fix: extract client IP via net.SplitHostPort consistently

Ultraworked with Sisyphus (https://github.com/code-yeongyu/oh-my-openagent)

Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>

backend/handlers/bookings/reserve.go

@@ -13,6 +13,7 @@ import (
 	"crussell/db"
 	"crussell/handlers/scheduling"
 	"crussell/mw"
+	"net"
 )
 
 // ReserveSlotRequest represents the request body for reserving a slot
@@ -50,22 +51,15 @@ func ReserveSlotHandler(w http.ResponseWriter, r *http.Request) {
 	}
 
 	// b. Extract client IP: check CF-Connecting-IP → X-Real-IP → X-Forwarded-For → RemoteAddr
-	ip := r.Header.Get("CF-Connecting-IP")
-	if ip == "" {
-		ip = r.Header.Get("X-Real-IP")
-	}
-	if ip == "" {
-		ip = r.Header.Get("X-Forwarded-For")
-	}
-	if ip == "" {
-		ip = r.RemoteAddr
-	}
-	// Take first IP if multiple are in X-Forwarded-For
-	if strings.Contains(ip, ",") {
-		ip = strings.Split(strings.TrimSpace(ip), ",")[0]
-	}
+			ip := r.Header.Get("CF-Connecting-IP")
+			if ip == "" {
+				ip, _, _ = net.SplitHostPort(r.RemoteAddr)
+				if ip == "" {
+					ip = r.RemoteAddr
+				}
+			}
 
-	// c. Detect auth: try context first, then parse Bearer token from Authorization header
+			// c. Detect auth: try context first, then parse Bearer token from Authorization header
 	userID, hasUser := r.Context().Value(mw.UserIDKey).(string)
 	hasAuth := hasUser && userID != ""
 

backend/mw/ratelimit.go

@@ -3,6 +3,7 @@ package mw
 import (
 	"net/http"
 	"sync"
+	"net"
 	"time"
 )
 
@@ -79,13 +80,10 @@ func RateLimit(limit int, window time.Duration) func(http.Handler) http.Handler
 			// Get client IP
 			ip := r.Header.Get("CF-Connecting-IP")
 			if ip == "" {
-				ip = r.Header.Get("X-Real-IP")
-			}
-			if ip == "" {
-				ip = r.Header.Get("X-Forwarded-For")
-			}
-			if ip == "" {
-				ip = r.RemoteAddr
+				ip, _, _ = net.SplitHostPort(r.RemoteAddr)
+				if ip == "" {
+					ip = r.RemoteAddr
+				}
 			}
 
 			if !limiter.Allow(ip) {