IWMSCacheProxy::AddCacheItem
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IWMSCacheProxy::AddCacheItem
The AddCacheItem method is called by the server to prestuff a cache.
Syntax
HRESULT AddCacheItem( BSTR bstrOriginUrl , BSTR bstrPrestuffUrl , long lExpiration , long lBandwidth , long lRemoteEventFlags , IWMSCacheProxyCallback* pCallback , VARIANT varContext );
Parameters
bstrOriginUrl
[in] BSTR containing the URL on the origin server of the content to be cached.
bstrPrestuffUrl
[in] BSTR containing the URL identifying the location for the cache. If NULL, the method uses bstrOriginUrl.
lExpiration
[in] long containing the amount of time, in seconds, that the cache item is available to be streamed after it has been cached. For example, a value of 86,400 indicates that cached content can be streamed for 24 hours after it is downloaded from the origin server.
lBandwidth
[in] long containing the maximum bandwidth that the server can use when streaming content into cache storage.
lRemoteEventFlags
[in] long containing the remote events that must be passed back to the origin server. This must be one of the following values. For more information, see the WMS_EVENT_TYPE enumeration value.
| Event | Description |
| WMS_EVENT_REMOTE_CACHE_OPEN | A remote cache proxy server has opened cached content or established a connection to an upstream server. |
| WMS_EVENT_REMOTE_CACHE_CLOSE | A remote cache proxy server has closed a content file or disconnected a client from an upstream server. |
| WMS_EVENT_REMOTE_CACHE_LOG | A client submitted a rendering log to indicate that it streamed content from a local cache, or a cache proxy server submitted a remote log to indicate that it either streamed content from cache or proxied it from an upstream server. |
pCallback
[in] Pointer to an IWMSCacheProxyCallback interface. This can be NULL if no callback is requested.
varContext
[in] VARIANT containing a value defined by the server to identify which call to AddCacheItem the plug-in is responding to when it calls IWMSCacheProxyCallback::OnAddCacheItem. The plug-in must pass this value back unaltered.
Return Values
If the method succeeds, the plug-in must return S_OK. To report an error, the plug-in can return any HRESULT other than S_OK. If the plug-in uses the IWMSEventLog interface to log error information directly to the Windows Event Viewer, it is recommended that it return NS_E_PLUGIN_ERROR_REPORTED. Typically, the server attempts to make plug-in error information available to the server object model, the Windows Event Viewer, and the troubleshooting list in the details pane of the Windows Media Services MMC. However, if the plug-in uses the IWMSEventLog interface to send custom error information to the Windows Event Viewer, returning NS_E_PLUGIN_ERROR_REPORTED stops the server from also logging to the event viewer. For more information about retrieving plug-in error information, see Identifying Plug-in Errors.
Remarks
This plug-in can be called whenever an item must be added to a cache. It is always called by the server when the IWMSCacheProxyPlugin::PreStuff method is called. The plug-in calls IWMSCacheProxyCallback::OnAddCacheItem to respond to the AddCacheItem method.
Example Code
if (FAILED(hr)) goto EXIT;
if (FAILED(hr)) goto EXIT;
EXIT:
// TODO: Release temporary objects.
return(hr);
Requirements
Header: streamcache.h.
Library: WMSServerTypeLib.dll.
Platform: Windows Server 2003, Enterprise Edition; Windows Server 2003, Datacenter Edition; Windows Server 2008.
See Also
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