Corrige la redirection login derrière un reverse proxy (AUTH_URL)

La redirection vers /login utilisait http://localhost:8413 (ancienne valeur par
défaut d'AUTH_URL). On retire ce défaut localhost : AUTH_URL prend la valeur
fournie (ex. https://pleinr.ffnancy.fr) et pilote la redirection. Ajout de
AUTH_TRUST_HOST=true (confiance aux en-têtes X-Forwarded-*) et l'entrypoint
supprime AUTH_URL si vide. Vérifié : la redirection pointe vers le domaine public.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01XwfhYHzC9hQWPDnQ2p53GL

.env.example

@@ -16,8 +16,10 @@ POSTGRES_DB=pleinr
 # persists one automatically. To set it yourself: openssl rand -base64 32
 AUTH_SECRET=
 # Public URL of the app (used by Auth.js for callbacks).
-# With docker-compose the app is published on host port 8413 by default.
+# Leave EMPTY behind a reverse proxy (Nginx Proxy Manager, Traefik…): Auth.js
-AUTH_URL=http://localhost:8413
+# auto-detects it from the Host / X-Forwarded-Proto headers (trustHost).
+# Set it only to force a value, e.g. https://pleinr.ffnancy.fr
+AUTH_URL=
 
 # ---- First admin user (created by the seed script) ----
 SEED_ADMIN_EMAIL=admin@plein-r.fr

docker-compose.yml

@@ -41,7 +41,12 @@ services:
       # Optional: if left empty, the container generates and persists one
       # automatically (see docker-entrypoint.sh + the app-data volume).
       AUTH_SECRET: ${AUTH_SECRET:-}
-      AUTH_URL: ${AUTH_URL:-http://localhost:8413}
+      # IMPORTANT behind a reverse proxy: set AUTH_URL to your public URL so the
+      # login redirect points to the right host, e.g.
+      #   AUTH_URL=https://pleinr.ffnancy.fr
+      AUTH_URL: ${AUTH_URL:-}
+      # Lets Auth.js trust the X-Forwarded-* headers from the proxy.
+      AUTH_TRUST_HOST: "true"
       SEED_ON_START: ${SEED_ON_START:-true}
       SEED_ADMIN_EMAIL: ${SEED_ADMIN_EMAIL:-admin@plein-r.fr}
       SEED_ADMIN_PASSWORD: ${SEED_ADMIN_PASSWORD:-changeme123}

docker-entrypoint.sh

@@ -16,6 +16,12 @@ if [ -z "$AUTH_SECRET" ]; then
   export AUTH_SECRET
 fi
 
+# If AUTH_URL is empty, unset it so Auth.js derives the public URL from the
+# reverse-proxy headers (trustHost) instead of falling back to a hardcoded host.
+if [ -z "$AUTH_URL" ]; then
+  unset AUTH_URL
+fi
+
 echo "→ Applying database migrations…"
 node dist/migrate.cjs
 

src/middleware.ts

@@ -2,6 +2,8 @@ import NextAuth from "next-auth";
 import { authConfig } from "@/auth.config";
 
 // Edge-safe auth instance (no providers / db) used only to gate routes.
+// The redirect target is derived from AUTH_URL (set it to your public URL when
+// running behind a reverse proxy, e.g. AUTH_URL=https://pleinr.ffnancy.fr).
 export const { auth: middleware } = NextAuth(authConfig);
 
 export default middleware;