require proxy auth when not set. fix #712

proxy/http/server.go

@@ -103,7 +103,11 @@ Start:
 
 	if len(s.config.Accounts) > 0 {
 		user, pass, ok := parseBasicAuth(request.Header.Get("Proxy-Authorization"))
-		if !ok || !s.config.HasAccount(user, pass) {
+		if !ok {
+			_, err := conn.Write([]byte("HTTP/1.1 407 Proxy Authentication Required\r\n\r\n"))
+			return err
+		}
+		if !s.config.HasAccount(user, pass) {
 			_, err := conn.Write([]byte("HTTP/1.1 401 UNAUTHORIZED\r\n\r\n"))
 			return err
 		}