Shibboleth Developers

["Howard Gilbert" <>]

> But what happens if ASP.NET is disabled? There must be some kind of
> fallback
> to more typical behavior.

The trick happens at two levels. First, there is the ISAPI mapping to
extensions, and when none of the extensions match specifically configured
ISAPI modules then a default ISAPI module is selected that just sends back
the file.

Then the trick is played a second time for extensions that are mapped to
ASP.NET (which is just an ISAPI module that hosts this particular execution
environment). It now runs through the ASP.NET XML configuration looking for
mappings of file extensions to ASP.NET execution enviroments (ASPX to the
HTML server, ASMX to the Web Services), but when it comes to the end of the
line everything else is handled by the ASP.NET version of "just send the
named file back".

When you add a new file extension to ASP.NET you have to configure it in two
places. Once to the XML so it runs in the right .NET execution pipeline, and
once again in the ISAPI mapping of IIS connecting the extension to ASP.NET
itself.

The result is that there is no "data only" directory in IIS. Every URL gets
processed through at least the ISAPI mappings, but to do that it has to be
sent to some application address space even if its just the default.