How to do rewrites in an IIS ISAPI

Note to self: If ever you need to do a rewrite in an IIS ISAPI Filter you just need to re-set the pHeaderInfo's url header. Something like this:

 
pHeaderInfo->GetHeader(pCtxt->m_pFC,
              "url",strUrl.GetBuffer(dwUrlSize+1),&dwUrlSize);
strUrl.ReleaseBuffer(); 
strNewUrl = GET_REWRITE_FOR_URL(strUrl); 
if ( strNewUrl.IsEmpty() == FALSE ) {  
    pHeaderInfo->SetHeader(pCtxt->m_pFC, 
              "url", (LPTSTR)(LPCTSTR)strNewUrl);  
} 
return SF_STATUS_REQ_NEXT_NOTIFICATION; 

This is working in IIS4 and above.

Note that if you really need a good re-write/redirect filter for IIS you should look at IIRF ,but since it's not working for IIS4 i had to do this manually