Fix proxy redirect losing /api/ prefix and port on trailing-slash redirects

claude · claude · commit 35eff1cedfa9 · 2026-02-08T18:31:44.000Z
FastAPI issues 307 redirects to add trailing slashes (e.g. /editor/create_flow → /editor/create_flow/). When proxy_set_header Host $host was used, the redirect Location header used the external hostname without port (http://192.168.50.176/editor/create_flow/), bypassing both the /api/ prefix and the correct port (8080). Fix by removing the Host override so nginx uses the default $proxy_host (flowfile-core:63578). Now the backend's redirect points to the internal host, and nginx's built-in proxy_redirect default correctly rewrites it to http://<external-host>:8080/api/editor/create_flow/. Also remove premature WebSocket headers (Connection: "upgrade" was being sent on all requests) and add X-Forwarded-Host so the backend can access the original host if needed. https://claude.ai/code/session_01HtZJr4MnVSYw8MGuqgKiTq
diff --git a/flowfile_frontend/nginx.conf b/flowfile_frontend/nginx.conf
@@ -9,21 +9,24 @@ server {
     location /api/ {
         proxy_pass http://flowfile-core:63578/;
         proxy_http_version 1.1;
-        proxy_set_header Host $host;
+
+        # Do NOT override Host — let nginx use the default $proxy_host
+        # (flowfile-core:63578). This is critical because FastAPI may issue
+        # trailing-slash redirects using the Host header. With the default
+        # $proxy_host, the redirect Location points to the internal host,
+        # and nginx's built-in proxy_redirect (default) correctly rewrites
+        # it back to the external URL with the /api/ prefix and correct port.
         proxy_set_header X-Real-IP $remote_addr;
         proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
         proxy_set_header X-Forwarded-Proto $scheme;
+        proxy_set_header X-Forwarded-Host $http_host;
         proxy_read_timeout 300s;
         proxy_send_timeout 300s;
 
         # SSE support for log streaming
         proxy_buffering off;
         proxy_cache off;
 
-        # WebSocket support (for future real-time features)
-        proxy_set_header Upgrade $http_upgrade;
-        proxy_set_header Connection "upgrade";
-
         # Allow large file uploads
         client_max_body_size 500M;
     }
