refactor: refactoring of code

Add graceful shutdown server

internal/middlewares/oauth-middleware.go

@@ -0,0 +1,86 @@
+/*
+ * Copyright 2024 Jonas Kaninda
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package middlewares
+
+import (
+	"fmt"
+	"github.com/golang-jwt/jwt"
+	"net/http"
+	"time"
+)
+
+func (oauth Oauth) AuthMiddleware(next http.Handler) http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		oauthConf := oauth2Config(oauth)
+		// Check if the user is authenticated
+		token, err := r.Cookie("goma.oauth")
+		if err != nil {
+			// If no token, redirect to OAuth provider
+			url := oauthConf.AuthCodeURL(oauth.State)
+			http.Redirect(w, r, url, http.StatusTemporaryRedirect)
+			return
+		}
+		ok, err := validateJWT(token.Value, oauth)
+		if err != nil {
+			// If no token, redirect to OAuth provider
+			url := oauthConf.AuthCodeURL(oauth.State)
+			http.Redirect(w, r, url, http.StatusTemporaryRedirect)
+			return
+		}
+		if !ok {
+			// If no token, redirect to OAuth provider
+			url := oauthConf.AuthCodeURL(oauth.State)
+			http.Redirect(w, r, url, http.StatusTemporaryRedirect)
+			return
+		}
+		// Token exists, proceed with request
+		next.ServeHTTP(w, r)
+	})
+}
+
+func validateJWT(signedToken string, oauth Oauth) (bool, error) {
+	// Parse the JWT token and provide the key function
+	token, err := jwt.Parse(signedToken, func(token *jwt.Token) (interface{}, error) {
+		// Ensure the signing method is HMAC and specifically HS256
+		if _, ok := token.Method.(*jwt.SigningMethodHMAC); !ok {
+			return nil, fmt.Errorf("unexpected signing method: %v", token.Header["alg"])
+		}
+		// Return the shared secret key for validation
+		return []byte(oauth.JWTSecret), nil
+	})
+
+	// If there's an error or token is invalid, return false
+	if err != nil || !token.Valid {
+		return false, fmt.Errorf("token is invalid: %v", err)
+	}
+
+	// Check if token claims are valid
+	if claims, ok := token.Claims.(jwt.MapClaims); ok && token.Valid {
+		// Optional: Check token expiration
+		if exp, ok := claims["exp"].(float64); ok {
+			if time.Unix(int64(exp), 0).Before(time.Now()) {
+				return false, fmt.Errorf("token has expired")
+			}
+		}
+
+		// Token is valid and not expired
+		return true, nil
+	}
+
+	return false, fmt.Errorf("token is invalid or missing claims")
+}