using mercure from frankenphp docker image behind a reverse proxy

[abda11ah]

Hi,
I'm trying to make mercure works since it is already integrated into the frankenphp docker image.

Here is my Caddyfile that is mounted into /etc/caddy/Caddyfile :

{
	frankenphp run --https #{
 #       num_threads 4
    #    worker {
    #        num 4
    #    }
 #   }
	#auto_https off
	auto_https disable_redirects
}

mydomain.fr {
	# Handle Mercure requests first
	handle /.well-known/mercure* {
		@options {
			method OPTIONS
		}
		handle @options {
		#	header Access-Control-Allow-Origin "https://mydomain.fr"
			header Access-Control-Allow-Methods "GET, POST, OPTIONS"
			header Access-Control-Allow-Headers "Authorization, Content-Type"
			header Access-Control-Allow-Credentials "true"
			header Access-Control-Max-Age "86400"
			respond "" 204
		}
		
		reverse_proxy localhost:3000 {
		#	header_up Access-Control-Allow-Origin "https://mydomain.fr"
			header_up Access-Control-Allow-Methods "GET, POST, OPTIONS"
			header_up Access-Control-Allow-Headers "Authorization, Content-Type"
			header_up Access-Control-Allow-Credentials "true"
			
			transport http {
				read_timeout 30s
				write_timeout 30s
				dial_timeout 10s
			}
		}
	}

	tls {
		protocols tls1.3
	}

	php_server

	# General handling for other requests
	handle {
		try_files {path} {path}/ /index.php
	}

	root * /app/html/public
	encode zstd br gzip
	file_server

	@static {
		file extension .js .css .png .jpg .jpeg .gif .ico .svg
	}

	log {
		output file /var/log/caddy/access.log {
			roll_size 10mb
			roll_keep 5
			roll_keep_for 720h
		}
		level error
	}

	handle @static {
		header Cache-Control "max-age=31536000"
	}

	# Error handling
	handle_errors {
		@404 {
			expression {http.error.status_code} == 404
		}
		rewrite @404 /404
		file_server
	}

	{$CADDY_SERVER_EXTRA_DIRECTIVES}
}

http://localhost:3000 {
	mercure {
		# Publisher JWT key
		publisher_jwt 8f9e0a1b2c3d4e5f6a7b8c9d0e1f2a3b4c5d6e7f8a9b0c1d2e3f4a5b6c7d8e9f
		# Subscriber JWT key
		subscriber_jwt 9f0e1a2b3c4d5e6f7a8b9c0d1e2f3a4b5c6d7e8f9a0b1c2d3e4f5a6b7c8d9e0f1a
		# Enable heartbeat with 30s interval
		heartbeat_interval 30s
		# Allow anonymous subscribers
	#	allow_anonymous_subscribers
		authorization {
			header Authorization
			query_param token
		}
		health_check /healthz
		# Enable CORS
		cors {
			origin *
			methods GET, POST, OPTIONS
			allow_headers Authorization, Content-Type
			allow_credentials true
			max_age 86400
		}
	}

	# Handle OPTIONS requests
	@options {
		method OPTIONS
	}
	handle @options {
		header Access-Control-Allow-Origin "*"
		header Access-Control-Allow-Methods "GET, POST, OPTIONS"
		header Access-Control-Allow-Headers "Authorization, Content-Type"
		header Access-Control-Allow-Credentials "true"
		header Access-Control-Max-Age "86400"
		respond "" 204
	}

	# Handle Mercure requests
	handle /.well-known/mercure* {
		reverse_proxy localhost:3000 {
			header_up Access-Control-Allow-Origin "*"
			header_up Access-Control-Allow-Methods "GET, POST, OPTIONS"
			header_up Access-Control-Allow-Headers "Authorization, Content-Type"
			header_up Access-Control-Allow-Credentials "true"
			
			transport http {
				read_timeout 30s
				write_timeout 30s
				dial_timeout 10s
			}
		}
	}
}


# HTTP to HTTPS redirect
#:80 {
#    redir https://{host}{uri} permanent
#}

As you can see Mercure is behind the caddy reverse proxy. It is accessible only from the frankenphp shell.
inside the frankenphp docker shell i can see it is working since i'm getting 404 errors from frankenphp for all URLs but for URLs beginnning with /.well-known/mercure* i'm getting HTTP 200 OK but the length of the response is always 0 bytes.

I installed httpie package via apt

root@57729b3b5377:/app# http "https://mydomain.fr/.well-known/mercure?topic=chat/user/3/updates&token=eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9.eyJtZXJjdXJlIjp7InN1YnNjcmliZSI6"
HTTP/1.1 200 OK
Alt-Svc: h3=":443"; ma=2592000
Content-Length: 0
Date: Mon, 13 Jan 2025 20:48:55 GMT
Server: Caddy, Caddy

I think the zero length is not from the mercure server but from frankenphp server because when mercure answer at localhost:3000 i'm getting something like this :

root@57729b3b5377:/app# http "http://localhost:3000/.well-known/mercure?topic=chat/user/3/updates&token=eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9.eyJtZXJjdXJlIjp7InN1YnNjcmliZSI6WyIqIl19LCJleHAiOjE3MzY4MDUxNTF9.U1UawedmyLA8i2s74tGSHMbyxSJfjzhjcCnsc7Oh6fs=&heartbeat=1&lastEventID="

HTTP/1.1 401 Unauthorized
Content-Length: 13
Content-Security-Policy: default-src 'self'
Content-Type: text/plain; charset=utf-8
Date: Mon, 13 Jan 2025 20:53:12 GMT
Server: Caddy
X-Content-Type-Options: nosniff
X-Frame-Options: DENY
X-Xss-Protection: 1; mode=block

Unauthorized

Should i have to open external ports in the docker compose config to make mercure directly accessible from the outside ?