clarify access token refresh logic a bit

www/app/lib/SessionAutoRefresh.tsx

@@ -9,22 +9,20 @@
 
 import { useEffect } from "react";
 import { useAuth } from "./AuthProvider";
+import { REFRESH_ACCESS_TOKEN_BEFORE } from "./auth";
 
-export function SessionAutoRefresh({
+const REFRESH_BEFORE = REFRESH_ACCESS_TOKEN_BEFORE;
-  children,
+
-  refreshInterval = 5 /* seconds */,
+export function SessionAutoRefresh({ children }) {
-}) {
   const auth = useAuth();
   const accessTokenExpires =
     auth.status === "authenticated" ? auth.accessTokenExpires : null;
-  console.log("authauth", auth);
-  const refreshIntervalMs = refreshInterval * 1000;
 
   useEffect(() => {
     const interval = setInterval(() => {
       if (accessTokenExpires !== null) {
         const timeLeft = accessTokenExpires - Date.now();
-        if (timeLeft < refreshIntervalMs) {
+        if (timeLeft < REFRESH_BEFORE) {
           auth
             .update()
             .then(() => {})
@@ -34,10 +32,10 @@ export function SessionAutoRefresh({
             });
         }
       }
-    }, refreshIntervalMs);
+    }, 5000);
 
     return () => clearInterval(interval);
-  }, [accessTokenExpires, refreshInterval, auth.update]);
+  }, [accessTokenExpires, auth.update]);
 
   return children;
 }

www/app/lib/auth.ts

@@ -1 +1,3 @@
 export const REFRESH_ACCESS_TOKEN_ERROR = "RefreshAccessTokenError" as const;
+// 4 min is 1 min less than default authentic value. here we assume that authentic won't be set to access tokens < 4 min
+export const REFRESH_ACCESS_TOKEN_BEFORE = 4 * 60 * 1000;

www/app/lib/authBackend.ts

@@ -7,15 +7,18 @@ import {
   assertExistsAndNonEmptyString,
   parseMaybeNonEmptyString,
 } from "./utils";
-import { REFRESH_ACCESS_TOKEN_ERROR } from "./auth";
+import {
-
+  REFRESH_ACCESS_TOKEN_BEFORE,
-const PRETIMEOUT = 600;
+  REFRESH_ACCESS_TOKEN_ERROR,
+} from "./auth";
 
+// TODO redis for vercel?
 const tokenCache = new Map<
   string,
   { token: JWTWithAccessToken; timestamp: number }
 >();
-const TOKEN_CACHE_TTL = 60 * 60 * 24 * 30 * 1000; // 30 days in milliseconds
+// REFRESH_ACCESS_TOKEN_BEFORE because refresh is based on access token expiration (imagine we cache it 30 days)
+const TOKEN_CACHE_TTL = REFRESH_ACCESS_TOKEN_BEFORE;
 
 const refreshLocks = new Map<string, Promise<JWTWithAccessToken>>();
 
@@ -49,7 +52,7 @@ export const authOptions: AuthOptions = {
       if (account && user) {
         // called only on first login
         // XXX account.expires_in used in example is not defined for authentik backend, but expires_at is
-        const expiresAtS = assertExists(account.expires_at) - PRETIMEOUT;
+        const expiresAtS = assertExists(account.expires_at);
         const expiresAtMs = expiresAtS * 1000;
         if (!account.access_token) {
           tokenCache.delete(KEY);
@@ -165,8 +168,7 @@ async function refreshAccessToken(token: JWT): Promise<JWTWithAccessToken> {
     return {
       ...token,
       accessToken: refreshedTokens.access_token,
-      accessTokenExpires:
+      accessTokenExpires: Date.now() + refreshedTokens.expires_in * 1000,
-        Date.now() + (refreshedTokens.expires_in - PRETIMEOUT) * 1000,
       refreshToken: refreshedTokens.refresh_token,
     };
   } catch (error) {