The ILogPlugin::QueryExtraLoggingFields method determines logging information that is specific to a custom logging module.
virtual HRESULT STDMETHODCALLTYPE QueryExtraLoggingFields(
PDWORD cbSize //size of the szParameters parameter
PCHAR szParameters //defines additional fields for logging
);
You can use this method to record data sent by custom headers from the client. For example, to capture a user's cookie, the szParameters parameter would contain the following:
User-Agent\0Cookie\0\0
You could then use the IInetLogInformation::GetExtraHTTPHeaders method to retrieve a list of header information. This list would be null delimited.
IInetLogInformation::GetExtraHTTPHeaders