refactor: Restructure project files for better organization, readability, and maintainability

internal/middleware/rate-limit.go

@@ -0,0 +1,95 @@
+package middleware
+
+/*
+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.
+*/
+import (
+	"encoding/json"
+	"github.com/gorilla/mux"
+	"github.com/jkaninda/goma-gateway/pkg/logger"
+	"net/http"
+	"time"
+)
+
+// RateLimitMiddleware limits request based on the number of tokens peer minutes.
+func (rl *TokenRateLimiter) RateLimitMiddleware() mux.MiddlewareFunc {
+	return func(next http.Handler) http.Handler {
+		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+			if !rl.Allow() {
+				// Rate limit exceeded, return a 429 Too Many Requests response
+				w.Header().Set("Content-Type", "application/json")
+				w.WriteHeader(http.StatusTooManyRequests)
+				err := json.NewEncoder(w).Encode(ProxyResponseError{
+					Success: false,
+					Code:    http.StatusTooManyRequests,
+					Message: "Too many requests, API rate limit exceeded. Please try again later.",
+				})
+				if err != nil {
+					return
+				}
+				return
+			}
+
+			// Proceed to the next handler if rate limit is not exceeded
+			next.ServeHTTP(w, r)
+		})
+	}
+}
+
+// RateLimitMiddleware limits request based on the number of requests peer minutes.
+func (rl *RateLimiter) RateLimitMiddleware() mux.MiddlewareFunc {
+	return func(next http.Handler) http.Handler {
+		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+			clientID := getRealIP(r)
+			rl.mu.Lock()
+			client, exists := rl.ClientMap[clientID]
+			if !exists || time.Now().After(client.ExpiresAt) {
+				client = &Client{
+					RequestCount: 0,
+					ExpiresAt:    time.Now().Add(rl.Window),
+				}
+				rl.ClientMap[clientID] = client
+			}
+			client.RequestCount++
+			rl.mu.Unlock()
+
+			if client.RequestCount > rl.Requests {
+				logger.Error("Too many requests from IP: %s %s %s", clientID, r.URL, r.UserAgent())
+				w.Header().Set("Content-Type", "application/json")
+				w.WriteHeader(http.StatusTooManyRequests)
+				err := json.NewEncoder(w).Encode(ProxyResponseError{
+					Success: false,
+					Code:    http.StatusTooManyRequests,
+					Message: "Too many requests, API rate limit exceeded. Please try again later.",
+				})
+				if err != nil {
+					return
+				}
+				return
+			}
+			// Proceed to the next handler if rate limit is not exceeded
+			next.ServeHTTP(w, r)
+		})
+	}
+}
+func getRealIP(r *http.Request) string {
+	if ip := r.Header.Get("X-Real-IP"); ip != "" {
+		return ip
+	}
+	if ip := r.Header.Get("X-Forwarded-For"); ip != "" {
+		return ip
+	}
+	return r.RemoteAddr
+}