Implementing a Custom JWT Filter
Build a custom `OncePerRequestFilter` to intercept requests, extract JWTs, and authenticate users.
Why a Custom JWT Filter?
When using JSON Web Tokens (JWTs) for authentication, Spring Security doesn't inherently know how to process them. This is where a custom filter comes in!
A custom JWT filter intercepts incoming requests to:
- Extract the JWT.
- Validate its authenticity and expiration.
- Inform Spring Security about the authenticated user.
The OncePerRequestFilter Base
For our custom JWT filter, we'll extend Spring's OncePerRequestFilter. This base class guarantees that your filter logic runs exactly once per HTTP request, preventing redundant processing.
- It simplifies filter implementation.
- Ensures efficiency for each request.
- It's ideal for authentication logic.