client_id : 'Id_of_your_client',

        username : 'your_username',
        password : '@#$%^&',
        grant_type : "password"
    }

client_id : 'Id_of_your_client',

               // client_secret : 'optional depending on the type of client',

                grant_type : "refresh_token" ,

                refresh_token : refresh_token_you_got_earlier

            }