Adding custom HTTP headers to nginx X-Accel-Redirect
Use add_header Content-MD5 $upstream_http_content_md5;
Since X-Accel-Redirect causes internal redirect nginx will not send returned headers, but it will keep them in $upstream_http_... variables. So you could use them.
I've tried accepted answer and it doesn't work for me. But this works:
set $authorization "$upstream_http_authorization"; proxy_set_header Authorization $authorization; # Pass on secret from back end(copy-pasted from this article https://clubhouse.io/developer-how-to/how-to-use-internal-redirects-in-nginx/)
It's interesting that it's important to extract variable. This does not work for me:
proxy_set_header Authorization "$upstream_http_authorization";