How to Intercept and Refresh Expired JWT Tokens
How to secure application networking paths using automated Axios interceptors to recover expired user sessions seamlessly.
Initialize a Dedicated Axios Instance
Create a custom Axios network client export using 'axios.create()' with base configurations to avoid polluting the global Axios configuration object.
Inject Authorization Headers Automatically
Attach a request interceptor via 'instance.interceptors.request.use()' to automatically inject active access tokens into outgoing HTTP requests.
Establish the Error Interceptor Trap
Attach a response interceptor via 'instance.interceptors.response.use()' to catch incoming API error blocks before they reach user-facing catch blocks.
Detect Token Expiration Codes
Inside the error handler, inspect 'error.response.status'. Look for specific status codes (like '401 Unauthorized') that signal an expired session token.
Check the Retry Tracking Flag
Inspect the custom request configuration property (e.g., 'error.config._retry'). If it is true, reject the promise immediately to prevent endless request loop conditions.
Lock the Active Config Configuration
Flip the structural retry tracking parameter flag 'originalRequest._retry = true' to lock down this specific execution configuration context.
Fire the Refresh Token Endpoint
Dispatch a separate async network call directly to your auth server refresh endpoint, sending secure refresh tokens stored inside HttpOnly cookies.
Update the Core Storage Cache
Save the newly returned access token into your application runtime state memory or client storage blocks.
Replay the Initial Interrupted Request
Update the authorization headers of the original request with the fresh token, and pass it back to the instance client: 'return axiosInstance(originalRequest)'.
Handle Total Session Failure
If the refresh token attempt fails or returns an error, catch the exception, clear local application data caches, and redirect the user back to the login page.
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