Get Blob Tags

مقالة
11/07/2023

The Get Blob Tags operation returns all user-defined tags for the specified blob, version, or snapshot.

Request

You can construct the Get Blob Tags request as follows. We recommend that you use HTTPS. Replace myaccount with the name of your storage account:

GET method request URI	HTTP Version
`https://myaccount.blob.core.windows.net/mycontainer/myblob?comp=tags` `https://myaccount.blob.core.windows.net/mycontainer/myblob?comp=tags&snapshot=<DateTime>` `https://myaccount.blob.core.windows.net/mycontainer/myblob?comp=tags&versionid=<DateTime>`	HTTP/1.1

URI parameters

The following additional parameters may be specified on the request URI.

Parameter	Description
`snapshot`	Optional. The snapshot parameter is an opaque `DateTime` value that, when it's present, specifies the blob snapshot to retrieve. For more information about working with blob snapshots, see Create a snapshot of a blob.
`versionid`	Optional for version 2019-12-12 and later. The `versionid` parameter is an opaque `DateTime` value that, when it's present, specifies the version of the blob to be retrieved.
`timeout`	Optional. The `timeout` parameter is expressed in seconds. For more information, see Set timeouts for Blob Storage operations.

Request headers

The required and optional request headers are described in the following table:

Request header	Description
`Authorization`	Required. Specifies the authorization scheme, account name, and signature. For more information, see Authorize requests to Azure Storage.
`Date` or `x-ms-date`	Required. Specifies the Coordinated Universal Time (UTC) for the request. For more information, see Authorize requests to Azure Storage.
`x-ms-version`	Required for all authorized requests. Optional for anonymous requests. Specifies the version of the operation to use for this request. For more information, see Versioning for the Azure Storage services.
`x-ms-lease-id:<ID>`	Required if the blob has an active lease. To perform this operation on a blob with an active lease, specify the valid lease ID for this header. If a valid lease ID isn't specified on the request, the operation fails with status code 403 (Forbidden).
`x-ms-client-request-id`	Optional. Provides a client-generated, opaque value with a 1-kibibyte (KiB) character limit that's recorded in the logs when logging is configured. We highly recommend that you use this header to correlate client-side activities with requests that the server receives. For more information, see Monitor Azure Blob Storage.

This operation supports the x-ms-if-tags conditional header to get blob tags only if a specified condition is met. For more information, see Specify conditional headers for Blob Storage operations.

Request body

None.

Response

The response includes an HTTP status code, response headers, and a response body.

Status code

A successful operation returns status code 200 (OK).

For information about status codes, see Status and error codes.

Response headers

The response for this operation includes the following headers. The response may also include additional standard HTTP headers. All standard headers conform to the HTTP/1.1 protocol specification.

Response header	Description
`Content-Type`	`application/xml`
`Content-Length`	The size of the returned XML document, in bytes
`x-ms-request-id`	Uniquely identifies the request that was made, and you can use it to troubleshoot the request. For more information, see Troubleshoot API operations.
`x-ms-version`	Indicates the Blob Storage version that's used to execute the request.
`Date`	A UTC date/time value that's generated by the service, which indicates the time when the response was initiated.
`x-ms-client-request-id`	Can be used to troubleshoot requests and their corresponding responses. The value of this header is equal to the value of the `x-ms-client-request-id` header if it's present in the request and the value no more than 1,024 visible ASCII characters. If the `x-ms-client-request-id` header isn't present in the request, this header isn't present in the response.

Response body

Here is the format of the response body:

<?xml version="1.0" encoding="utf-8"?>  
<Tags>  
    <TagSet>  
        <Tag>  
            <Key>tag-name-1</Key>  
            <Value>tag-value-1</Value>  
        </Tag>  
        <Tag>  
            <Key>tag-name-2</Key>  
            <Value>tag-value-2</Value>  
        </Tag>  
    </TagSet>  
</Tags>

The response body is a well-formed UTF-8 XML document that represents all the tags that are stored on the blob.

Authorization

Authorization is required when calling any data access operation in Azure Storage. You can authorize the Get Blob Tags operation as described below.

Azure Storage supports using Microsoft Entra ID to authorize requests to blob data. With Microsoft Entra ID, you can use Azure role-based access control (Azure RBAC) to grant permissions to a security principal. The security principal may be a user, group, application service principal, or Azure managed identity. The security principal is authenticated by Microsoft Entra ID to return an OAuth 2.0 token. The token can then be used to authorize a request against the Blob service.

To learn more about authorization using Microsoft Entra ID, see Authorize access to blobs using Microsoft Entra ID.

Permissions

Listed below are the RBAC action necessary for a Microsoft Entra user, group, or service principal to call the Get Blob Tags operation, and the least privileged built-in Azure RBAC role that includes this action:

Azure RBAC action: Microsoft.Storage/storageAccounts/blobServices/containers/blobs/tags/read
Least privileged built-in role: Storage Blob Data Owner

To learn more about assigning roles using Azure RBAC, see Assign an Azure role for access to blob data.

A shared access signature (SAS) provides secure delegated access to resources in a storage account. With a SAS, you have granular control over how a client can access data. You can specify what resource the client may access, what permissions they have to those resources, and how long the SAS is valid.

The Get Blob Tags operation supports three types of shared access signatures: user delegation SAS, service SAS, and account SAS.

As a security best practice, we recommend that you use Microsoft Entra credentials rather than the storage account key, which can be more easily compromised. If your application design requires shared access signatures, use Microsoft Entra credentials to create a user delegation SAS, when possible.

When Shared Key access is disallowed for the storage account, a service SAS token or an account SAS token will not be permitted on a request to Blob Storage. To learn more, see Understand how disallowing Shared Key affects SAS tokens.

User delegation SAS

A user delegation SAS is secured with Microsoft Entra credentials and also by the permissions specified for the SAS.

Calling the Get Blob Tags operation using a SAS token delegated to a blob resource requires the Tags (t) permission as part of the user delegation SAS token.

To learn more about the user delegation SAS, see Create a user delegation SAS.

Service SAS

A service SAS is secured with the storage account key. A service SAS delegates access to a resource in a single Azure Storage service, such as blob storage.

Calling the Get Blob Tags operation using a SAS token delegated to a blob resource requires the Tags (t) permission as part of the service SAS token.

To learn more about the service SAS, see Create a service SAS.

Account SAS

An account SAS is secured with the storage account key. An account SAS delegates access to resources in one or more of the storage services. All of the operations available via a service or user delegation SAS are also available via an account SAS.

The following table indicates the signed resource type and signed permissions to specify when delegating access:

Operation	Signed service	Signed resource type	Signed permission
Get Blob Tags	Blob (b)	Object (o)	Tags (t)

To learn more about the account SAS, see Create an account SAS.

Remarks

The Get Blob Tags operation is supported in REST API version 2019-12-12 and later.

For accounts with hierarchical namespace enabled, the Get Blob Tags operation is not supported as blob tags are not supported for hierarchical namespace accounts.

The ordering of tags is not guaranteed in the response.

The storage service maintains strong consistency between a blob and its tags, but the secondary index is eventually consistent. Tags might be visible in a response to Get Blob Tags before they're visible to Find Blobs by Tags operations.

Billing

Pricing requests can originate from clients that use Blob Storage APIs, either directly through the Blob Storage REST API, or from an Azure Storage client library. These requests accrue charges per transaction. The type of transaction affects how the account is charged. For example, read transactions accrue to a different billing category than write transactions. The following table shows the billing category for Get Blob Tags requests based on the storage account type:

Operation	Storage account type	Billing category
Get Blob Tags	Premium block blob Standard general-purpose v2	Other operations
Get Blob Tags	Standard general-purpose v1	Read operations

To learn about pricing for the specified billing category, see Azure Blob Storage Pricing.