IWMSCacheProxyServer::CompareContentInformation

  • Article

banner art

Previous Next

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

Previous Next