IIS redirector error handling

[Jens Mønster Sørensen <jm...@rgm.dk>]

Hi

We have been using JServ now Tomcat for some years now and are quite happy
about it. But alas some of our customers want thier stuff running on Win NT
or Win 2000, so we have also been using the IIS redirector.

And we have found it pretty unsatisfactory that when the tomcat/java process
for some reason dies, the only thing client recives is a broken connection
and no response. Which for instance by the MS Internet Explorer is
interpreted as a DNS error.

So we wanted to change the redirector to write some kind of configurable
response to the client before cutting the connection.

Without beeing an expert on IIS, it is my impression that IIS has a standard
way of handling this. For each site and its "virtual dirs" you can for each
http error code set up a response (a local file, a URI or a URL).

Therefore my first idea was to change the redirector to just set the error
code to 503 "Service Unavailable" when it failed to connect to the Tomcat
process, and thus utilising the IIS standard way of doing it. But I was not
able to get this working.

So instead I changed the redirector to read a new string value "error_uri"
from the "Jakarta Isapi Redirector/1.0" registry key (i.e. similar to the
"extension_uri" setting), and then send this URI to the client when it is
unable to connect to the Tomcat Process. I made the change in the
jk_isapi_plugin.c which I have attached to this mail.

It has been tested and works fine on Win 2000 Server.

I regretfully haven't got the time to get very much more involved than this,
and trust that sending this mail to the tomcat-dev list should be enough to
get this change proposal (or somthing similar to it) considered for addition
to the code-base.

Thanks in advance

/Jens