Soenneker.Blob.Download 4.0.3594

Soenneker.Blob.Download

Downloads Azure blobs to temporary files, memory streams, or strings.

Installation

dotnet add package Soenneker.Blob.Download

Configuration

Provide the Azure Storage connection string through configuration:

{
  "Azure": {
    "Storage": {
      "Blob": {
        "ConnectionString": "<connection string>"
      }
    }
  }
}

Registration

using Microsoft.Extensions.DependencyInjection;
using Soenneker.Blob.Download.Registrars;

services.AddBlobDownloadUtilAsScoped();

AddBlobDownloadUtilAsSingleton() is also available when a singleton lifetime fits the application.

Usage

using Soenneker.Blob.Download.Abstract;

public sealed class DocumentStore
{
    private readonly IBlobDownloadUtil _downloads;

    public DocumentStore(IBlobDownloadUtil downloads)
    {
        _downloads = downloads;
    }

    public async ValueTask<string> ReadManifest(CancellationToken cancellationToken)
    {
        return await _downloads.DownloadToString(
            "documents",
            "manifests/latest.json",
            cancellationToken: cancellationToken);
    }
}

Download to a temporary file when the content should not be buffered in memory:

FileInfo file = await downloads.Download(
    "documents",
    "exports/archive.zip",
    cancellationToken: cancellationToken);

try
{
    // Consume file here.
}
finally
{
    file.Delete();
}

For in-memory processing, dispose the returned stream:

await using MemoryStream stream = await downloads.DownloadToMemory(
    "documents",
    "images/logo.png",
    cancellationToken: cancellationToken);

Choosing a download method

Behavior

• DownloadToMemory and DownloadToString buffer the entire blob. Prefer Download for large or untrusted content.
• The stream returned by DownloadToMemory is positioned at 0.
• Failed file downloads remove the incomplete temporary file when possible. Failed memory downloads dispose their stream.
• A missing blob is reported through Azure's RequestFailedException, including a 404 status when returned by the service.
• publicAccessType is used only if the underlying client utility creates a missing container; it does not update an existing container's access level.
• Cancellation is passed to Azure Storage and temporary resource creation.