Azure Storage Blobs Documentation

Listing Blobs in Azure Storage

This document explains how to list blobs within a container in Azure Blob Storage using various SDKs and tools. Listing blobs is a fundamental operation for managing your storage data.

Understanding Blob Listing

When you list blobs, you can retrieve a list of blob names, their metadata, and properties. Azure Storage supports several options for listing, including:

• Listing blobs at the root of a container.
• Listing blobs within a specified virtual directory (prefix).
• Using delimiters to simulate directory structures.
• Specifying the maximum number of results to return.
• Retrieving blob metadata and properties.

Methods for Listing Blobs

Using Azure CLI

The Azure Command-Line Interface (CLI) provides a straightforward way to list blobs. Use the az storage blob list command.

az storage blob list \
    --account-name  \
    --account-key  \
    --container-name  \
    --output table
                    

Replace <your-storage-account-name>, <your-storage-account-key>, and <your-container-name> with your specific details. The --output table option provides a human-readable format.

Using .NET SDK

The Azure Blob Storage client library for .NET allows programmatic listing of blobs.

using Azure.Storage.Blobs;
using System;

public class BlobLister
{
    public static void ListBlobs(string connectionString, string containerName)
    {
        BlobServiceClient blobServiceClient = new BlobServiceClient(connectionString);
        BlobContainerClient containerClient = blobServiceClient.GetBlobContainerClient(containerName);

        Console.WriteLine("Listing blobs:");
        foreach (BlobItem blobItem in containerClient.GetBlobs())
        {
            Console.WriteLine($"- {blobItem.Name}");
        }
    }
}
                    

Using Python SDK

The Azure Blob Storage client library for Python offers similar functionality.

from azure.storage.blob import BlobServiceClient

def list_blobs(connection_string, container_name):
    blob_service_client = BlobServiceClient.from_connection_string(connection_string)
    container_client = blob_service_client.get_container_client(container_name)

    print("Listing blobs:")
    for blob in container_client.list_blobs():
        print(f"- {blob.name}")

                    

Advanced Listing Options

Listing with a Prefix (Virtual Directories)

To list blobs within a specific "folder" (prefix), use the prefix parameter.

# ... (previous code) ...
    for blob in container_client.list_blobs(name_starts_with="myfolder/"):
        print(f"- {blob.name}")
                    

Using Delimiters

Simulate directory structures by using a delimiter (e.g., '/') in your listing request. This is useful for listing "directories" and their contents.

# ... (previous code) ...
    blob_list = container_client.list_blobs(delimiter='/')
    for blob_or_prefix in blob_list:
        if blob_or_prefix.get('is_prefix', False): # This is a virtual directory
            print(f"Directory: {blob_or_prefix['name']}")
        else: # This is a blob
            print(f"Blob: {blob_or_prefix['name']}")
                    

Blob Properties and Metadata

When listing blobs, you can also retrieve additional information: