What's New in ASP

Article
09/14/2006

In addition to internal performance enhancements and optimizations, this version of 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

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. IIS 6.0 has the ability to solve the problem of hung threads by recycling the worker process that hosts that particular instance of the ASP ISAPI extension, ASP.dll. When ASP threads are hung in IIS 6.0, ASP.dll will call the ISAPI server support function 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 Note Note that hung threads are different from long-running scripts that eventually time out. Hung threads are not responsive to timeouts. Recycling the worker process is therefore the only option, and ASP initiates recycling under such circumstances.

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 at systemroot\System32\inetsrv\ASP Compiled Templates, if you installed your operating system on the C: drive. 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, 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:

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 MDAC, MFS, MSVCRT, MSXML, and so on. 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](aa649610\(v=vs.71\).md).

To enable them by using IIS Manager, use the following procedure:

1.  Right-click a Web site or virtual directory and click **Properties**.
2.  Click the **Virtual Directory** tab, and click **Configuration**. If the configuration button is not enabled, it is because you have not created an application for this virtual directory. Click **Create** to create an application.
3.  In the **Application Configuration** dialog box, click the **Options** tab, and select **Enable Side by Side assemblies**.
4.  In the **Manifest file name** box, type the file name of the COM+ manifest file, and click **OK** twice.

To enable side-by-side assemblies programmatically, set the **AspEnableSxs** flag of the [AspAppServiceFlags](aa694992\(v=vs.71\).md) metabase property. Also set the [AspSxsName](aa695054\(v=vs.71\).md) metabase property to the name of the COM+ manifest name. Set both metabase properties at the application level.

![important](images/Aa690674.important(en-us,VS.71).gif) **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:

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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 who 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 the topic titled 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. Once 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:

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 Object

New Metabase Properties for ASP

The following metabase settings have been added for this release:

Metabase Property Name	Purpose
AspAppServiceFlags	For features like COM+ side-by-side assembly (formerly known as Fusion), partitioning, and so on.
AspDiskTemplateCacheDirectory	Location of the ASP disk cache.
AspExecuteInMTA	To enable ASP threads to execute in a multi-threaded apartment.
AspKeepSessionIDSecure	To send the ASP session cookie to a browser securely.
AspMaxDiskTemplateCacheFiles	ASP Disk cache maximum.
AspPartitionID	COM+ partition to use for the application.
AspRunOnEndAnonymously	To enable ASP to run the global.asa Application_OnEnd and Session_OnEnd events anonymously.

What's New in ASP

Better International and UTF-8 Support

Improved POST Support

ASP Hang Detection

Caching of Popular Files

UNC Enhancements

COM+ Services in ASP

New Metabase Properties for ASP

Additional resources