From 2e79b5a5e78003ccd0f27fc896f99465423f4761 Mon Sep 17 00:00:00 2001
From: Chris Lajoie <chris@ettaviation.com>
Date: Mon, 27 Jan 2020 09:24:40 -0700
Subject: [PATCH] Fix infinite buffering of SSE responses when gzip is enabled
 (#739)

---
 proxy/gzip/gzip_handler.go | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/proxy/gzip/gzip_handler.go b/proxy/gzip/gzip_handler.go
index 9cdf70d10..f59f805b6 100644
--- a/proxy/gzip/gzip_handler.go
+++ b/proxy/gzip/gzip_handler.go
@@ -21,6 +21,7 @@ import (
 
 const (
 	headerVary            = "Vary"
+	headerAccept          = "Accept"
 	headerAcceptEncoding  = "Accept-Encoding"
 	headerContentEncoding = "Content-Encoding"
 	headerContentType     = "Content-Type"
@@ -28,6 +29,8 @@ const (
 	encodingGzip          = "gzip"
 )
 
+var blacklistedAcceptContentTypes = []string{"text/event-stream"}
+
 var gzipWriterPool = sync.Pool{
 	New: func() interface{} { return gzip.NewWriter(nil) },
 }
@@ -110,5 +113,11 @@ func isCompressable(header http.Header, contentTypes *regexp.Regexp) bool {
 }
 
 func acceptsGzip(r *http.Request) bool {
+	accept := r.Header.Get(headerAccept)
+	for _, contentType := range blacklistedAcceptContentTypes {
+		if strings.Contains(accept, contentType) {
+			return false
+		}
+	}
 	return strings.Contains(r.Header.Get(headerAcceptEncoding), encodingGzip)
 }