Need help to manage poorly written apps behind Apache used as Reverse Proxy

["Alan AZZERA" <azzera.alan@xxxxxxxxx>]

Hi world !

First, please forgive my poor written English. Here is my problem, I hope someone could help me.

I need to host some web apps, coded in PHP by non-professional developpers, and sometimes poorly written and designed. I use an Apache server configured as a Reverse Proxy, my real HTTP server is behind this 
R.P. I have two DNS zone, a public one and a private one. Here is the chain :

1. Client's web browser asks for http://app.public.zone/
2. My Apache RP has a Virtual Host (ServerName app.public.zone) that catches the request, and (reverse)proxifies it to http://app.private.zone/
3. My Apache private server has a VirtualHost (Servername app.private.zone) that handles the request.

Everything works fine with well coded and designed PHP apps, that make use of right Apache environment variables like HTTP_X_FORWARDED_(HOST|SERVER). But apps that make use of SCRIPT_URI, SERVER_NAME or HTTP_HOST cause troubles. I tried to handle these troubles with mod_proxy_html, but I failed to configure it to rewrite efficiently URL in CSS or _javascript_s. Desperate, I tried to handle this with mod_rewrite and its [E=HTTP_HOST:
app.public.zone] feature in the VirtualHost app.private.zone. It failed too.

Do I miss something obvious ? Am I trying to solve problems the wrong way ? Since I am not far for being a newbie, it is very possible... Would anyone be keen enough to put me on the right way ?

Best regards,

Al.