Why am I getting infinite redirect loop with force_ssl in my Rails app?

I want to have my API controller use SSL, so I added another listen directive to my nginx.conf upstream unicorn { server unix:/tmp/unicorn.foo.sock fail_timeout=0; } server { listen 80 default deferred; listen 443 ssl default; ssl_certificate /etc/ssl/certs/foo.crt; ssl_certificate_key /etc/ssl/private/foo.key; server_name foo; root /var/apps/foo/current/public; try_files $uri/system/maintenance.h

[bluerabbit]

proxy_set_header X-Forwarded-Protoをnginxに設定してRailsをSSLと判断させる

[morygonzalez]

force_ssl で redirect_loop が発生するときの対処法（参考にならなかった）