What do I do if an error message such as "Request has expired" is displayed when I call an API?

There are two possible causes:

• The signature has expired when you initiate the request.
• Your local system time is out of sync with the local time in your time zone.

For the former case, you are advised to get a new valid request signature before using the API. For the latter case, you need to sync your system time with the time in your time zone.

How do I call an API to delete an object that is not uploaded completely?

First, call the ListMultipartUploads API to list the multipart uploads. Then, call Abort Multipart upload to abort the multipart upload and delete the uploaded parts.

What do I do if a success response is returned for the batch deletion API, while the object failed to be deleted?

Check the object path, which should not start with a /.

How do I modify the storage class for an object using an API?

You can call the PUT Object - Copy API to modify x-cos-storage-class. For more information, please see PUT Object - Copy.

How do I set the COS signature to be permanent?

A timestamp is used to determine whether the COS signature has expired and it cannot be set to permanent. If you use a permanent key to generate the signature and want the signature to be permanent, you can set the timestamp to be a long time (for example, 50 years) after the current time. If your signature is generated using a temporary key, which is valid for only up to 2 hours, your signature will also be valid for only 2 hours.