Do #74 (comment)

rc.go

@@ -8,6 +8,7 @@ import (
 	"net/http"
 	"net/http/httptest"
 	"os"
+	"strings"
 	"syscall"
 	"time"
 
@@ -88,7 +89,7 @@ func newCacheMw(c Cacher, opts ...Option) *cacheMw {
 func (m *cacheMw) Handler(next http.Handler) http.Handler {
 	return http.HandlerFunc(func(w http.ResponseWriter, req *http.Request) {
 		// rc does not support websocket.
-		if req.Header.Get("Connection") == "Upgrade" && req.Header.Get("Upgrade") == "websocket" {
+		if strings.ToLower(req.Header.Get("Connection")) == "upgrade" && strings.ToLower(req.Header.Get("Upgrade")) == "websocket" {
 			next.ServeHTTP(w, req)
 			return
 		}

rc_test.go

@@ -54,8 +54,8 @@ func TestRC(t *testing.T) {
 		}, 1},
 		{"does not support websocket", testutil.NewAllCache(t), []*http.Request{
 			{Method: http.MethodGet, Header: http.Header{"Connection": []string{"Upgrade"}, "Upgrade": []string{"websocket"}}, URL: testutil.MustParseURL("http://example.com/1")},
-			{Method: http.MethodGet, Header: http.Header{"Connection": []string{"Upgrade"}, "Upgrade": []string{"websocket"}}, URL: testutil.MustParseURL("http://example.com/1")},
-			{Method: http.MethodGet, Header: http.Header{"Connection": []string{"Upgrade"}, "Upgrade": []string{"websocket"}}, URL: testutil.MustParseURL("http://example.com/1")},
+			{Method: http.MethodGet, Header: http.Header{"Connection": []string{"Upgrade"}, "UPGRADE": []string{"websocket"}}, URL: testutil.MustParseURL("http://example.com/1")},
+			{Method: http.MethodGet, Header: http.Header{"Connection": []string{"Upgrade"}, "Upgrade": []string{"WEBSOCKET"}}, URL: testutil.MustParseURL("http://example.com/1")},
 		}, []*http.Response{
 			{StatusCode: http.StatusOK, Header: http.Header{"Cache-Control": []string{"max-age=60"}, "Content-Type": []string{"application/json"}}, Body: testutil.NewBody(`{"count":1}`)},
 			{StatusCode: http.StatusOK, Header: http.Header{"Cache-Control": []string{"max-age=60"}, "Content-Type": []string{"application/json"}}, Body: testutil.NewBody(`{"count":2}`)},