fix(GRO-2234): bounded sliding expiration for SSO portal sessions (#183)

src/middleware/portalSession.ts

@@ -8,6 +8,32 @@ export interface PortalEnv {
   };
 }
 
+/**
+ * Idle lifetime of an SSO-bridge portal impersonation session. Each authenticated
+ * portal request slides `expiresAt` forward to `now + IDLE_TTL`, so an actively-used
+ * session (e.g. a customer working through the multi-step Book New wizard) never
+ * lapses mid-flow. Matches the staff-console impersonation idle window
+ * (SESSION_TIMEOUT_MINUTES in routes/impersonation.ts). (GRO-2234)
+ */
+export const PORTAL_SESSION_IDLE_TTL_MS = 30 * 60 * 1000;
+
+/**
+ * Absolute cap on a single SSO-bridge portal session's lifetime, measured from
+ * `startedAt`. Sliding can never extend a session beyond this bound, keeping the
+ * impersonation model bounded regardless of how long a customer keeps the tab
+ * active. Deliberately tighter than the previous static 24h mint. (GRO-2234)
+ */
+export const PORTAL_SESSION_MAX_LIFETIME_MS = 8 * 60 * 60 * 1000;
+
+/**
+ * Minimum extension before we issue a sliding-expiration write. Avoids a DB write
+ * on every rapid successive request — at most one slide per minute per session.
+ */
+const PORTAL_SESSION_SLIDE_THRESHOLD_MS = 60 * 1000;
+
+/** Reason marker for sessions minted by the Better Auth -> portal bridge. */
+const SSO_BRIDGE_REASON = "sso-bridge";
+
 /**
  * Validates the X-Impersonation-Session-Id header against the impersonationSessions table.
  * Must be applied to all portal routes.
@@ -16,6 +42,12 @@ export interface PortalEnv {
  * id = sessionId AND status = 'active', and checks session.expiresAt > new Date().
  * Returns 401 if session is invalid/missing/expired.
  * On success, sets c.set("portalClientId", session.clientId) and c.set("portalSessionId", session.id).
+ *
+ * Sliding expiration (GRO-2234): for SSO-bridge sessions, each successful request
+ * extends `expiresAt` to `now + PORTAL_SESSION_IDLE_TTL_MS`, bounded by
+ * `startedAt + PORTAL_SESSION_MAX_LIFETIME_MS`. Staff-initiated impersonation
+ * sessions (any other `reason`) are left untouched, preserving their existing
+ * console-enforced timeout behavior.
  */
 export const validatePortalSession: MiddlewareHandler<PortalEnv> = async (c, next) => {
   const sessionId = c.req.header("X-Impersonation-Session-Id");
@@ -24,16 +56,29 @@ export const validatePortalSession: MiddlewareHandler<PortalEnv> = async (c, nex
   }
 
   const db = getDb();
+  const now = new Date();
   const [session] = await db
     .select()
     .from(impersonationSessions)
     .where(and(eq(impersonationSessions.id, sessionId), eq(impersonationSessions.status, "active")))
     .limit(1);
 
-  if (!session || session.expiresAt <= new Date()) {
+  if (!session || session.expiresAt <= now) {
     return c.json({ error: "Unauthorized" }, 401);
   }
 
+  // Sliding expiration for SSO-bridge portal sessions only (GRO-2234).
+  if (session.reason === SSO_BRIDGE_REASON) {
+    const maxExpiry = session.startedAt.getTime() + PORTAL_SESSION_MAX_LIFETIME_MS;
+    const slidExpiry = Math.min(now.getTime() + PORTAL_SESSION_IDLE_TTL_MS, maxExpiry);
+    if (slidExpiry - session.expiresAt.getTime() >= PORTAL_SESSION_SLIDE_THRESHOLD_MS) {
+      await db
+        .update(impersonationSessions)
+        .set({ expiresAt: new Date(slidExpiry) })
+        .where(eq(impersonationSessions.id, session.id));
+    }
+  }
+
   c.set("portalClientId", session.clientId);
   c.set("portalSessionId", session.id);
   await next();