# optional:
# internal redirect to /login if there is a auth failure, delete or comment this out if you don't want this behaviour and just show a generic 401 error
error_page 401 /login;

location / {
    auth_request /auth;

    # pass Set-Cookie headers from the subrequest response back to requestor
    auth_request_set $auth_cookie $upstream_http_set_cookie;
    add_header Set-Cookie $auth_cookie;

    auth_request_set $auth_status $upstream_status;

    try_files $uri $uri/ /index.html;
}

location = /auth {
    # internaly only, /auth can not be accessed from outside
    internal;

    # internal proxy to auth-server running on port 3000, responses expected from proxy:
    #   2xx response = access allowed via auth_request
    #   401 or 403 response = access denied via auth_request
    #   anything else = error
    proxy_pass http://localhost:3000;

    # don't pass request body to proxied server, we only need the headers which are passed on by default
    proxy_pass_request_body off;

    # there is no content length since we stripped the request body
    proxy_set_header Content-Length "";

    # let proxy server know more details of request
    proxy_set_header X-Original-URI $request_uri;
    proxy_set_header X-Original-Remote-Addr $remote_addr;
    proxy_set_header X-Original-Host $host;
}

# these are handled by the proxy as part of the auth routines
location ~ ^/(login|logged-in|logout)$ {
    proxy_pass http://localhost:3000;
    proxy_set_header X-Original-URI $request_uri;
    proxy_set_header X-Original-Remote-Addr $remote_addr;
    proxy_set_header X-Original-Host $host;
}

# this CSS is used by the three requests above and is served by the proxy
location = /css/skeleton.css {
    proxy_pass http://localhost:3000;
}

# optional location block
# if you have other location blocks, be sure to add auth_request there too otherwise these requests won't get protected, for example
location ~* \.(js|css|png|jpg|jpeg|gif|ico)$ {
    expires 90d;
    log_not_found off;
    auth_request /auth;
}