Azure Blob Storage Uploads

Overview

Shiny HTTP Transfers includes a built-in fluent builder for uploading files to Azure Blob Storage. The AzureBlobStorageUploadRequest handles all Azure-specific headers and authentication, producing a standard HttpTransferRequest that runs as a background transfer.

Quick Start

IHttpTransferManager manager; // injected

var request = new AzureBlobStorageUploadRequest("/path/to/file.pdf")
    .WithBlobContainer("myaccount", "mycontainer")
    .WithSasToken("sv=2023-01-01&ss=b&srt=o&sp=w&se=2026-12-31&sig=...")
    .Build();

await manager.Queue(request);

Authentication

Azure Blob Storage supports two authentication methods.

SAS Token (Recommended)

A Shared Access Signature provides scoped, time-limited access without exposing your storage account key.

var request = new AzureBlobStorageUploadRequest("/path/to/file.pdf")
    .WithBlobContainer("myaccount", "mycontainer")
    .WithSasToken("sv=2023-01-01&ss=b&srt=o&sp=w&se=2026-12-31&sig=abc123")
    .Build();

The SAS token is appended as a query string to the blob URL.

Shared Key

For server-side or trusted environments where the storage key is available.

var request = new AzureBlobStorageUploadRequest("/path/to/file.pdf")
    .WithBlobContainer("myaccount", "mycontainer")
    .WithSharedKeyAuthorization("your-shared-key")
    .Build();

This adds Authorization, x-ms-date, and x-ms-version headers automatically.

Builder Methods

Method	Description
WithBlobContainer(tenant, container)	Sets the URI to https://{tenant}.blob.core.windows.net/{container}
WithCustomUri(uri)	Use a custom Azure endpoint URL
WithSasToken(token)	Authenticate with a SAS token
WithSharedKeyAuthorization(key, version?, date?)	Authenticate with a shared key
WithRemoteFileName(name)	Set the blob name (defaults to local filename)
WithMeteredConnection()	Allow upload on metered/cellular networks
WithHeader(key, value)	Add a custom HTTP header

Builder Properties

Property	Type	Description
LocalFilePath	string	Path to the file being uploaded
Identifier	string?	Transfer identifier (auto-generated if not set)
Uri	string?	Target blob URL
RemoteFileName	string?	Blob name (defaults to local filename)
UseMeteredConnection	bool	Allow metered network transfers
Headers	Dictionary<string, string>	Custom headers

Auto-Generated Headers

When Build() is called, these headers are automatically set:

Header	Value
Content-Length	File size in bytes
x-ms-blob-type	BlockBlob
Content-Disposition	attachment; filename="{name}"

Full Example

IHttpTransferManager manager; // injected

var builder = new AzureBlobStorageUploadRequest("/path/to/photo.jpg")
    .WithBlobContainer("mystorageaccount", "uploads")
    .WithSasToken("sv=2023-01-01&ss=b&srt=o&sp=w&se=2026-12-31&sig=abc123")
    .WithRemoteFileName("photos/vacation.jpg")
    .WithMeteredConnection();

var request = builder.Build();
var transfer = await manager.Queue(request);

Tip

Combine Azure uploads with HttpTransferDelegate to automatically refresh SAS tokens when they expire. Override OnAuthorizationFailed to generate a new token and return an updated request. See the Delegate documentation for details.

Refreshing Expired SAS Tokens

Use HttpTransferDelegate to handle token expiration during long uploads.

public partial class MyTransferDelegate(
    ILogger<MyTransferDelegate> logger,
    IHttpTransferManager manager,
    ISasTokenService tokenService
) : HttpTransferDelegate(logger, manager, maxErrorRetries: 3)
{
    protected override async Task<HttpTransferRequest?> OnAuthorizationFailed(
        HttpTransferRequest request,
        int retries
    )
    {
        if (retries > 3)
            return null; // give up

        var newToken = await tokenService.GetFreshSasTokenAsync();
        // Rebuild the URI with the new token
        var baseUri = request.Uri.Split('?')[0];
        return request with { Uri = $"{baseUri}?{newToken}" };
    }
}