Microsoft Internet Security and Acceleration Server 2000


The implemenation of ISAPI in ISA Server allows you to accumulate request chunks, to form a complete request, by means of a Web filter.

The Webresponsemodifier filter collects the response chunks and then allows you to change them depending on the complete response. This filter is an adaptation of the filter that IIS uses for compression. (Original filter was written by David Treadwell in July 1997.)

The filter works with two notifications. In SF_NOTIFY_Send_Raw_Data, it collects the response's chunks, but sends 0 bytes instead of the chunks. Then, when all the chunks of this response have passed SF_NOTIFY_Send_Raw_Data notifications, ISA Server thinks the complete response was sent. It therefore calls the SF_NOTIFY_End_Of_Request notification. The filter sends the complete response in the SF_NOTIFY_End_Of_Request notification.