adding cache control and etags to responses for static assets + moved handlers/helper upload func

1 files changed, 28 insertions, 0 deletions

diff --git a/system/admin/cache.go b/system/admin/cache.go
new file mode 100644
index 0000000..9962249
--- /dev/null
+++ b/system/admin/cache.go
@@ -0,0 +1,28 @@
+package admin
+
+import (
+	"fmt"
+	"net/http"
+	"strings"
+
+	"github.com/nilslice/cms/system/db"
+)
+
+// CacheControl sets the default cache policy on static asset responses
+func CacheControl(next http.HandlerFunc) http.HandlerFunc {
+	return http.HandlerFunc(func(res http.ResponseWriter, req *http.Request) {
+		etag := db.ConfigCache("etag")
+		policy := fmt.Sprintf("max-age=%d, public, must-revalidate, proxy-revalidate", 60*60*24*30)
+		res.Header().Add("Etag", etag)
+		res.Header().Add("Cache-Control", policy)
+
+		if match := res.Header().Get("If-None-Match"); match != "" {
+			if strings.Contains(match, etag) {
+				res.WriteHeader(http.StatusNotModified)
+				return
+			}
+		}
+
+		next.ServeHTTP(res, req)
+	})
+}