From e1dd5d93264450172cf44608c388416ff72cbb9f Mon Sep 17 00:00:00 2001
From: Marcin Rataj <lidel@lidel.org>
Date: Wed, 15 Apr 2020 13:42:29 +0200
Subject: [PATCH] fix: subdomain redirect for dir CIDs

Closes #7164

License: MIT
Signed-off-by: Marcin Rataj <lidel@lidel.org>


This commit was moved from ipfs/kubo@8290ec11c376d8246a7e592eb4e6472479833077
---
 gateway/core/corehttp/gateway_handler.go | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/gateway/core/corehttp/gateway_handler.go b/gateway/core/corehttp/gateway_handler.go
index d26f21d54..8c7cea134 100644
--- a/gateway/core/corehttp/gateway_handler.go
+++ b/gateway/core/corehttp/gateway_handler.go
@@ -342,6 +342,16 @@ func (i *gatewayHandler) getOrHeadHandler(w http.ResponseWriter, r *http.Request
 		BackLink: backLink,
 		Hash:     hash,
 	}
+
+	// See statusResponseWriter.WriteHeader
+	// and https://github.com/ipfs/go-ipfs/issues/7164
+	// Note: this needs to occur before listingTemplate.Execute otherwise we get
+	// superfluous response.WriteHeader call from prometheus/client_golang
+	if w.Header().Get("Location") != "" {
+		w.WriteHeader(http.StatusMovedPermanently)
+		return
+	}
+
 	err = listingTemplate.Execute(w, tplData)
 	if err != nil {
 		internalWebError(w, err)