Object

Objects reside in buckets and contain user data in the format you uploaded it.

An object ID is a string key.

Along with the object, Object Storage stores user and system metadata.

Object Storage allows you to store objects in storages of various classes depending on how long you want to store your objects and how often you access them. For more information, see Storage class.

Object Storage supports the following operations with objects:

• Uploading an object to a storage.
• Downloading an object from a storage.
• Copying an object within a storage, e.g., from one bucket to another.
• Deleting an object.
• Partial object update in a storage.

You can also combine these operations using the tools.

You can configure lifecycles for bucket objects.

Object Storage limits the size of objects and their metadata. For more information, see Quotas and limits in Object Storage.

KeyKey

A key is an ID of an object in a bucket.

Objects are stored in a flat structure, although GUI-based tools allow you to use Object Storage as a hierarchical file system. Hierarchical view is possible because you can write keys as paths in a file system, e.g., top_level_prefix/subprefix/text_data.txt. In the Yandex Cloud management console, prefixes are called directories.

A key must:

• Be UTF-8 encoded.
• Be less than 1024 bytes in size.
• Not contain these characters: : * ? " < > | !.

The following characters are safe to use in a key: [a-zA-Z0-9], -, _, /, \. Other characters may cause various issues in Object Storage.

DirectoryDirectory

There are no directories in Object Storage, but GUI-based file management clients, such as CyberDuck and the Object Storage interface in the Yandex Cloud management console, can emulate them. Such an emulated directory is a zero-size object. Its key is included as a prefix in the keys of other objects. For example, an object with the x key and zero size is a directory in the management console, while an object with the x/y.txt key is the y.txt object located in the x directory.

Each tool manages objects and directories according to its own logic, which is described in the respective documentation.

Object URLObject URL

You can specify a link to a bucket object in one of the following formats:

• For a bucket with public access:
  • http(s)://<bucket>.storage.yandexcloud.net/<key>
  • https://storage.yandexcloud.net/<bucket>/<key>
• For a bucket with restricted access:
  • http(s)://<bucket>.storage.yandexcloud.net/<key>?<parameters>
  • https://storage.yandexcloud.net/<bucket>/<key>?<parameters>

Where:

• <bucket>: Bucket name.
• <key>: Key (file path).
• <parameters>: Additional parameters for accessing a bucket with restricted access, e.g., a signature and validity period.

You can get files from a publicly available bucket using a public link via both HTTP and HTTPS even if no website hosting is configured for the bucket. In this case, a cloud-level certificate from GlobalSign will be used for HTTPS access.

For a bucket with restricted access, the service generates a temporary pre-signed URL that allows you to download an object even from a bucket with restricted access. You can read more about pre-signed URLs, their generation, and their use here.

MetadataMetadata

Metadata is stored with the object as key-value pairs. This can be either system or user metadata.

You can use the metadata to search for objects.

System metadataSystem metadata

System metadata is defined by Object Storage.

Key	Description
Date	Date and time the request to upload an object to Object Storage was sent.
Content-Length	Object size in bytes.
Last-Modified	Date the object was created or last modified.
Content-MD5	Object MD5 hash value, Base64-encoded.
Cache-Control	Value of the Cache-Control HTTP header provided by the client when saving the object to the bucket. Object Storage later returns this header to clients when responding to a request for an object or its metadata. For example, the Cache-Control: max-age=200 header means the object expires 200 seconds after the client receives it. You can read more about it in RFC 7234.
Expires	Value of the Expires HTTP header provided by the client when saving the object to the bucket. Object Storage later returns this header to clients when responding to a request for an object or its metadata. For example, the Expires: Thu, 15 Apr 2020 20:00:00 GMT header means the object expires at 20:00:00 GMT on April 15, 2020. You can read more about it in RFC 7234.

User-defined metadataUser-defined metadata

When uploading an object to Object Storage, you can provide its metadata as key-value pairs.

In an Amazon S3-compatible HTTP API, metadata is provided as HTTP headers. The header name must start with X-Amz-Meta-. For an object request via the HTTP API, Object Storage returns metadata as HTTP headers with the same prefix.

Metadata keys must consist of ASCII characters only. The headers will be transformed as follows: X-Amz-Meta-foo-bar_baz → X-Amz-Meta-Foo-Bar_baz, where Foo-Bar_baz is the key of the metadata that will be saved with the object.

For more information, see Managing object custom metadata.

Use casesUse cases

• Getting object query statistics using S3 Select
• Getting statistics on queries to Object Storage objects using Yandex Query
• Automatically copying objects from one Object Storage bucket to another

See alsoSee also

• Access management methods in Object Storage: Overview