From 6007bf967bb009622f9ce322e14f17f030736f6b Mon Sep 17 00:00:00 2001
From: Sorin Neacsu <sorin.neacsu@gmail.com>
Date: Tue, 26 Dec 2017 10:05:53 -0800
Subject: [PATCH] rpc: Allow OPTIONS requests without Content-type:
 application/json

---
 rpc/http.go | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/rpc/http.go b/rpc/http.go
index a26559b122..d61b0e470b 100644
--- a/rpc/http.go
+++ b/rpc/http.go
@@ -177,7 +177,7 @@ func validateRequest(r *http.Request) (int, error) {
 		return http.StatusRequestEntityTooLarge, err
 	}
 	mt, _, err := mime.ParseMediaType(r.Header.Get("content-type"))
-	if err != nil || mt != contentType {
+	if r.Method != http.MethodOptions && (err != nil || mt != contentType) {
 		err := fmt.Errorf("invalid content type, only %s is supported", contentType)
 		return http.StatusUnsupportedMediaType, err
 	}