From 7fd9eccc386c8a6ff7f2b83f6ef4b58e4d8026be Mon Sep 17 00:00:00 2001
From: Peter Waller <p@pwaller.net>
Date: Tue, 30 Dec 2014 12:19:43 +0000
Subject: [PATCH] Implement ReverseProxy request cancellation

Fixes #8406
---
 src/net/http/httputil/reverseproxy.go | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/src/net/http/httputil/reverseproxy.go b/src/net/http/httputil/reverseproxy.go
index ab463701803bd..524e28011ff64 100644
--- a/src/net/http/httputil/reverseproxy.go
+++ b/src/net/http/httputil/reverseproxy.go
@@ -109,6 +109,21 @@ func (p *ReverseProxy) ServeHTTP(rw http.ResponseWriter, req *http.Request) {
 	outreq := new(http.Request)
 	*outreq = *req // includes shallow copies of maps, but okay
 
+	go func() {
+		cn, ok := rw.(http.CloseNotifier)
+		if !ok {
+			// In this case, rw may have been wrapped and there is nothing
+			// that can be done.
+			return
+		}
+		<-cn.CloseNotify()
+		t, ok := transport.(*http.Transport)
+		if !ok {
+			return
+		}
+		t.CancelRequest(outreq)
+	}()
+
 	p.Director(outreq)
 	outreq.Proto = "HTTP/1.1"
 	outreq.ProtoMajor = 1