You may want to write your own handler if you are an IIS server administrator who wants the default RDS support, but more control over user requests and access rights.
The MSDFMAP.Handler implements the IDataFactoryHandler interface.
This interface has two methods, GetRecordset and Reconnect. Both methods require that the CursorLocation property be set to adUseClient.
Both methods take arguments that appear after the first comma in the "Handler=" keyword. For example, "Handler=progid,arg1,arg2;" will pass an argument string of "arg1,arg2", and "Handler=progid" will pass a null argument.
This method queries the data source and creates a new Recordset object using the arguments provided. The Recordset must be opened with adLockBatchOptimistic, and must not be opened asynchronously.
Arguments
conn The connection string.
args The arguments for the handler.
query The command text for making a query.
ppRS The pointer where the Recordset should be returned.
This method updates the data source. It creates a new Connection object and attaches the given Recordset.
Arguments
conn The connection string.
args The arguments for the handler.
pRS A Recordset object.
This is the interface definition for IDataFactoryHandler that appears in the msdfhdl.idl file.
[
uuid(D80DE8B3-0001-11d1-91E6-00C04FBBBFB3),
version(1.0)
]
library MSDFHDL
{
importlib("stdole32.tlb");
importlib("stdole2.tlb");
// TLib : Microsoft ActiveX Data Objects 2.0 Library
// {00000200-0000-0010-8000-00AA006D2EA4}
#ifdef IMPLIB
importlib("implib\\x86\\release\\ado\\msado15.dll");
#else
importlib("msado20.dll");
#endif
[
odl,
uuid(D80DE8B5-0001-11d1-91E6-00C04FBBBFB3),
version(1.0)
]
interface IDataFactoryHandler : IUnknown
{
HRESULT _stdcall GetRecordset(
[in] BSTR conn,
[in] BSTR args,
[in] BSTR query,
[out, retval] _Recordset **ppRS);
// DataFactory will use the ActiveConnection property
// on the recordset after calling Reconnect.
HRESULT _stdcall Reconnect(
[in] BSTR conn,
[in] BSTR args,
[in] _Recordset *pRS);
};
};