Enable token refresh

auth.ts

@@ -1,13 +1,24 @@
-import NextAuth,{ type DefaultSession } from "next-auth";
+import NextAuth, { type DefaultSession } from "next-auth";
 import Authentik from "next-auth/providers/authentik";
 import { PrismaAdapter } from "@auth/prisma-adapter"
 import { PrismaClient } from "@prisma/client"
+import { JWT } from "next-auth/jwt"
 
 const prisma = new PrismaClient()
 
 declare module "next-auth" {
 	interface Session {
 		access_token: string | undefined;
+		error?: "RefreshAccessTokenError"
+	}
+}
+
+declare module "next-auth/jwt" {
+	interface JWT {
+		access_token: string
+		expires_at: number
+		refresh_token: string
+		error?: "RefreshAccessTokenError"
 	}
 }
 
@@ -20,26 +31,49 @@ export const { handlers, auth, signIn, signOut } = NextAuth({
 		authorization: { params: { scope: 'openid profile email offline_access' } },
 	})],
 	callbacks: {
-    async jwt({token, account}) {
-      if (account) {
-        token = Object.assign({}, token, { access_token: account.access_token });
-      }
-      return token
+		async session({ session, user }) {
+			const [authentikAccount] = await prisma.account.findMany({
+				where: { userId: user.id, provider: "authentik" },
+			})
+
+			if (authentikAccount.expires_at * 1000 < Date.now()) {
+				console.info("refreshing token");
+				try {
+					const response = await fetch(process.env.AUTH_OIDC_TOKEN_URL!, {
+						headers: { "Content-Type": "application/x-www-form-urlencoded" },
+						body: new URLSearchParams({
+							client_id: process.env.AUTH_OIDC_CLIENT_ID!,
+							client_secret: process.env.AUTH_OIDC_CLIENT_SECRET!,
+							grant_type: "refresh_token",
+							refresh_token: authentikAccount.refresh_token,
+						}),
+						method: "POST",
+					})
+
+					const tokens = await response.json()
+
+					if (!response.ok) throw tokens
+					await prisma.account.update({
+						data: {
+							access_token: tokens.access_token,
+							expires_at: Math.floor(Date.now() / 1000 + tokens.expires_in),
+							refresh_token:
+								tokens.refresh_token ?? authentikAccount.refresh_token,
 						},
-    async session({session, user}) {
-      const getToken = await prisma.account.findFirst({
 						where: {
-          userId: user.id,
+							provider_providerAccountId: {
+								provider: "authentik",
+								providerAccountId: authentikAccount.providerAccountId,
 							},
-      });
-
-      let accessToken: string | undefined = undefined;
-      if (getToken) {
-        accessToken = getToken.access_token!;
+						},
+					})
+				} catch (error) {
+					console.error("Error refreshing access token", error)
+					// The error property will be used client-side to handle the refresh token error
+					session.error = "RefreshAccessTokenError"
 				}
-
-      session.access_token = accessToken;
-      return session;
+			}
+			return session
 		}
 	}
 });