Add charset to UTF-8 for content type headers

server.go

@@ -98,7 +98,7 @@ func (s *Server) sendResponse(resp http.ResponseWriter, ip *IP, responseType res
 	s.logger.Printf("Request from %s %s\n", ip.version, ip)
 
 	var body []byte
-	var contentType = "text/plain"
+	var contentType = "text/plain; charset=utf-8"
 	var err error
 
 	switch responseType {
@@ -108,7 +108,7 @@ func (s *Server) sendResponse(resp http.ResponseWriter, ip *IP, responseType res
 		if marshalErr != nil {
 			err = errors.Wrap(marshalErr, "could not marshal json")
 		}
-		contentType = "application/json"
+		contentType = "application/json; charset=utf-8"
 		body = jsonBody
 
 	case htmlResponse:
@@ -117,7 +117,7 @@ func (s *Server) sendResponse(resp http.ResponseWriter, ip *IP, responseType res
 		if exeErr != nil {
 			err = errors.Wrap(exeErr, "could not get html")
 		}
-		contentType = "text/html"
+		contentType = "text/html; charset=utf-8"
 		body = buffer.Bytes()
 
 	default: