Copy Blob From URL

Article
11/07/2023

The Copy Blob From URL operation copies a blob to a destination within the storage account synchronously for source blob sizes up to 256 mebibytes (MiB). This API is available starting in version 2018-03-28.

The source for a Copy Blob From URL operation can be any committed block blob in any Azure storage account that's either public or authorized with a shared access signature.

Request

You can construct the Copy Blob From URL request as follows. We recommend HTTPS. Replace myaccount with the name of your storage account, mycontainer with the name of your container, and myblob with the name of your destination blob.

PUT method request URI	HTTP version
`https://myaccount.blob.core.windows.net/mycontainer/myblob`	HTTP/1.1

URI for the emulated storage service

When you're making a request against the emulated storage service, specify the emulator host name and Azure Blob Storage port as 127.0.0.1:10000, followed by the name of the emulated storage account:

PUT method request URI	HTTP version
`http://127.0.0.1:10000/devstoreaccount1/mycontainer/myblob`	HTTP/1.1

For more information, see Use the Azurite emulator for local Azure Storage development.

URI parameters

You can specify the following additional parameters on the request URI:

Parameter	Description
`timeout`	Optional. The `timeout` parameter is expressed in seconds. For more information, see Set timeouts for Blob Storage operations.

Request headers

The following table describes required and optional request headers:

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. For more information, see Versioning for the Azure Storage services.
`x-ms-meta-name:value`	Optional. Specifies a user-defined name/value pair associated with the blob. If no name/value pairs are specified, the operation will copy the metadata from the source blob or file to the destination blob. If one or more name/value pairs are specified, the destination blob is created with the specified metadata, and metadata is not copied from the source blob or file. Beginning with version 2009-09-19, metadata names must adhere to the naming rules for C# identifiers. For more information, see Naming and referencing containers, blobs, and metadata.
`x-ms-encryption-scope`	Optional. Indicates the encryption scope for encrypting the request contents. This header is supported in version 2020-12-06 and later.
`x-ms-tags`	Optional. Sets query-string-encoded tags on the blob. Tags are not copied from the copy source. For more information, see Remarks. Supported in version 2019-12-12 and later.
`x-ms-copy-source-tag-option`	Optional. Possible values are `REPLACE` and `COPY` (case-sensitive). The default value is `REPLACE`. If `COPY` is specified, the tags from the source blob will be copied to the destination blob. The source blob must be private, and the request must have permission to the Get Blob Tags operation on the source blob and the Set Blob Tags operation on the destination blob. This incurs an extra call to the `Get Blob Tags` operation on the source account. `REPLACE` will set tags that the `x-ms-tags` header specifies on the destination blob. If `x-ms-tags` specifies `REPLACE` and no tags, then no tags will be set on the destination blob. Specifying `COPY` and `x-ms-tags` will result in a 409 (Conflict) error. Supported in version 2021-04-10 and later.
`x-ms-source-if-modified-since`	Optional. A `DateTime` value. Specify this conditional header to copy the blob only if the source blob has been modified since the specified date/time. If the source blob has not been modified, Blob Storage returns status code 412 (Precondition Failed). You can't specify this header if the source is an Azure file.
`x-ms-source-if-unmodified-since`	Optional. A `DateTime` value. Specify this conditional header to copy the blob only if the source blob has not been modified since the specified date/time. If the source blob has been modified, Blob Storage returns status code 412 (Precondition Failed). You can't specify this header if the source is an Azure file.
`x-ms-source-if-match`	Optional. An `ETag` value. Specify this conditional header to copy the source blob only if its `ETag` value matches the specified value. If the values don't match, Blob Storage returns status code 412 (Precondition Failed). You can't specify this header if the source is an Azure file.
`x-ms-source-if-none-match`	Optional. An `ETag` value. Specify this conditional header to copy the blob only if its `ETag` value doesn't match the specified value. If the values are identical, Blob Storage returns status code 412 (Precondition Failed). You can't specify this header if the source is an Azure file.
`If-Modified-Since`	Optional. A `DateTime` value. Specify this conditional header to copy the blob only if the destination blob has been modified since the specified date/time. If the destination blob has not been modified, Blob Storage returns status code 412 (Precondition Failed).
`If-Unmodified-Since`	Optional. A `DateTime` value. Specify this conditional header to copy the blob only if the destination blob has not been modified since the specified date/time. If the destination blob has been modified, Blob Storage returns status code 412 (Precondition Failed).
`If-Match`	Optional. An `ETag` value. Specify an `ETag` value for this conditional header to copy the blob only if the specified `ETag` value matches the `ETag` value for an existing destination blob. If the values don't match, Blob Storage returns status code 412 (Precondition Failed).
`If-None-Match`	Optional. An `ETag` value, or the wildcard character (). Specify an `ETag` value for this conditional header to copy the blob only if the specified `ETag` value doesn't match the `ETag` value for the destination blob. Specify the wildcard character () to perform the operation only if the destination blob doesn't exist. If the specified condition isn't met, Blob Storage returns status code 412 (Precondition Failed).
`x-ms-copy-source:name`	Required. Specifies the URL of the source blob. The value can be a URL of up to 2 kibibytes (KiB) in length that specifies a blob. The value should be URL-encoded as it would appear in a request URI. The source blob must either be public or be authorized via a shared access signature. If the source blob is public, no authorization is required to perform the operation. If the size of the source blob is greater than 256 MiB, the request fails with a 409 (Conflict) error. The blob type of the source blob has to be block blob. Here are some examples of source object URLs: - `https://myaccount.blob.core.windows.net/mycontainer/myblob` - `https://myaccount.blob.core.windows.net/mycontainer/myblob?snapshot=<DateTime>` - `https://myaccount.blob.core.windows.net/mycontainer/myblob?versionid=<DateTime>`
`x-ms-copy-source-authorization: <scheme> <signature>`	Optional. Specifies the authorization scheme and signature for the copy source. For more information, see Authorize requests to Azure Storage. Only the scheme bearer is supported for Microsoft Entra. This header is supported in version 2020-10-02 and later.
`x-ms-requires-sync:true`	Required. Indicates that this is a synchronous `Copy Blob From URL` operation instead of an asynchronous `Copy Blob` operation.
`x-ms-source-content-md5`	Optional. Specifies an MD5 hash of the blob content from the URI. This hash is used to verify the integrity of the blob during transport of the data from the URI. When this header is specified, the storage service compares the hash of the content that has arrived from the copy source with this header value. The MD5 hash is not stored with the blob. If the two hashes don't match, the operation fails with error code 400 (Bad Request).
`x-ms-lease-id:<ID>`	Required if the destination blob has an active lease. The lease ID specified for this header must match the lease ID of the destination blob. If the request doesn't include the lease ID or it isn't valid, the operation fails with status code 412 (Precondition Failed). If this header is specified and the destination blob doesn't currently have an active lease, the operation fails with status code 412 (Precondition Failed). In version 2012-02-12 and later, this value must specify an active, infinite lease for a leased blob. A finite-duration lease ID fails with status code 412 (Precondition Failed).
`x-ms-client-request-id`	Optional. Provides a client-generated, opaque value with a 1-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.
`x-ms-access-tier`	Optional. Specifies the tier to be set on the target blob. This header is for page blobs on a premium account only with version 2017-04-17 and later. For a full list of supported tiers, see High-performance premium storage and managed disks for VMs. This header is supported on version 2018-11-09 and later for block blobs. Block blob tiering is supported on Blob Storage or General Purpose v2 accounts. Valid values are `Hot`, `Cool`, `Cold`, and `Archive`. Note: `Cold` tier is supported for version 2021-12-02 and later. For detailed information about block blob tiering, see Hot, cool, and archive storage tiers.

Request body

None.

Response

The response includes an HTTP status code and a set of response headers.

Status code

A successful operation returns status code 202 (Accepted).

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

Response headers

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

Response header	Description
`ETag`	If the copy is complete, contains the `ETag` value of the destination blob. If the copy isn't complete, contains the `ETag` value of the empty blob created at the start of the copy. The `ETag` value is in quotation marks.
`Last-Modified`	Returns the date/time that the copy operation to the destination blob finished.
`x-ms-request-id`	Uniquely identifies the request that was made. You can use it to troubleshoot the request. For more information, see Troubleshoot API operations.
`x-ms-version`	Indicates the version of Blob Storage that's used to execute the request.
`Date`	A UTC date/time value that indicates the time at which the service sent the response.
`x-ms-copy-id: <id>`	String identifier for this copy operation.
`x-ms-copy-status: <success>`	Indicates the state of the copy operation. A value of `success` means that the operation finished successfully.
`x-ms-client-request-id`	Can be used to troubleshoot requests and 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 is at most 1,024 visible ASCII characters. If the `x-ms-client-request-id` header is not present in the request, this header won't be present in the response.
`x-ms-request-server-encrypted: true/false`	Set to `true` if the contents of the request are successfully encrypted through the specified algorithm. Otherwise, the value is `false`.
`x-ms-encryption-scope`	Returned if the request used an encryption scope, so the client can ensure that the contents of the request are successfully encrypted through the encryption scope.

Response body

None.

Sample response

The following is a sample response for a request to copy a blob:

Response Status:  
HTTP/1.1 202 Accepted  
  
Response Headers:   
Last-Modified: <date>   
ETag: "0x8CEB669D794AFE2"  
Server: Windows-Azure-Blob/1.0 Microsoft-HTTPAPI/2.0  
x-ms-request-id: cc6b209a-b593-4be1-a38a-dde7c106f402  
x-ms-version: 2018-03-28  
x-ms-copy-id: 1f812371-a41d-49e6-b123-f4b542e851c5  
x-ms-copy-status: success  
Date: <date>

Authorization

Authorization is required when calling any data access operation in Azure Storage. The following table describes how the destination and source objects for a Copy Blob From URL operation can be authorized:

Object type	Microsoft Entra ID authorization	Shared Access Signature (SAS) authorization	Shared Key authorization (or Shared Key Lite)
Destination block blob	Yes	Yes	Yes
Source block blob in same storage account	Yes	Yes	Yes
Source block blob in another storage account	No	Yes	No

If a request specifies tags in the x-ms-tags request header, the caller must meet the authorization requirements of the Set Blob Tags operation.

You can authorize the Copy Blob From URL operation as described below. Note that a source blob in a different storage account must be authorized separately via SAS token with the Read (r) permission. For more information on source blob authorization, see the details for the request header x-ms-copy-source.

Important

Microsoft recommends using Microsoft Entra ID with managed identities to authorize requests to Azure Storage. Microsoft Entra ID provides superior security and ease of use compared to Shared Key authorization.

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, managed identity, or service principal to call the Copy Blob From URL operation, and the least privileged built-in Azure RBAC role that includes this action:

Destination blob

Azure RBAC action: Microsoft.Storage/storageAccounts/blobServices/containers/blobs/write (for writing to an existing blob) or Microsoft.Storage/storageAccounts/blobServices/containers/blobs/add/action (for writing a new blob to the destination)
Least privileged built-in role: Storage Blob Data Contributor

Source blob within same storage account

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

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 Copy Blob From URL 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 Copy Blob From URL operation using a SAS token delegated to a blob resource requires the following permission as part of the user delegation SAS token.

Operation	Object type	Signed permission
Copy Blob From URL	Destination blob (new)	Create (c) or Write (w)
Copy Blob From URL	Destination blob (existing)	Write (w)
Copy Blob From URL	Source blob (within same storage account)	Read (r)
Copy Blob From URL	Source blob (in different storage account)	Read (r)

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 Copy Blob From URL operation using a SAS token delegated to a blob resource requires the following permission as part of the service SAS token.

Operation	Object type	Signed permission
Copy Blob From URL	Destination blob (new)	Create (c) or Write (w)
Copy Blob From URL	Destination blob (existing)	Write (w)
Copy Blob From URL	Source blob (within same storage account)	Read (r)
Copy Blob From URL	Source blob (in different storage account)	Read (r)

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	Object type	Signed service	Signed resource type	Signed permission
Copy Blob From URL	Destination blob (new)	Blob (b)	Object (o)	Create (c) or Write (w)
Copy Blob From URL	Destination blob (existing)	Blob (b)	Object (o)	Write (w)
Copy Blob From URL	Source blob (within same storage account)	Blob (b)	Object (o)	Read (r)
Copy Blob From URL	Source blob (in different storage account)	Blob (b)	Object (o)	Read (r)

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

Remarks

The source and destination blob for a Copy Blob From URL operation must be a block blob.

In version 2020-10-02 and later, Microsoft Entra authorization is supported for the source of the copy operation.

The Copy Blob From URL operation always copies the entire source blob. Copying a range of bytes or set of blocks is not supported.

You can copy a source blob to a destination blob that has a different name. The destination blob can be an existing block blob, or it can be a new blob that the copy operation creates.

When you're copying from a block blob, all committed blocks and their block IDs are copied. Uncommitted blocks are not copied. At the end of the copy operation, the destination blob will have the same committed block count as the source.

The ETag value for a block blob changes when the Copy Blob From URL operation starts and when the operation finishes.

Copying blob properties and metadata

When a block blob is copied, the following system properties are copied to the destination blob with the same values:

Content-Type
Content-Encoding
Content-Language
Content-Length
Cache-Control
Content-MD5
Content-Disposition

The source blob's committed block list is also copied to the destination blob. Any uncommitted blocks are not copied.

The destination blob is always the same size as the source blob, so the value of the Content-Length header for the destination blob matches the value of that header for the source blob.

If the x-ms-tags header provides tags for the destination blob, they must be query-string encoded. Tag keys and values must conform to the naming and length requirements specified in the Set Blob Tags operation.

The x-ms-tags header can contain up to 2 kilobits of tags. If you need more tags, use the Set Blob Tags operation.

If the x-ms-tags header doesn't provide tags, then tags aren't copied from the source blob.

Copying a leased blob

The Copy Blob From URL operation only reads from the source blob, so the lease state of the source blob doesn't matter.

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 Copy Blob From URL requests based on the storage account type:

Operation	Storage account type	Billing category
Copy Blob From URL (destination account¹)	Premium block blob Standard general-purpose v2 Standard general-purpose v1	Write operations
Copy Blob From URL (source account²)	Premium block blob Standard general-purpose v2 Standard general-purpose v1	Read operations

¹The destination account is charged for one transaction to initiate the write.
²The source account incurs one transaction for each read request to the source object.

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

In addition, if the source and destination accounts reside in different regions (for example, US North and US South), bandwidth that you use to transfer the request is charged to the source storage account as egress. Egress between accounts within the same region is free.

When you copy a source blob to a destination blob that has a different name within the same account, you use additional storage resources for the new blob. The copy operation then results in a charge against the storage account's capacity usage for those additional resources.

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