feat: add rate limiting to feed endpoint and update route paths

- Implement per-client rate limiting (5 requests per 3 seconds)
- Change /channel/:id routes to /feed/:id for consistency
- Add data/ to .gitignore
- Include RateLimit middleware on GET /feed/:id endpoint

.gitignore

@@ -1,3 +1,4 @@
 .env
 .vscode/launch.json
-main
+main
+data/

internal/server/http.go

@@ -44,13 +44,12 @@ func RegisterRoutes(params RouterParams) {
 				})
 			})
 
-			// params.GinEngine.GET("/channel/:id/json", params.ChannelHandler.GetMessagesJson)
-			params.GinEngine.GET("/channel/:id", params.ChannelHandler.GetMessagesRSS)
+			// params.GinEngine.GET("/feed/:id/json", params.ChannelHandler.GetMessagesJson)
+			params.GinEngine.GET("/feed/:id", RateLimit(), params.ChannelHandler.GetMessagesRSS)
 
 			// TODO: improve accurecy in rss channel fields
 			// TODO: add ui with templates under /setup with fetch
 			// TODO: add gin level cache (look for higher limit)
-			// TODO: add gin level ip ratelimit
 			// TODO: image endpoint + hash and expiry
 			authStatCtx, cancel := context.WithTimeout(context.Background(), config.AuthStatusTimeout)
 			defer cancel()

internal/server/ratelimiter.go

@@ -0,0 +1,46 @@
+package server
+
+import (
+	"sync"
+	"time"
+
+	"github.com/gin-gonic/gin"
+	"golang.org/x/time/rate"
+)
+
+type ClientLimiter struct {
+	limiter  *rate.Limiter
+	lastSeen time.Time
+}
+
+var clients = map[string]*ClientLimiter{}
+var mu sync.Mutex
+
+func getLimiter(ip string) *rate.Limiter {
+	mu.Lock()
+	defer mu.Unlock()
+
+	if c, ok := clients[ip]; ok {
+		c.lastSeen = time.Now()
+		return c.limiter
+	}
+
+	limiter := rate.NewLimiter(rate.Every(time.Second * 3), 5) // TODO: get from config
+	clients[ip] = &ClientLimiter{limiter: limiter, lastSeen: time.Now()}
+
+	return limiter
+}
+
+func RateLimit() gin.HandlerFunc {
+	return func(c *gin.Context) {
+		ip := c.ClientIP()
+
+		limiter := getLimiter(ip)
+
+		if !limiter.Allow() {
+			c.AbortWithStatusJSON(429, gin.H{"error": "Slow down pls"})
+			return
+		}
+		c.Next()
+	}
+}