Objects are the basic unit for data operations in OSS. Objects are also known as files. OSS does not use a hierarchical structure for objects, but instead uses a flat structure. All elements are stored as objects in buckets. However, OSS supports folders as a concept to group objects and simplify management.
Each object has the following information:
Key: the name of an object. You can query an object based on its name.
Data: the object content that can consist of any number of bytes in length.
Object Meta: the metadata information of an object. Object metadata is a set of key-value pairs that define object attributes such as last modified time and object sizes. You can add user metadata to the object metadata.
By default, the access control list (ACL) of buckets and objects is private. To allow unauthorized users to access these resources, you must grant these users permissions. For example, if you store images and video objects of your website in OSS and you want to allow unauthorized users to access these resources, you must set the ACL of these resources to public read. Otherwise, unauthorized users must send a signed URL to access these resources. For more information, see Authorized third-party download.
Operations on objects: