refactor: implement centralized auth middleware and standardize cross-subdomain session management

api/src/middlewares/auth.js

@@ -0,0 +1,70 @@
+/**
+ * Middleware di autenticazione per API REST.
+ * Supporta tre modalità:
+ *   - x-api-key (service-to-service, INTERNAL_API_KEY)
+ *   - cookie auth_token (utenti loggati dal browser, SSO via .mebboat.it)
+ *   - Authorization: Bearer <jwt>
+ *
+ * Il JWT viene firmato da auth.mebboat.it con JWT_SECRET e verificato localmente.
+ * Il cookie è condiviso tra i sottodomini grazie a domain=.mebboat.it
+ */
+
+const jwt = require('jsonwebtoken');
+
+const SECRET = process.env.JWT_SECRET;
+const INTERNAL_KEY = process.env.INTERNAL_API_KEY;
+
+function extractToken(req) {
+    const header = req.headers.authorization;
+    const bearer = header && header.startsWith('Bearer ') ? header.slice(7) : null;
+    return (req.cookies && req.cookies.auth_token) || bearer || null;
+}
+
+function verifyToken(token) {
+    if (!token || typeof token !== 'string' || token.length > 2048) return null;
+    try {
+        const p = jwt.verify(token, SECRET, { algorithms: ['HS256'] });
+        return {
+            user_id: p.sub,
+            username: p.username,
+            session_id: p.session_id,
+            iat: p.iat,
+            exp: p.exp
+        };
+    } catch {
+        return null;
+    }
+}
+
+/**
+ * Accetta utente loggato (cookie/bearer) o chiamata interna (x-api-key).
+ * Imposta req.user con i dati dell'utente, oppure req.internal = true.
+ */
+function requireAuth(req, res, next) {
+    // 1. Service-to-service
+    const apiKey = req.headers['x-api-key'];
+    if (apiKey && INTERNAL_KEY && apiKey === INTERNAL_KEY) {
+        req.internal = true;
+        return next();
+    }
+
+    // 2. User auth (cookie o Bearer)
+    const user = verifyToken(extractToken(req));
+    if (!user) return res.status(401).json({ error: 'unauthorized' });
+    req.user = user;
+    next();
+}
+
+/**
+ * Solo service-to-service (x-api-key).
+ */
+function requireInternal(req, res, next) {
+    const apiKey = req.headers['x-api-key'];
+    if (!INTERNAL_KEY || !apiKey || apiKey !== INTERNAL_KEY) {
+        return res.status(403).json({ error: 'forbidden' });
+    }
+    req.internal = true;
+    next();
+}
+
+module.exports = { requireAuth, requireInternal, verifyToken, extractToken };