From 35cf10e1d62af3aa4ba12e9bc8cdab4ca7f21b57 Mon Sep 17 00:00:00 2001
From: Mike Lang <mikelang3000@gmail.com>
Date: Wed, 2 Nov 2016 13:29:25 -0700
Subject: [PATCH] middleware/errorhandler: Implement Hijacker so it works with
 ws proxy

---
 common/middleware/errorhandler.go | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/common/middleware/errorhandler.go b/common/middleware/errorhandler.go
index fdb539d37..9608c3750 100644
--- a/common/middleware/errorhandler.go
+++ b/common/middleware/errorhandler.go
@@ -1,6 +1,9 @@
 package middleware
 
 import (
+	"bufio"
+	"fmt"
+	"net"
 	"net/http"
 )
 
@@ -78,3 +81,14 @@ func (i *errorInterceptor) Write(data []byte) (int, error) {
 	}
 	return len(data), nil
 }
+
+// errorInterceptor also implements net.Hijacker, to let the downstream Handler
+// hijack the connection. This is needed by the app-mapper's proxy.
+func (i *errorInterceptor) Hijack() (net.Conn, *bufio.ReadWriter, error) {
+	hj, ok := i.originalWriter.(http.Hijacker)
+	if !ok {
+		return nil, nil, fmt.Errorf("error interceptor: can't cast original ResponseWriter to Hijacker")
+	}
+	i.gotCode = true
+	return hj.Hijack()
+}