How to upload a file to Azure blob and download as stream?

26 Jun 20231 minute to read

The following code snippet shows how to upload an Excel file to Azure blob and download it as stream.

C# [Cross-platform]

public static class Function1
{
  [FunctionName("Function1")]
  public static async Task<IActionResult> Run([HttpTrigger(AuthorizationLevel.Function, "get", "post", Route = null)] HttpRequest req, ILogger log)
  {
    using FileStream uploadFileStream = File.OpenRead("Sample.xlsx");

    var accountName = "Account Name";
    var accountKey = "Account Key";

    StorageSharedKeyCredential sharedKeyCredential = new StorageSharedKeyCredential(accountName, accountKey);

    string blobUri = "https://" + accountName + ".blob.core.windows.net";

    BlobServiceClient blobServiceClient = new BlobServiceClient(new Uri(blobUri), sharedKeyCredential);

    BlobContainerClient containerClient = blobServiceClient.GetBlobContainerClient("Container Name");

    var filename = "AzureFile_Upload.xlsx";

    BlobClient blobClientUpload = containerClient.GetBlobClient(filename);
    await blobClientUpload.UploadAsync(uploadFileStream, true);

    MemoryStream readStream = new MemoryStream();
    BlobClient blobClientRead = containerClient.GetBlobClient(filename);
    await blobClientRead.DownloadToAsync(readStream);

    readStream.Position = 0;

    FileStream outputStream = new FileStream("Output.xlsx", FileMode.Create, FileAccess.Write);
    readStream.CopyTo(outputStream);

    return new OkObjectResult("done");
  }
}