Re: what's a CGI to do?...

Dave Kristol (dmk@allegra.att.com)
Thu, 30 Nov 95 17:24:43 EST

drtr1@cus.cam.ac.uk (David Robinson) wrote:
> > [DMK]
> >...
> >Let me paraphrase the problem. NCSA httpd (and my server) allow a CGI
> >to give a "local" Location: header that causes the server to process
> >the resulting redirection without first sending anything to the client.
> >Beyond that I think the "correct" behavior is undefined. So I'm trying
> >to define it.
> >
> >Some questions that come up are:
> >
> >1) What should the method be for the redirected request?
> >(N.B. I think the behavior should be consistent with what happens for a
> >"full" URL that gets returned to a client.)
>
> A "GET" method. It's the only useful behaviour; the CGI script has no means
> for supplying content.
Which means you disagree with Koen Holtmann. And this apparently violates
the idea that the local redirect should do what the user-agent would do.
>
> >2) If the method should indeed be POST, where does the content come from?
> >(POST requires Content-Type and Content-Length headers.)
>
> Logically, from the script that returned the Location: header. Unfortunately,
> there is currently no way to arrange that.
Repeat previous remarks here.
>
> >3) Should there be a way for a CGI to specify the method to use with a
> >redirection? If yes, only for local URLs, or for full ones, too?
>
> You could do it for local URLs by having a Method: header, and taking
> any content produced by the CGI script as input content for the redirected
> request.
>
> > 4) What environment should be passed to a CGI (like T2 above) that is
> > reached via a redirection?
> > (Here again, I think it should be the same as if a full URL got sent
> > back to the client, and the client made a new request.)
>
> Yes. That is what servers currently do on internal redirection. However, some
> servers also pass the CGI variables for the original request prefixed by
> REDIRECT_. e.g. Client requests http://foo.com/script?args
> The server (perhaps because of script being a CGI script returning a
> Location: /bar header) internally redirects this to the CGI script
> http://foo.com/bar
> then this script gets the environment variables
> SCRIPT_NAME=/bar
> QUERY_STRING=""
> REDIRECT_SCRIPT_NAME=/script
> REDIRECT_QUERY_STRING=args

Interesting. What server does that?

Dave Kristol