Topic: Handling 30X redirection from a backend server behind a prox

[Thierry]

I search for this probably common problem without founding any "good" solution.

Configuration:
https://frontend/myapp Proxypass to http://backend/
Apache/2.4.18 (Ubuntu 16.04 LTS, in containers) for both servers.
Backend serve files as a standard Web server.

Frontend server configuration:
ProxyRequests Off
ProxyPreserveHost On
ProxyPass /myapp/ http://backend/
ProxyPassReverse /myapp/ http://backend/

Problematic:
https://frontend/myapp/foo (Directory) is redirected (HTTP 301 / Location) by backend to http://frontend/foo/ (mod_dir feature)
This redirection is wrong because it use HTTP instead of HTTPS and application prefix (myapp) is omitted -> User have a 404 error.

A solution is to redirect: https://frontend/myapp to http://backend/myapp and handle http from frondent but make a dependance between server and opening 80 port.

What is the best practice to handle this use case ?
Add some Proxy options (ProxyAddHeaders, ProxyVia) ? Add RewriteRules on backendserver ?

[Thierry]

Problem solved: bad configuration of ProxyPreserveHost from a previous configuration.
It must be left as Off.