IWMSCacheProxyServer::CompareContentInformation
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IWMSCacheProxyServer::CompareContentInformation
The CompareContentInformation method is called by the cache plug-in to determine whether content is up to date.
Syntax
HRESULT CompareContentInformation( BSTR bstrOriginUrl , IWMSContext* pContentInfo , IWMSContext* pPresentationContext , IWMSCacheProxy* pICacheProxy , IWMSProxyContext* pIProxyContext,IWMSCacheProxyServerCallback*pCallback,VARIANTvarContext);
Parameters
bstrOriginUrl
[in] BSTR containing the URL of the content on the origin server.
pContentInfo
[in] Pointer to an IWMSContext interface containing a content description context.
pPresentationContext
[ni] Pointer to an IWMSContext interface containing a presentation context.
pICacheProxy
[in] Pointer to the plug-in making the call.
pIProxyContext
[in, optional] Pointer to an IWMSProxyContext interface that enables the server to retrieve client credentials and the name and port number of the proxy server that handles the client request.
pCallback
[in, optional] Pointer to an IWMSCacheProxyServerCallback interface. The server calls IWMSCacheProxyServerCallback::OnCompareContentInformation to respond to the plug-in.
varContext
[in, optional] VARIANT containing a value defined by the plug-in. For example, your plug-in can use this parameter to persist state information. The server does not alter this value and passes it back when calling IWMSCacheProxyServerCallback::OnCompareContentInformation.
Return Values
If the method succeeds, it returns S_OK. If it fails, it returns an HRESULT error code.
| Return code | Number | Description |
| E_INVALIDARG | 0x80070057 | The bstrOriginUrl, pICacheProxy, pCallback, pContentInfo, or pPresentationContext parameter is NULL. |
| E_OUTOFMEMORY | 0x8007000E | The server could not allocate memory. |
Example Code
// Retrieve a pointer to a content description context for
// a specific cache entry in the cache database. The database
// and the GetContentInfo() function are user-defined.
hr = m_pCacheEntry->GetContentInfo(&pContentInfo);
// Retrieve the requested URL and preferred protocol from
// local variables. HTTP and RTSP are common protocols.
bstrUrl =.m_pszPreferredProtocol;
bstrUrl.Append( L"://" );
bstrUrl.Append(m_bstrContent );
// Direct the cache proxy server to compare the cached
// content to content on the origin server.
hr = m_pICacheProxyServer->CompareContentInformation(
bstrUrl,
pContentInfo,
m_pPresentationContext,
this,
(IWMSProxyContext*) this,
this,
varContext
);
Requirements
Header: streamcache.h.
Library: WMSServerTypeLib.dll.
Platform: Windows Server 2003, Enterprise Edition; Windows Server 2003, Datacenter Edition; Windows Server 2008.
See Also
- IWMSCacheProxyServer Interface
- IWMSCacheProxyServerCallback Interface
- IWMSCacheProxyServerCallback::OnCompareContentInformation
- IWMSContext Interface
- Presentation Context
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