I have Apache 2.2 set up as a reverse proxy, forwarding POST'ed packets to an internal server, getting the response, and sending it back. Everything works fine when no errors occur. To handle HTTP 500 error codes, I have configured ProxyErrorOverride to replace the internal server's page with our own custom error. A Perl CGI script does that. And it works mostly fine.
But it looks like I have no access to the original packet. I'd like to log that request and send alerts. I have a lot of info available for the original packet: for example $ENV{'Content-Length'} returns the size of it. But when I try to read STDIN to get the actual content sent by the POST, like a regular ErrorDocument could do for locally-served CGI, I get nothing . Any way around this?