DuckTyping.Azure.BlobService 1.1.0

DuckTyping.Azure.BlobService

A service that lets you easily connect to the azure blob service.

Configuration

Add the Blob storage:

• AccountName
• URL (e.g. https://your-account-name.blob.core.windows.net)
• Access key

Find configuration values in Azure

In Azure, you can find the account name in the "Overview" section. Replace "your-account-name" in the URL. In this example the URL should be "https://ducktypingnameexample.blob.core.windows.net"

The access key is available in the "Security + networking" - "Access keys" section.

Create the Container

The Blob storage container should have the access level set to Private.

Configure Program.cs

In the configuration section of Program.cs add the following lines:

// Program.cs

var builder = WebApplication.CreateBuilder(args);

builder.Services.AddBlobClient(options =>
{
    options.AccountName = Environment.GetEnvironmentVariable("BLOB_STORAGE_ACCOUNTNAME");
    options.Url = Environment.GetEnvironmentVariable("BLOB_STORAGE_URL");
    options.Key = Environment.GetEnvironmentVariable("BLOB_STORAGE_KEY");
});

var app = builder.Build();

Or if you prefer to use the appsettings.json Configurations

//appsettings.json

{
  "BlobStorage": {
    "AccountName": "your-account-name",
    "Url": "https://your-account-name.blob.core.windows.net",
    "Key": "your-access-key"
  }
}

Then add these lines in Program.cs

// Program.cs

var builder = WebApplication.CreateBuilder(args);

builder.Services.AddBlobClient(options =>
{
    options.AccountName = builder.Configuration["BlobStorage:AccountName"]!;
    options.Url = builder.Configuration["BlobStorage:Url"]!;
    options.Key = builder.Configuration["BlobStorage:Key"]!;
});

var app = builder.Build();

Use the client

Inject client

Import the namespace ducktyping.azure.blobservice and inject the service with dependency injection.

// SomeClass.cs

using DuckTyping.Azure.BlobService;

public class MyService(IBlobClient blobClient)
{
    private readonly IBlobClient _blobClient = blobClient;

    public async Task UploadFileAsync()
    {
        ...
    }
}

Upload file

You can upload a file to a specified blob container using the UploadAsync method. The file will be stored in Azure Blob Storage with the name specified by fileName.

If the container specified by containerName does not exist in your storage account, a BlobStorageException will be thrown.

// SomeClass.cs

using DuckTyping.Azure.BlobService;

public class MyService(IBlobClient blobClient)
{
    private readonly IBlobClient _blobClient = blobClient;

    public async Task UploadFileAsync()
    {
        using var stream = File.OpenRead("example.pdf");

        await _blobClient.UploadAsync(
            containerName: "my-container",
            fileName: "example.pdf",
            contentType: "application/pdf",
            stream: stream
        );
    }
}

Generate URI with SAS token

A Shared Access Signature (SAS) token is a secure, time-limited access token for a blob resource in Azure Blob Storage.

By default, the generated SAS URI:

• Grants read-only access to the specified blob.
• Is valid for 5 minutes from the time of generation.

To enable write access in addition to read, set writePermission = true.

// SomeClass.cs

using DuckTyping.Azure.BlobService;

public class MyService(IBlobClient blobClient)
{
    private readonly IBlobClient _blobClient = blobClient;

    public async Task<Uri> GenerateSasUriAsync()
    {
        var sasUri = await _blobClient.GenerateBlobSasUriAsync(
            containerName: containerName,
            blobName: blobName,
            writePermission: false // Set to true if you need write access
        );

        return sasUri;
    }
}

You can access the uploaded file with the returned URI