Hi Torsten,
An ErrorDocument is an internal redirect. These REDIRECT_... environment
variables are copied from the previous ($r->prev) request's
$r->subprocess_env just by copying everything and prepending REDIRECT_
to each key. So if the original request has an environment variable
named REQUEST_URI the error document should have a REDIRECT_REQUEST_URI,
see rename_original_env() in httpd-x.y/modules/http/http_request.c.
Since REQUEST_URI is the standard CGI environment variable (see
ap_add_cgi_vars() httpd-x.y/server/util_script.c) I'd take
REDIRECT_REQUEST_URI.
As it turned out, I was (entirely) wrong when I thought it is
working. It was wishfull thinking - but not a real solution - neighter one
of the REQUEST_URI, REDIRECT_URL and/or REDIRECT_QUERY_STRING environment
variables seemed to be good enough for a mod_rewrite solution, or at least
I was unable to build one. (I just made some errors in testing and
repeatedly out- and out-out-commenting various httpd.conf setting, but it
wasn't _really_ working whein I thought it would).
Summing up what I have so far ( which might be incomplete or even wrong):
looking for a cheap/good/working solution for a way to solve what
http://httpd.apache.org/docs/2.2/rewrite/rewrite_guide_advanced.html
describes under the title "Redirect Failing URLs to Another Web Server",
but with the (it seems important) difference that I want to hide the new
server from the eyes of the customers and as such _proxy_ the failing
requests instead of redirecting, the given receipt
RewriteEngine on
RewriteCond %{REQUEST_URI} !-U
RewriteRule ^(.+) http://webserverB.dom/$1
shows up to NOT work when I attempted to make it
RewriteEngine on
RewriteCond %{REQUEST_URI} !-U
RewriteRule ^(.+) http://webserverB.dom/$1 [P]
Neither was I able to use the Error_Document trick you sugegsted and use
Rewrite on/with it.
I've given up my first attempt - the earlier in the thread shown
PerlResponse handler - as I was unable to output the Content-Type header
as 'text/html'; I haven't however tried the solution suggested with adding
an extra filter for the end phase to substitute the 'text/plain' that I
was seeing and which actually generated the initial question for this
thread and it's subject.
I finally went the 'standard way' [?] and added
ErrorDocument 404 /cgi-bin/404_to_oldserver.pl
in httpd.conf, making /cgi-bin/404_to_oldserver.pl to be
----------------------------
#!/usr/bin/perl
use LWP::UserAgent;
my $ua = LWP::UserAgent->new;
my $url = $ENV{'REQUEST_URI'};
$url = "http://OLD.SERVER.COM/$url"; ;
my $response = $ua->get( $url );
my $body = $response->content;
my $h = $response->{'_headers'};
$h->push_header( 'Status' => $response->code );
my $header = $h->as_string;
print $header;
print "\n";
print $body;
1;
-----------------------------------------------
This way might have it's own special problems too, but at least it seems
to work OK so far and give me a start.
I'm still [a bit] convinced that a mod_perl solution might or should be
available and be both better and more effective, but I wasn't able to get
it working - even after spending much more effort than I thought initially
that it will take - and gave up for now.
Many thanks to all those that offered advice or help.
Iosif Fettich
PS. Firebug once again proved to be an invaluable resource in helping
understand what's up and find a solution.
