1，创建一个从NSObject和PFUserAuthenticationDelegate扩展的类。

class AuthDelegate:NSObject, PFUserAuthenticationDelegate {
    func restoreAuthenticationWithAuthData(authData: [String : String]?) -> Bool {
        return true
    }
}

2，注册该认证代表

// parmeter 'forAuthType' is the name of file defined in 
// https://github.com/parse-community/parse-server/blob/master/src/Adapters/Auth/index.js
// such as: google, github, linkedin ......
PFUser.registerAuthenticationDelegate(AuthDelegate(), forAuthType: "google")

3，使用PFUser.logInWithAuthTypeInBackground方法将用户信息存储到_User

// for google oauth, authData format will be
// ["id":"PUT_USER_ID_HERE","accesstoken":"PUT_TOKEN_HERE"]
PFUser.logInWithAuthType(inBackground: "google", authData:[.....])

4，您将看到在_User中创建一条记录，其中只有objectId和authData