Added cache control middleware.

middleware/cache.go

@@ -0,0 +1,20 @@
+package middleware
+
+import (
+	"fmt"
+
+	"github.com/labstack/echo/v4"
+)
+
+func CacheControl(maxAge int) echo.MiddlewareFunc {
+	return func(next echo.HandlerFunc) echo.HandlerFunc {
+		return func(c echo.Context) error {
+			v := "no-cache, no-store"
+			if maxAge > 0 {
+				v = fmt.Sprintf("public, max-age=%d", maxAge)
+			}
+			c.Response().Header().Set("Cache-Control", v)
+			return next(c)
+		}
+	}
+}