Imports github.com/aliyun/aliyun-oss-go-sdk/oss github.com/pkg/errors github.com/qiniu/api.v7/auth/qbox github.com/qiniu/api.v7/storage github.com/tencentyun/cos-go-sdk-v5 github.com/upyun/go-sdk/upyun Standard library imports context crypto/md5 encoding/base64 encoding/hex encoding/json io io/ioutil math net/http net/url os path regexp strconv strings time