add TokenError

jwt.go

@@ -118,6 +118,16 @@ var ErrJWTMissing = echo.NewHTTPError(http.StatusUnauthorized, "missing or malfo
 // ErrJWTInvalid denotes an error raised when JWT token value is invalid or expired
 var ErrJWTInvalid = echo.NewHTTPError(http.StatusUnauthorized, "invalid or expired jwt")
 
+// TokenError is used to return error with error occurred JWT token when processing JWT token
+type TokenError struct {
+	Token *jwt.Token
+	Err   error
+}
+
+func (e *TokenError) Error() string { return e.Err.Error() }
+
+func (e *TokenError) Unwrap() error { return e.Err }
+
 // JWT returns a JSON Web Token (JWT) auth middleware.
 //
 // For valid token, it sets the user in context and calls next handler.
@@ -233,9 +243,12 @@ func (config Config) ToMiddleware() (echo.MiddlewareFunc, error) {
 	}, nil
 }
 
+// defaultKeyFunc creates JWTGo implementation for KeyFunc.
+//
+// error returns TokenError.
 func (config Config) defaultKeyFunc(token *jwt.Token) (interface{}, error) {
 	if token.Method.Alg() != config.SigningMethod {
-		return nil, fmt.Errorf("unexpected jwt signing method=%v", token.Header["alg"])
+		return nil, &TokenError{Token: token, Err: fmt.Errorf("unexpected jwt signing method=%v", token.Header["alg"])}
 	}
 	if len(config.SigningKeys) == 0 {
 		return config.SigningKey, nil
@@ -246,17 +259,19 @@ func (config Config) defaultKeyFunc(token *jwt.Token) (interface{}, error) {
 			return key, nil
 		}
 	}
-	return nil, fmt.Errorf("unexpected jwt key id=%v", token.Header["kid"])
+	return nil, &TokenError{Token: token, Err: fmt.Errorf("unexpected jwt key id=%v", token.Header["kid"])}
 }
 
-// defaultParseTokenFunc creates JWTGo implementation for ParseTokenFunc
+// defaultParseTokenFunc creates JWTGo implementation for ParseTokenFunc.
+//
+// error returns TokenError.
 func (config Config) defaultParseTokenFunc(c echo.Context, auth string) (interface{}, error) {
 	token, err := jwt.ParseWithClaims(auth, config.NewClaimsFunc(c), config.KeyFunc)
 	if err != nil {
-		return nil, err
+		return nil, &TokenError{Token: token, Err: err}
 	}
 	if !token.Valid {
-		return nil, errors.New("invalid token")
+		return nil, &TokenError{Token: token, Err: errors.New("invalid token")}
 	}
 	return token, nil
 }