SetUserCachingKey callback function

Applies to: desktop apps only

The SetUserCachingKey callback function is used by Web filters to set the user caching key. The user caching key is the key that the request will be cached with. This key is used to check if the given request is in the cache, so there is no need to pass the request to the server. The key is also used to cache the server response after it arrives. The URL of the request is used as the default cache key.

The SetUserCachingKey callback function is declared as:


BOOL WINAPI SetUserCachingKey(
  _In_  struct _HTTP_FILTER_CONTEXT *pfc,
  _In_  LPSTR lpszCacheKey 


  • pfc [in]
    Pointer to the HTTP_FILTER_CONTEXT data structure that is associated with the current, active HTTP session. Pass the filter context in this parameter.

  • lpszCacheKey [in]
    Pointer to a null-terminated string containing the new caching key.

Return value

This callback function returns TRUE if the call is successful; otherwise, it returns FALSE. To obtain extended error information, call GetLastError.


Minimum supported client

None supported

Minimum supported server

Windows Server 2008 R2, Windows Server 2008 with SP2 (64-bit only)


Forefront Threat Management Gateway (TMG) 2010



See also

Callback Functions



Build date: 7/12/2010