added media fixes, search, push updates, pwa, metrics. preparing release 1.0

server/internal/platform/ratelimit/ratelimit.go

@@ -0,0 +1,61 @@
+// Package ratelimit provides a simple in-memory fixed-window limiter
+// keyed by client IP, used to protect authentication endpoints.
+package ratelimit
+
+import (
+	"net"
+	"net/http"
+	"strings"
+	"sync"
+	"time"
+)
+
+// Limiter is a fixed-window, per-IP request limiter.
+type Limiter struct {
+	mu     sync.Mutex
+	max    int
+	window time.Duration
+	hits   map[string]*hits
+}
+
+type hits struct {
+	windowStart time.Time
+	count       int
+}
+
+// New returns a limiter allowing max requests per window per IP.
+func New(max int, window time.Duration) *Limiter {
+	return &Limiter{max: max, window: window, hits: make(map[string]*hits)}
+}
+
+// Allow reports whether the request passes the limit, consuming one slot.
+func (l *Limiter) Allow(r *http.Request) bool {
+	ip := ClientIP(r)
+	now := time.Now()
+
+	l.mu.Lock()
+	defer l.mu.Unlock()
+	h := l.hits[ip]
+	if h == nil || now.Sub(h.windowStart) >= l.window {
+		h = &hits{windowStart: now}
+		l.hits[ip] = h
+	}
+	h.count++
+	return h.count <= l.max
+}
+
+// ClientIP extracts the remote address, preferring X-Forwarded-For when
+// running behind a reverse proxy.
+func ClientIP(r *http.Request) string {
+	if fwd := r.Header.Get("X-Forwarded-For"); fwd != "" {
+		if i := strings.IndexByte(fwd, ','); i > 0 {
+			return strings.TrimSpace(fwd[:i])
+		}
+		return strings.TrimSpace(fwd)
+	}
+	host, _, err := net.SplitHostPort(r.RemoteAddr)
+	if err != nil {
+		return r.RemoteAddr
+	}
+	return host
+}