Add the Web Filter to ISA Server

The DllRegisterServer and DllUnregisterServer functions in the WebResponseModifier sample both call RegisterWebFilter. RegisterWebFilter receives a Boolean value. True indicates that the filter should be added to ISA Server, and false indicates that it should be removed. RegisterWebFilter uses the ISA Server administration COM objects.

The following RegisterWebFilter function code is taken from the file WebFltrRegister.cpp, included in the Webresponsemodifier folder:

// Define the filter GUID and the filter's path relative to 
// the ISA installation folder.
const char StrGuid[] = "{87F18571-C71D-4a2f-9111-9E0927A00B51}";
const char FilterRelativePath[] = "WebResponseModifier.dll";

HRESULT RegisterWebFilter(bool fRegister)
{
	HRESULT hr = S_OK;

	// Get instance of filter admin object.
	hr = CoInitialize(NULL);

	if (FAILED(hr))
	{
		return hr;
}
	else
	{
		ISALIB::IFPCPtr pIISA;

		hr = CoCreateInstance(
			ISALIB::CLSID_FPC,
			NULL,
			CLSCTX_INPROC_SERVER,
			ISALIB::IID_IFPC,
			(void**)&pIISA);

		if (FAILED(hr) || (pIISA == NULL))
		{
			CoUninitialize( );
			return hr;
	}

		ISALIB::IFPCArrayPtr pIISAArr; 
		ISALIB::IFPCExtensionsPtr pIExtensions;
		ISALIB::IFPCWebFiltersPtr pWebFilters;   
		ISALIB::IFPCWebFilterPtr pFilter;

		try
		{
			pIISAArr = pIISA->GetContainingArray(); 
			pIExtensions = pIISAArr->Extensions;
			pWebFilters = pIExtensions->WebFilters;   
	}
		catch(_com_error& err)
		{
			hr = err.Error();
			CoUninitialize( );
			return hr;
	}

		if (fRegister)
		{
			try
			{
				pFilter = pWebFilters->Add(StrGuid,"Web Response modifier",FilterRelativePath,ISALIB::fpcFilterPriority_Medium,ISALIB::fpcFilterDirectionBoth);
				pFilter->PutDescription("Modifies the web servers' response");
				pFilter->PutVendor("Microsoft (R) Corporation");
				pFilter->PutVersion("4.0"); 						
				pFilter->Save(VARIANT_FALSE, VARIANT_TRUE); 			
		}
			catch(_com_error& err)
			{
				if(err.Error() != HRESULT_FROM_WIN32(ERROR_ALREADY_EXISTS))
				{
					hr = err.Error();
			}
		}
		else
		{
			try
			{
				pWebFilters->Remove(StrGuid);
				pWebFilters->Save(VARIANT_FALSE, VARIANT_TRUE);
				pWebFilters->Refresh();  
		}
			catch(_com_error& err)
			{
				if(err.Error() != HRESULT_FROM_WIN32(ERROR_FILE_NOT_FOUND))
				{
					hr = err.Error();
			}
		}
	}	 
}

	CoUninitialize( );
	return hr;
}