To bulk download files from Azure Blob Storage using C#, you can use the Azure.Storage.Blobs SDK. Below is a step-by-step guide:
1. Install the required NuGet package
Install Azure.Storage.Blobs using NuGet Package Manager:
Install-Package Azure.Storage.Blobs
2. Set up connection details
- Azure Storage Account connection string
- Blob container name
- Local folder path for saving the downloaded files
3. List and Download Blobs in Bulk
- Use BlobContainerClient to get the list of blobs.
- Download each blob asynchronously using DownloadToAsync
using System;
using System.IO;
using System.Threading.Tasks;
using Azure.Storage.Blobs;
using Azure.Storage.Blobs.Models;
class Program
{
private const string connectionString = "Your_Azure_Storage_Connection_String";
private const string containerName = "your-container-name";
private const string downloadFolderPath = @"C:\DownloadedBlobs"; // Local save path
static async Task Main()
{
await BulkDownloadBlobsAsync();
}
private static async Task BulkDownloadBlobsAsync()
{
try
{
BlobContainerClient containerClient = new BlobContainerClient(connectionString, containerName);
await foreach (BlobItem blobItem in containerClient.GetBlobsAsync())
{
string blobName = blobItem.Name;
string localFilePath = Path.Combine(downloadFolderPath, blobName);
// Create directories if they don't exist
Directory.CreateDirectory(Path.GetDirectoryName(localFilePath));
Console.WriteLine($"Downloading: {blobName}");
BlobClient blobClient = containerClient.GetBlobClient(blobName);
await blobClient.DownloadToAsync(localFilePath);
}
Console.WriteLine("Bulk download completed.");
}
catch (Exception ex)
{
Console.WriteLine($"Error: {ex.Message}");
}
}
}
Explanation
- Initialize BlobContainerClient using the storage account connection string.
- List all blobs in the container using GetBlobsAsync().
- Iterate over the blobs and download each file asynchronously.
- Ensure directory structure exists before saving files locally.
- Handle exceptions gracefully.
Optimizing for Large Blob Containers
If your container has thousands of blobs, consider:
- Parallel downloads using Task.WhenAll().
- Filtering blobs by prefix (e.g., download only specific folders).
- Resuming downloads by checking if the file already exists.