Initial QSfera import

Server/pkg/middleware/static.go

@@ -0,0 +1,44 @@
+package middleware
+
+import (
+	"net/http"
+	"path"
+	"strings"
+	"time"
+)
+
+// Static is a middleware that serves static assets.
+func Static(root string, fs http.FileSystem, ttl int) func(http.Handler) http.Handler {
+	if !strings.HasSuffix(root, "/") {
+		root = root + "/"
+	}
+
+	static := http.StripPrefix(
+		root,
+		http.FileServer(
+			fs,
+		),
+	)
+
+	// TODO: investigate broken caching - https://github.com/qsfera/server/issues/1094
+	// we don't have a last modification date of the static assets, so we use the service start date
+	//lastModified := time.Now().UTC().Format(http.TimeFormat)
+	//expires := time.Now().Add(time.Second * time.Duration(ttl)).UTC().Format(http.TimeFormat)
+
+	return func(next http.Handler) http.Handler {
+		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+			if strings.HasPrefix(r.URL.Path, path.Join(root, "api")) {
+				next.ServeHTTP(w, r)
+			} else {
+				// TODO: investigate broken caching - https://github.com/qsfera/server/issues/1094
+				//w.Header().Set("Cache-Control", fmt.Sprintf("max-age=%s, must-revalidate", strconv.Itoa(ttl)))
+				//w.Header().Set("Expires", expires)
+				//w.Header().Set("Last-Modified", lastModified)
+				w.Header().Set("Cache-Control", "no-cache, no-store, max-age=0, must-revalidate, value")
+				w.Header().Set("Expires", "Thu, 01 Jan 1970 00:00:00 GMT")
+				w.Header().Set("Last-Modified", time.Now().UTC().Format(http.TimeFormat))
+				static.ServeHTTP(w, r)
+			}
+		})
+	}
+}