Я следовал этому примеру из GitHub для передачи файлов в хранилище BLOB-объектов Azure. Программа создает файл в локальной папке MyDocuments для загрузки в контейнер BLOB-объектов. После создания файла он загружает его в контейнер. Можно ли создавать объекты JSON в памяти и отправлять их в хранилище BLOB-объектов Azure без предварительной записи этого файла на жесткий диск?
namespace storage_blobs_dotnet_quickstart
{
using Microsoft.Azure.Storage;
using Microsoft.Azure.Storage.Blob;
using System;
using System.IO;
using System.Threading.Tasks;
public static class Program
{
public static void Main()
{
Console.WriteLine("Azure Blob Storage - .NET quickstart sample");
Console.WriteLine();
ProcessAsync().GetAwaiter().GetResult();
Console.WriteLine("Press any key to exit the sample application.");
Console.ReadLine();
}
private static async Task ProcessAsync()
{
CloudStorageAccount storageAccount = null;
CloudBlobContainer cloudBlobContainer = null;
string sourceFile = null;
string destinationFile = null;
// Retrieve the connection string for use with the application. The storage connection string is stored
// in an environment variable on the machine running the application called storageconnectionstring.
// If the environment variable is created after the application is launched in a console or with Visual
// Studio, the shell needs to be closed and reloaded to take the environment variable into account.
string storageConnectionString = Environment.GetEnvironmentVariable("storageconnectionstring");
// Check whether the connection string can be parsed.
if (CloudStorageAccount.TryParse(storageConnectionString, out storageAccount))
{
try
{
// Create the CloudBlobClient that represents the Blob storage endpoint for the storage account.
CloudBlobClient cloudBlobClient = storageAccount.CreateCloudBlobClient();
// Create a container called 'quickstartblobs' and append a GUID value to it to make the name unique.
cloudBlobContainer = cloudBlobClient.GetContainerReference("quickstartblobs" + Guid.NewGuid().ToString());
await cloudBlobContainer.CreateAsync();
Console.WriteLine("Created container '{0}'", cloudBlobContainer.Name);
Console.WriteLine();
// Set the permissions so the blobs are public.
BlobContainerPermissions permissions = new BlobContainerPermissions
{
PublicAccess = BlobContainerPublicAccessType.Blob
};
await cloudBlobContainer.SetPermissionsAsync(permissions);
// Create a file in your local MyDocuments folder to upload to a blob.
string localPath = Environment.GetFolderPath(Environment.SpecialFolder.MyDocuments);
string localFileName = "QuickStart_" + Guid.NewGuid().ToString() + ".txt";
sourceFile = Path.Combine(localPath, localFileName);
// Write text to the file.
File.WriteAllText(sourceFile, "Hello, World!");
Console.WriteLine("Temp file = {0}", sourceFile);
Console.WriteLine("Uploading to Blob storage as blob '{0}'", localFileName);
Console.WriteLine();
// Get a reference to the blob address, then upload the file to the blob.
// Use the value of localFileName for the blob name.
CloudBlockBlob cloudBlockBlob = cloudBlobContainer.GetBlockBlobReference(localFileName);
await cloudBlockBlob.UploadFromFileAsync(sourceFile);
// List the blobs in the container.
Console.WriteLine("Listing blobs in container.");
BlobContinuationToken blobContinuationToken = null;
do
{
var resultSegment = await cloudBlobContainer.ListBlobsSegmentedAsync(null, blobContinuationToken);
// Get the value of the continuation token returned by the listing call.
blobContinuationToken = resultSegment.ContinuationToken;
foreach (IListBlobItem item in resultSegment.Results)
{
Console.WriteLine(item.Uri);
}
} while (blobContinuationToken != null); // Loop while the continuation token is not null.
Console.WriteLine();
// Download the blob to a local file, using the reference created earlier.
// Append the string "_DOWNLOADED" before the .txt extension so that you can see both files in MyDocuments.
destinationFile = sourceFile.Replace(".txt", "_DOWNLOADED.txt");
Console.WriteLine("Downloading blob to {0}", destinationFile);
Console.WriteLine();
await cloudBlockBlob.DownloadToFileAsync(destinationFile, FileMode.Create);
}
catch (StorageException ex)
{
Console.WriteLine("Error returned from the service: {0}", ex.Message);
}
finally
{
Console.WriteLine("Press any key to delete the sample files and example container.");
Console.ReadLine();
// Clean up resources. This includes the container and the two temp files.
Console.WriteLine("Deleting the container and any blobs it contains");
if (cloudBlobContainer != null)
{
await cloudBlobContainer.DeleteIfExistsAsync();
}
Console.WriteLine("Deleting the local source file and local downloaded files");
Console.WriteLine();
File.Delete(sourceFile);
File.Delete(destinationFile);
}
}
else
{
Console.WriteLine(
"A connection string has not been defined in the system environment variables. " +
"Add a environment variable named 'storageconnectionstring' with your storage " +
"connection string as a value.");
}
}
}
}