xA.M. Kuchling wrote:

> On Wed, Jan 21, 2004 at 02:35:39PM -0500, Graham Fawcett wrote:
>
>>Andrew's suggestion looks like a winner: it gives a nice failover in
>>case 'Host' is not included in the request header.
>
>
> One corner case: I'm not sure what happens if a port is specified.  Does
> Host: contain "servername:8080"?  Is it OK to include the port in the
> SERVER_NAME variable?

D'oh. You're right about the Host header: it includes the port. If the
port is not specified, the default port for the service is implied.

After a re-read of the CGI spec, it turns out that SERVER_NAME is "not
request-specific and [is] set for all requests". So, according to
CGI/1.1, SERVER_NAME should not be equivalent to the Host header.

I've concluded that I don't like the CGI spec any more, and put my trust
  in de-facto standards. Namely: what does Apache/FCGI do?

I set up a quick proxy at machine1:8080 which passes requests to an
Apache server at machine2:80. Names have been changed to protect the
innocent. Not a real HTTP proxy, BTW, just used Sam Rushing's
proxy_server class from his Medusa writings.

Whipped up a quick PHP page (ugh, I know, but I don't have Python on
that machine):

HTTP_HOST: ". $_SERVER["HTTP_HOST"];
echo "
SERVER_NAME: ". $_SERVER["SERVER_NAME"];
echo "
SERVER_PORT: ". $_SERVER["SERVER_PORT"];
?>

The results were interesting. Hitting my proxy at

   http://machine1:8080/graham/test.php

machine2 returned these results:

   HTTP_HOST: machine1:8080
   SERVER_NAME: machine1
   SERVER_PORT: 80

I assume that the PHP interpreter did not fiddle with the results.

The SERVER_PORT is the port that Apache is listening on, not the port
from my Host header. Interesting, but to be fair I wasn't using a real
HTTP proxy; maybe it would have responded differently... but maybe not.

In conclusion, Apache/FGCI uses the hostname in HTTP_HOST to set the
SERVER_NAME variable, and thus is in flagrant violation of the
"non-request-specific" directive in the CGI spec. ;-) Futhermore, it
does not include the port in SERVER_NAME. QED.

I'd suggest that http_request.py be changed to use HTTP_HOST instead of
SERVER_NAME for any redirects, if HTTP_HOST is present.

-- Graham