将meteor-ios连接到localhost

Question

let Meteor = METCoreDataDDPClient(serverURL: NSURL(string: "wss://127.0.0.1:3000/")!)

或

let Meteor = METCoreDataDDPClient(serverURL: NSURL(string: "http://127.0.0.1:3000/")!)

不连接。如何将其连接到localhost流星实例？