Add statistic api

server/utils/cache.go

@@ -0,0 +1,29 @@
+package utils
+
+import "time"
+
+type MemValueCache[T any] struct {
+	value    T
+	duration time.Duration
+	expiry   time.Time
+}
+
+func NewMemValueCache[T any](duration time.Duration) *MemValueCache[T] {
+	return &MemValueCache[T]{
+		duration: duration,
+	}
+}
+
+func (c *MemValueCache[T]) Get(fetchFunc func() (T, error)) (T, error) {
+	var zero T
+	if time.Now().Before(c.expiry) {
+		return c.value, nil
+	}
+	v, err := fetchFunc()
+	if err != nil {
+		return zero, err
+	}
+	c.value = v
+	c.expiry = time.Now().Add(c.duration)
+	return v, nil
+}