From 4a05d131f0413254f84a0f42f7161f6db9ffddac Mon Sep 17 00:00:00 2001
From: Florian Reiterer <fr@insidernavigation.com>
Date: Tue, 2 Feb 2016 16:25:02 +0100
Subject: [PATCH] Cancel context when HTTP connection is closed

---
 protoc-gen-grpc-gateway/gengateway/template.go | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/protoc-gen-grpc-gateway/gengateway/template.go b/protoc-gen-grpc-gateway/gengateway/template.go
index c7d3e8d91bf..57bd5210ac1 100644
--- a/protoc-gen-grpc-gateway/gengateway/template.go
+++ b/protoc-gen-grpc-gateway/gengateway/template.go
@@ -245,6 +245,14 @@ func Register{{$svc.GetName}}Handler(ctx context.Context, mux *runtime.ServeMux,
 	{{range $m := $svc.Methods}}
 	{{range $b := $m.Bindings}}
 	mux.Handle({{$b.HTTPMethod | printf "%q"}}, pattern_{{$svc.GetName}}_{{$m.GetName}}_{{$b.Index}}, func(w http.ResponseWriter, req *http.Request, pathParams map[string]string) {
+		ctx, cancel := context.WithCancel(ctx)
+		closeNotifier, ok := w.(http.CloseNotifier)
+		if ok {
+			go func() {
+				<-closeNotifier.CloseNotify()
+				cancel()
+			}()
+		}
 		resp, err := request_{{$svc.GetName}}_{{$m.GetName}}_{{$b.Index}}(runtime.AnnotateContext(ctx, req), client, req, pathParams)
 		if err != nil {
 			runtime.HTTPError(ctx, w, req, err)