feat(errors): improve error handling with thiserror

Cargo.toml

@@ -16,6 +16,7 @@ reqwest = { version = "0.12", default-features = false, features = [
     "rustls-tls",
 ] }
 serde = { version = "1", features = ["derive"] }
+thiserror = "2"
 tokio = { version = "1", default-features = false, features = ["time"] }
 
 [dev-dependencies]

src/axum.rs

@@ -11,6 +11,7 @@ use serde::Deserialize;
 
 use crate::{Decoder, JwtDecoder};
 
+/// A generic struct for holding the claims of a JWT token.
 #[derive(Debug, Deserialize)]
 pub struct Claims<T>(pub T);
 

src/lib.rs

@@ -1,4 +1,17 @@
-//! Provides a thin layer over jsonwebtoken crate to manage remote JWKS and local secret keys.
+//! A Rust library for JWT authentication with support for both local keys and remote JWKS (JSON Web Key Sets).
+//!
+//! This crate provides a flexible JWT authentication system that can:
+//! - Validate tokens using local RSA/HMAC keys
+//! - Automatically fetch and cache remote JWKS endpoints
+//! - Integrate seamlessly with the Axum web framework
+//! - Handle token validation with configurable options
+//!
+//! It builds on top of the `jsonwebtoken` crate to provide higher-level authentication primitives
+//! while maintaining full compatibility with standard JWT implementations.
+//!
+//! # Example
+//!
+//! For a full example, see the [examples](https://github.com/cmackenzie1/axum-jwt-auth/blob/main/examples).
 
 mod axum;
 mod local;
@@ -8,31 +21,27 @@ use std::sync::Arc;
 
 use jsonwebtoken::TokenData;
 use serde::de::DeserializeOwned;
+use thiserror::Error;
 
 pub use crate::axum::{AuthError, Claims, JwtDecoderState};
 pub use crate::local::LocalDecoder;
 pub use crate::remote::{RemoteJwksDecoder, RemoteJwksDecoderBuilder};
 
-#[derive(Debug)]
+#[derive(Debug, thiserror::Error)]
 pub enum Error {
+    #[error("JWT key not found (kid: {0:?})")]
     KeyNotFound(Option<String>),
-    Jwt(jsonwebtoken::errors::Error),
-    Reqwest(reqwest::Error),
+    #[error("JWT error: {0}")]
+    Jwt(#[from] jsonwebtoken::errors::Error),
+    #[error("HTTP request error: {0}")]
+    Reqwest(#[from] reqwest::Error),
+    #[error("JWKS refresh failed: {0}")]
+    JwksRefresh(String),
 }
 
-impl From<reqwest::Error> for Error {
-    fn from(err: reqwest::Error) -> Self {
-        Self::Reqwest(err)
-    }
-}
-
-impl From<jsonwebtoken::errors::Error> for Error {
-    fn from(err: jsonwebtoken::errors::Error) -> Self {
-        Self::Jwt(err)
-    }
-}
-
-/// A trait for decoding JWT tokens.
+/// A generic trait for decoding JWT tokens.
+///
+/// This trait is implemented for both `LocalDecoder` and `RemoteJwksDecoder`
 pub trait JwtDecoder<T>
 where
     T: for<'de> DeserializeOwned,