableTracker = " & IIsWebVirtualDirSettingObj.AspEnableTracker
    WScript.Echo "       AspAppServiceFlags = " & IIsWebVirtualDirSettingObj.AspAppServiceFlags

Transactions: Transaction support in ASP pages has been available since IIS version 4.0. However, IIS has changed its internal implementation of transactions to take advantage of COM+ services. IIS no longer creates a COM component to house a transaction but accesses the COM+ transaction service directly, thus greatly improving the speed of transaction processing. As always, transactions can only be configured at the page level using the @TRANSACTION directive and the events of the ASP built-in object called ObjectContext.

New Metabase Properties for ASP

The following metabase settings have been added for this release of ASP.

Metabase Property Name	Purpose
AspAppServiceFlags Metabase Property	Enables features like COM+ side-by-side assembly (formerly known as Fusion), partitioning, and so on.
AspDiskTemplateCacheDirectory Metabase Property	Specifies the location of the ASP disk cache.
AspExecuteInMTA Metabase Property	Enables ASP threads to execute in a multi-threaded apartment.
AspKeepSessionIDSecure Metabase Property	Sends the ASP session cookie to a browser securely.
AspMaxDiskTemplateCacheFiles Metabase Property	Specifies the ASP Disk cache maximum.
AspPartitionID Metabase Property	Specifies the COM+ partition to use for the application.
AspRunOnEndAnonymously Metabase Property	Enables ASP to run the global.asa Application_OnEnd and Session_OnEnd events anonymously.
AspBufferingLimit Metabase Property	Specifies the limit of the buffer size.
AspMaxRequestEntityAllowed Metabase Property	Specifies the maximum number of bytes allowed in the entity body of an ASP request.
AspSxsName Metabase Property	Allows ASP applications to specify which version of a system DLL or classic COM component to use.

ASP Debugging

Because the worker process, W3wp.exe, runs as the Network Service account in IIS 6.0 worker process isolation mode, you must configure Launch and Access permissions to enable ASP debugging for Script Debugger and Visual InterDev. For more information, see Enabling ASP Debugging.

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