IWMSDataContainerVersion Object (Visual Basic .NET)
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IWMSDataContainerVersion Object (Visual Basic .NET)
The IWMSDataContainerVersion object contains methods that enable you to specify and retrieve content information that can be used when checking whether a cached item is current. The following list provides an overview of this process:
- The client requests content that is stored in a file on both a cache server and the origin server.
- The cache server calls IWMSCacheProxy.QueryCache on the first enabled plug-in.
- The plug-in determines whether the content is cached. Assume a cache hit.
- The plug-in creates an IWMSDataContainerVersion object, retrieves information about the content on the cache server, and specifies the data members in the IWMSDataContainerVersion object.
- The plug-in checks the expiration date on the cached content. If it has not expired, the plug-in can call IWMSCacheProxyCallback.OnQueryCache and direct the server to stream the content. If it has expired, the plug-in calls IWMSCacheProxyServer.CompareContentInformation to determine whether the content is current.
- If the plug-in calls CompareContentInformation, the cache server calls the origin server to retrieve content information.
- The origin server calls IWMSDataSourcePlugin.GetDataContainerVersion on the appropriate data source plug-in, as determined by the data type associated with the physical URL of the requested content.
- The data source plug-in creates an IWMSDataContainerVersion object, retrieves information about the content on the origin server, and specifies the data members in the IWMSDataContainerVersion object. The origin server sends the information, including a pointer to the IWMSDataContainerVersion object, back to the cache server in a cache content information context.
- The cache server calls IWMSDataContainerVersion.Compare to compare the contents of the two IWMSDataContainerVersion objects.
- The cache server calls IWMSCacheProxyServerCallback.OnCompareContentInformation to indicate whether the content is current.
The IWMSDataContainerVersion object is implemented by the server.
- Note This object is available only on Windows Server 2003, Enterprise Edition; Windows Server 2003, Datacenter Edition; and Windows Server 2008.
The IWMSDataContainerVersion object exposes the following properties and methods.
| Method | Description |
| Compare | Compares two IWMSDataContainerVersion objects to determine whether they are equal. |
| GetCacheFlags | Retrieves flags that indicate whether content can be cached, proxied, or split. |
| GetContentSize | Retrieves the size of the content in bytes. |
| GetEntityTagCount | Retrieves an entity tag, given an index number. |
| GetEntityTag | Retrieves the number of entity tags. |
| GetExpirationTime | Retrieves the content expiration date. |
| GetLastModifiedTime | Retrieves the time at which the content was last modified. |
| SetCacheFlags | Specifies flags that indicate whether content can be cached, proxied, or split. |
| SetContentSize | Specifies the size of the content in bytes. |
| SetEntityTag | Specifies an entity tag. |
| SetExpirationTime | Specifies the content expiration date. |
| SetLastModifiedTime | Specifies the time at which the content was last modified. |
See Also
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