Blob to file access

The following sample code provides an example of both single and multiple download approaches. It also offers a simplified approach to searching all containers for specific files using a wildcard. Because some environments may have hundreds of thousands of resources, using the -MaxCount parameter is recommended. The result displays the storage account and container names and provides a list of the files downloaded.

A container exposes both system properties and user-defined metadata. System properties exist on each Blob Storage resource. Some properties are read-only, while others can be read or set. Under the covers, some system properties map to certain standard HTTP headers. User-defined metadata consists of one or more name-value pairs that you specify for a Blob Storage resource.

You can use metadata to store additional values with the resource. Metadata values are for your own purposes only, and don't affect how the resource behaves. To read blob properties or metadata, you must first retrieve the blob from the service. Use the Get-AzStorageBlob cmdlet to retrieve a blob's properties and metadata, but not its content. Next, use the BlobClient. GetProperties method to fetch the blob's properties. The properties or metadata can then be read or set as needed.

As shown in the previous example, there's no metadata associated with a blob initially, though it can be added when necessary. To update blob metadata, you'll use the BlobClient. UpdateMetadata method. This method only accepts key-value pairs stored in a generic IDictionary object. For more information, see the BlobClient class definition. The example below first updates and then commits a blob's metadata, and then retrieves it. The sample blob is flushed from memory to ensure the metadata isn't being read from the in-memory object.

There are many scenarios in which blobs of different types may be copied. Examples in this article are limited to block blobs. For a simplified copy operation within the same storage account, use the Copy-AzStorageBlob cmdlet. Because the operation is copying a blob within the same storage account, it's a synchronous operation.

Cross-account operations are asynchronous. You should consider the use of AzCopy for ease and performance, especially when copying blobs between storage accounts. AzCopy is a command-line utility that you can use to copy blobs or files to or from a storage account. Find out more about how to Get started with AzCopy. The example below copies the bannerphoto. Both containers exist within the same storage account. The result verifies the success of the copy operation.

You can use the -Force parameter to overwrite an existing blob with the same name at the destination. This operation effectively replaces the destination blob.

It also removes any uncommitted blocks and overwrites the destination blob's metadata. The source blob for a copy operation may be a block blob, an append blob, a page blob, or a snapshot. If the destination blob already exists, it must be of the same blob type as the source blob. An existing destination blob will be overwritten. The destination blob can't be modified while a copy operation is in progress. A destination blob can only have one outstanding copy operation.

In other words, a blob can't be the destination for multiple pending copy operations. When you copy a blob within the same storage account, it's a synchronous operation. When you copy across accounts it's an asynchronous operation. The entire source blob or file is always copied.

Copying a range of bytes or set of blocks is not supported. When a blob is copied, it's system properties are copied to the destination blob with the same values.

A snapshot is a read-only version of a blob that's taken at a point in time. A snapshot of a blob is identical to its base blob, except that the blob URI has a DateTime value appended to the blob URI to indicate the time at which the snapshot was taken. The only distinction between the base blob and the snapshot is the appended DateTime value.

Any leases associated with the base blob do not affect the snapshot. You cannot acquire a lease on a snapshot. Built-in roles that support Microsoft. When you attempt to access blob data in the Azure portal, the portal first checks whether you have been assigned a role with Microsoft.

If you have been assigned a role with this action, then the portal uses the account key for accessing blob data. If you have not been assigned a role with this action, then the portal attempts to access data using your Azure AD account.

When a storage account is locked with an Azure Resource Manager ReadOnly lock, the List Keys operation is not permitted for that storage account. For this reason, when the account is locked with a ReadOnly lock, users must use Azure AD credentials to access blob data in the portal.

The classic subscription administrator roles Service Administrator and Co-Administrator include the equivalent of the Azure Resource Manager Owner role. The Owner role includes all actions, including the Microsoft.

For more information, see Classic subscription administrator roles, Azure roles, and Azure AD administrator roles. To access blob data from the Azure portal using your Azure AD account, both of the following statements must be true for you:. The Azure Resource Manager Reader role permits users to view storage account resources, but not modify them.

It does not provide read permissions to data in Azure Storage, but only to account management resources. The Reader role is necessary so that users can navigate to blob containers in the Azure portal. For information about the built-in roles that support access to blob data, see Authorize access to blobs using Azure Active Directory.

Custom roles can support different combinations of the same permissions provided by the built-in roles. For more information about creating Azure custom roles, see Azure custom roles and Understand role definitions for Azure resources.

The preview version of Storage Explorer in the Azure portal does not support using Azure AD credentials to view and modify blob data. Storage Explorer in the Azure portal always uses the account keys to access data. To use Storage Explorer in the Azure portal, you must be assigned a role that includes Microsoft.

To view blob data in the portal, navigate to the Overview for your storage account, and click on the links for Blobs. Alternatively you can navigate to the Containers section in the menu.

This link appears to be asking the same question, and the response says something about 'role-based authentication' - I get the concept of adding roles to users, and using those as the authorization, but even as the owner of the blob container I can't seem to just link to myservice. Nor a way to link to myservice. If the access level of the container is set to public anonymous, we can directly access the Blob Uri in the browser to access the blobs.

Instead, it will give ResourceNotFound error. Even the proper role is assigned in the Role Assignments for the blob storage, still we would not be able to access the Blob Uri from the browser without appending the SAS token. Because, opening the direct Blob Uri in the browser doesn't trigger the OAuth flow. Even though, it is not possible to access the blob Uri from browser and download the files, there are other ways to accomplish this. If you want to access the blob data from the browser, we can use function app.

We can enable the function app for authentication. Then the authenticated users can access the blob data via function app.

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