From cea68afa2e8d78fd64ac476eeedc3e7b2ffc4d9d Mon Sep 17 00:00:00 2001
From: Matt Bell <mappum@gmail.com>
Date: Wed, 28 Jan 2015 03:42:07 -0800
Subject: [PATCH] core/corehttp: Handle Etag for caching

---
 core/corehttp/gateway_handler.go | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/core/corehttp/gateway_handler.go b/core/corehttp/gateway_handler.go
index 85bb90bf4..37fe1d5c5 100644
--- a/core/corehttp/gateway_handler.go
+++ b/core/corehttp/gateway_handler.go
@@ -129,8 +129,14 @@ func (i *gatewayHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
+	etag := path.Base(p)
+	if r.Header.Get("If-None-Match") == etag {
+		w.WriteHeader(http.StatusNotModified)
+		return
+	}
+
+	w.Header().Set("Etag", etag)
 	w.Header().Set("X-IPFS-Path", p)
-	w.Header().Set("Etag", path.Base(p))
 	w.Header().Set("Cache-Control", "public, max-age=29030400")
 
 	dr, err := i.NewDagReader(nd)