var config = {
  // Replace with your own bucket information
  Bucket: 'examplebucket-1250000000', /* Bucket (required) */
  Region: 'COS_REGION', /* Bucket region (required) */
};
var host = 'ci.' + config.Region + '.myqcloud.com';
var url = 'https://' + host + '/mediabucket';
cos.request({
    Bucket: config.Bucket,
    Region: config.Region,
    Method: 'GET',
    Key: 'mediabucket', /** Fixed value (required) */
    Url: url,
    Query: {
        pageNumber: '1', /** Page number (optional) */
        pageSize: '10', /** Number of entries per page (optional) */
        // regions: 'ap-chengdu', /** Region (optional), such as 'ap-beijing'. To specify multiple values, separate them with commas, such as 'ap-shanghai,ap-beijing'. */
        // bucketNames: 'test-1250000000', /** Bucket name (optional), such as 'test-1250000000'. To specify multiple values, separate them with commas, such as 'test1-1250000000,test2-1250000000'. Exact search is supported. */
        // bucketName: 'test', /** Bucket name prefix for prefix search (optional), such as 'test'. To specify multiple values, separate them with commas, such as 'test1,test2'. */
    }
}, function (err, data) {
    console.log(err || data);
});

function(err, data) { ... }