feat: enhance token refresh logic with request queue and improved error handling

src/app/lib/axios.ts

@@ -11,24 +11,42 @@ export const axiosInstance = axios.create({
 	baseURL: process.env.NEXT_PUBLIC_API_URL,
 });
 
+let isRefreshing = false;
+let refreshQueue: Array<(token: string) => void> = [];
+
 axiosInstance.interceptors.request.use(async (config) => {
-	// If the access token is still valid, use it
 	if (tokenExpirationAt && moment().isBefore(tokenExpirationAt)) {
 		config.headers.Authorization = `Bearer ${cachedAccessToken}`;
 		return config;
 	}
 
-	// Otherwise, get a new access token
-	const session = await getSession();
-	if (!session) {
-		throw new Error("User is not authenticated");
+	if (isRefreshing) {
+		// Add the request to the queue
+		return new Promise((resolve) => {
+			refreshQueue.push((token: string) => {
+				config.headers.Authorization = `Bearer ${token}`;
+				resolve(config);
+			});
+		});
 	}
 
-	// Cache the new access token
-	cachedAccessToken = session.accessToken;
-	tokenExpirationAt = moment(session.accessTokenExpires);
+	isRefreshing = true;
 
-	// Use the new access token
-	config.headers.Authorization = `Bearer ${cachedAccessToken}`;
-	return config;
+	try {
+		const session = await getSession();
+		if (!session) {
+			throw new Error("User is not authenticated");
+		}
+
+		cachedAccessToken = session.accessToken;
+		tokenExpirationAt = moment(session.accessTokenExpires);
+
+		// Execute the queue
+		refreshQueue.forEach((cb) => cb(cachedAccessToken!));
+		refreshQueue = [];
+		config.headers.Authorization = `Bearer ${cachedAccessToken}`;
+		return config;
+	} finally {
+		isRefreshing = false;
+	}
 });

src/authOptions.ts

@@ -62,7 +62,11 @@ export const authOptions: AuthOptions = {
 				return token;
 			}
 
-			if (moment().isBefore(moment(token.accessTokenExpires))) {
+			if (
+				moment().isBefore(
+					moment(token.accessTokenExpires).subtract(5, "s"),
+				)
+			) {
 				return token;
 			}
 
@@ -85,41 +89,55 @@ export const authOptions: AuthOptions = {
 	},
 };
 
-const refreshAccessToken = async (token: JWT): Promise<JWT> => {
-	const response = await axios.post<{
-		access_token: string;
-		expires_in: number;
-		refresh_token: string;
-		error_description?: string;
-	}>(
-		process.env.OAUTH_TOKEN_URL,
-		{
-			grant_type: "refresh_token",
-			refresh_token: token.refreshToken,
-			client_id: process.env.OAUTH_CLIENT_ID,
-			client_secret: process.env.OAUTH_CLIENT_SECRET,
-		},
-		{
-			headers: {
-				"Content-Type": "application/x-www-form-urlencoded",
-			},
-		},
-	);
+let isRefreshing = false;
+let refreshPromise: Promise<JWT> | null = null;
 
-	if (response.status != 200) {
-		throw new Error(
-			response.data.error_description || "Failed to refresh access token",
-		);
+const refreshAccessToken = async (token: JWT): Promise<JWT> => {
+	// If another request is already refreshing the token, wait for it to finish
+	if (isRefreshing) {
+		return refreshPromise!;
 	}
 
-	return {
-		...token,
-		accessToken: response.data.access_token,
-		accessTokenExpires: moment()
-			.add(response.data.expires_in, "seconds")
-			.subtract(5, "s"),
-		refreshToken: response.data.refresh_token,
-	};
+	isRefreshing = true;
+	refreshPromise = (async () => {
+		try {
+			const response = await axios.post<{
+				access_token: string;
+				expires_in: number;
+				refresh_token: string;
+				error_description?: string;
+			}>(
+				process.env.OAUTH_TOKEN_URL!,
+				{
+					grant_type: "refresh_token",
+					refresh_token: token.refreshToken,
+					client_id: process.env.OAUTH_CLIENT_ID,
+					client_secret: process.env.OAUTH_CLIENT_SECRET,
+				},
+				{
+					headers: {
+						"Content-Type": "application/x-www-form-urlencoded",
+					},
+				},
+			);
+
+			if (response.status !== 200) throw response.data;
+
+			return {
+				...token,
+				accessToken: response.data.access_token,
+				accessTokenExpires: moment()
+					.add(response.data.expires_in, "seconds")
+					.subtract(5, "s"),
+				refreshToken: response.data.refresh_token,
+			};
+		} finally {
+			isRefreshing = false;
+			refreshPromise = null;
+		}
+	})();
+
+	return refreshPromise;
 };
 
 export const getSession = cache(() => getServerSession());