From 8f6aa65a10ebce53320ce0a727999e4b970f7c37 Mon Sep 17 00:00:00 2001
From: x3 <sugarpanning@cock.li>
Date: Wed, 28 Feb 2024 00:25:27 +0100
Subject: [PATCH] Return 304 if If-Modified-Since header is present in download

---
 controller/download.go | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/controller/download.go b/controller/download.go
index 528c242..f640224 100644
--- a/controller/download.go
+++ b/controller/download.go
@@ -19,6 +19,15 @@ func Download(w http.ResponseWriter, r *http.Request) {
         http.NotFound(w, r)
         return
     }
+
+    ifModifH := r.Header.Get("If-Modified-Since")
+    if ifModifH != "" {
+        // Is (probably) not modified, send back 304
+        log.Printf("Download (%s): got If-Modified-Since, replying 304\n", id)
+        w.WriteHeader(http.StatusNotModified)
+        return
+    }
+
     d1 := file.Sha1Sum[0:2]
     d2 := file.Sha1Sum[2:4]