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使用 .NET 11.x 版用戶端連結庫的 Azure Blob 記憶體程式代碼範例

本文說明使用適用於 .NET 的 Azure Blob 記憶體用戶端連結庫 11.x 版的程式代碼範例。

在 2023 年 3 月 31 日，我們已淘汰不符合目前 Azure SDK 指導方針的 Azure SDK 程式庫支援。 新的 Azure SDK 程式庫會定期更新，以促進一致的體驗並加強您的安全性態勢。 建議您轉換至新的 Azure SDK 程式庫，以利用新功能和重大安全性更新。

雖然較舊的程式庫仍可在 2023 年 3 月 31 日之後使用，但它們將不再收到 Microsoft 的官方支援和更新。 如需詳細資訊，請參閱支援中止公告。

建立快照

若要使用適用於 .NET 的 Azure 儲存體用戶端程式庫 11.x 版建立區塊 Blob 的快照，請使用下列其中一種方法：

下列程式代碼範例示範如何使用 11.x 版建立快照集。 此範例會在建立快照集時指定快照集的其他元數據。

private static async Task CreateBlockBlobSnapshot(CloudBlobContainer container)
{
    // Create a new block blob in the container.
    CloudBlockBlob baseBlob = container.GetBlockBlobReference("sample-base-blob.txt");

    // Add blob metadata.
    baseBlob.Metadata.Add("ApproxBlobCreatedDate", DateTime.UtcNow.ToString());

    try
    {
        // Upload the blob to create it, with its metadata.
        await baseBlob.UploadTextAsync(string.Format("Base blob: {0}", baseBlob.Uri.ToString()));

        // Sleep 5 seconds.
        System.Threading.Thread.Sleep(5000);

        // Create a snapshot of the base blob.
        // You can specify metadata at the time that the snapshot is created.
        // If no metadata is specified, then the blob's metadata is copied to the snapshot.
        Dictionary<string, string> metadata = new Dictionary<string, string>();
        metadata.Add("ApproxSnapshotCreatedDate", DateTime.UtcNow.ToString());
        await baseBlob.CreateSnapshotAsync(metadata, null, null, null);
        Console.WriteLine(snapshot.SnapshotQualifiedStorageUri.PrimaryUri);
    }
    catch (StorageException e)
    {
        Console.WriteLine(e.Message);
        Console.ReadLine();
        throw;
    }
}

刪除快照集

若要使用適用於 .NET 的 Azure 儲存體用戶端程式庫 11.x 版刪除 blob 及其快照，請使用下列其中一種刪除 blob 的方法，並包含 DeleteSnapshotsOption 列舉：

下列程式代碼範例示範如何在 .NET 中刪除 Blob 及其快照集，其中 blockBlob 是類型為 [CloudBlockBlob][dotnet_CloudBlockBlob]的物件：

await blockBlob.DeleteIfExistsAsync(DeleteSnapshotsOption.IncludeSnapshots, null, null, null);

建立預存存取原則

若要在具有適用於 Azure 記憶體之 .NET 用戶端連結庫 11.x 版的容器上建立預存存取原則，請呼叫下列其中一種方法：

下列範例會建立一天的預存存取原則，並授與讀取、寫入和清單許可權：

private static async Task CreateStoredAccessPolicyAsync(CloudBlobContainer container, string policyName)
{
    // Create a new stored access policy and define its constraints.
    // The access policy provides create, write, read, list, and delete permissions.
    SharedAccessBlobPolicy sharedPolicy = new SharedAccessBlobPolicy()
    {
        // When the start time for the SAS is omitted, the start time is assumed to be the time when Azure Storage receives the request.
        SharedAccessExpiryTime = DateTime.UtcNow.AddHours(24),
        Permissions = SharedAccessBlobPermissions.Read | SharedAccessBlobPermissions.List |
            SharedAccessBlobPermissions.Write
    };

    // Get the container's existing permissions.
    BlobContainerPermissions permissions = await container.GetPermissionsAsync();

    // Add the new policy to the container's permissions, and set the container's permissions.
    permissions.SharedAccessPolicies.Add(policyName, sharedPolicy);
    await container.SetPermissionsAsync(permissions);
}

為 Blob 容器建立服務 SAS

若要建立容器的服務 SAS，請呼叫 CloudBlobContainer.GetSharedAccessSignature 方法。

private static string GetContainerSasUri(CloudBlobContainer container,
                                         string storedPolicyName = null)
{
    string sasContainerToken;

    // If no stored policy is specified, create a new access policy and define its constraints.
    if (storedPolicyName == null)
    {
        // Note that the SharedAccessBlobPolicy class is used both to define
        // the parameters of an ad hoc SAS, and to construct a shared access policy
        // that is saved to the container's shared access policies.
        SharedAccessBlobPolicy adHocPolicy = new SharedAccessBlobPolicy()
        {
            // When the start time for the SAS is omitted, the start time is assumed
            // to be the time when the storage service receives the request. Omitting
            // the start time for a SAS that is effective immediately helps to avoid clock skew.
            SharedAccessExpiryTime = DateTime.UtcNow.AddHours(24),
            Permissions = SharedAccessBlobPermissions.Write | SharedAccessBlobPermissions.List
        };

        // Generate the shared access signature on the container,
        // setting the constraints directly on the signature.
        sasContainerToken = container.GetSharedAccessSignature(adHocPolicy, null);

        Console.WriteLine("SAS for blob container (ad hoc): {0}", sasContainerToken);
        Console.WriteLine();
    }
    else
    {
        // Generate the shared access signature on the container. In this case,
        // all of the constraints for the shared access signature are specified
        // on the stored access policy, which is provided by name. It is also possible
        // to specify some constraints on an ad hoc SAS and others on the stored access policy.
        sasContainerToken = container.GetSharedAccessSignature(null, storedPolicyName);

        Console.WriteLine("SAS for container (stored access policy): {0}", sasContainerToken);
        Console.WriteLine();
    }

    // Return the URI string for the container, including the SAS token.
    return container.Uri + sasContainerToken;
}

建立 Blob 的服務共享存取簽章 (SAS)

若要建立 Blob 的服務 SAS，請呼叫 CloudBlob.GetSharedAccessSignature 方法。

private static string GetBlobSasUri(CloudBlobContainer container,
                                    string blobName,
                                    string policyName = null)
{
    string sasBlobToken;

    // Get a reference to a blob within the container.
    // Note that the blob may not exist yet, but a SAS can still be created for it.
    CloudBlockBlob blob = container.GetBlockBlobReference(blobName);

    if (policyName == null)
    {
        // Create a new access policy and define its constraints.
        // Note that the SharedAccessBlobPolicy class is used both to define the parameters
        // of an ad hoc SAS, and to construct a shared access policy that is saved to
        // the container's shared access policies.
        SharedAccessBlobPolicy adHocSAS = new SharedAccessBlobPolicy()
        {
            // When the start time for the SAS is omitted, the start time is assumed to be
            // the time when the storage service receives the request. Omitting the start time
            // for a SAS that is effective immediately helps to avoid clock skew.
            SharedAccessExpiryTime = DateTime.UtcNow.AddHours(24),
            Permissions = SharedAccessBlobPermissions.Read |
                          SharedAccessBlobPermissions.Write |
                          SharedAccessBlobPermissions.Create
        };

        // Generate the shared access signature on the blob,
        // setting the constraints directly on the signature.
        sasBlobToken = blob.GetSharedAccessSignature(adHocSAS);

        Console.WriteLine("SAS for blob (ad hoc): {0}", sasBlobToken);
        Console.WriteLine();
    }
    else
    {
        // Generate the shared access signature on the blob. In this case, all of the constraints
        // for the SAS are specified on the container's stored access policy.
        sasBlobToken = blob.GetSharedAccessSignature(null, policyName);

        Console.WriteLine("SAS for blob (stored access policy): {0}", sasBlobToken);
        Console.WriteLine();
    }

    // Return the URI string for the container, including the SAS token.
    return blob.Uri + sasBlobToken;
}

建立帳戶 SAS

若要建立容器的帳戶 SAS，請呼叫 CloudStorageAccount.GetSharedAccessSignature 方法。

下列程式碼範例建立一個帳戶 SAS，對 Blob 和檔案服務有效，賦予客戶端讀取、寫入和列出服務層級 API 的許可權。 帳戶 SAS 會將通訊協定限制為 HTTPS，因此必須使用 HTTPS 提出要求。 請記得以您自己的值取代角括號中的預留位置值：

static string GetAccountSASToken()
{
    // To create the account SAS, you need to use Shared Key credentials. Modify for your account.
    const string ConnectionString = "DefaultEndpointsProtocol=https;AccountName=<storage-account>;AccountKey=<account-key>";
    CloudStorageAccount storageAccount = CloudStorageAccount.Parse(ConnectionString);

    // Create a new access policy for the account.
    SharedAccessAccountPolicy policy = new SharedAccessAccountPolicy()
        {
            Permissions = SharedAccessAccountPermissions.Read | 
                          SharedAccessAccountPermissions.Write | 
                          SharedAccessAccountPermissions.List,
            Services = SharedAccessAccountServices.Blob | SharedAccessAccountServices.File,
            ResourceTypes = SharedAccessAccountResourceTypes.Service,
            SharedAccessExpiryTime = DateTime.UtcNow.AddHours(24),
            Protocols = SharedAccessProtocol.HttpsOnly
        };

    // Return the SAS token.
    return storageAccount.GetSharedAccessSignature(policy);
}

從用戶端使用帳戶 SAS

在此程式碼片段中，以您的儲存帳戶名稱替換 <storage-account> 佔位符。

static void UseAccountSAS(string sasToken)
{
    // Create new storage credentials using the SAS token.
    StorageCredentials accountSAS = new StorageCredentials(sasToken);
    // Use these credentials and the account name to create a Blob service client.
    CloudStorageAccount accountWithSAS = new CloudStorageAccount(accountSAS, "<storage-account>", endpointSuffix: null, useHttps: true);
    CloudBlobClient blobClientWithSAS = accountWithSAS.CreateCloudBlobClient();

    // Now set the service properties for the Blob client created with the SAS.
    blobClientWithSAS.SetServiceProperties(new ServiceProperties()
    {
        HourMetrics = new MetricsProperties()
        {
            MetricsLevel = MetricsLevel.ServiceAndApi,
            RetentionDays = 7,
            Version = "1.0"
        },
        MinuteMetrics = new MetricsProperties()
        {
            MetricsLevel = MetricsLevel.ServiceAndApi,
            RetentionDays = 7,
            Version = "1.0"
        },
        Logging = new LoggingProperties()
        {
            LoggingOperations = LoggingOperations.All,
            RetentionDays = 14,
            Version = "1.0"
        }
    });

    // The permissions granted by the account SAS also permit you to retrieve service properties.
    ServiceProperties serviceProperties = blobClientWithSAS.GetServiceProperties();
    Console.WriteLine(serviceProperties.HourMetrics.MetricsLevel);
    Console.WriteLine(serviceProperties.HourMetrics.RetentionDays);
    Console.WriteLine(serviceProperties.HourMetrics.Version);
}

Blob 的樂觀並發控制

程式代碼範例：

public void DemonstrateOptimisticConcurrencyBlob(string containerName, string blobName)
{
    Console.WriteLine("Demonstrate optimistic concurrency");

    // Parse connection string and create container.
    CloudStorageAccount storageAccount = CloudStorageAccount.Parse(ConnectionString);
    CloudBlobClient blobClient = storageAccount.CreateCloudBlobClient();
    CloudBlobContainer container = blobClient.GetContainerReference(containerName);
    container.CreateIfNotExists();

    // Create test blob. The default strategy is last writer wins, so
    // write operation will overwrite existing blob if present.
    CloudBlockBlob blockBlob = container.GetBlockBlobReference(blobName);
    blockBlob.UploadText("Hello World!");

    // Retrieve the ETag from the newly created blob.
    string originalETag = blockBlob.Properties.ETag;
    Console.WriteLine("Blob added. Original ETag = {0}", originalETag);

    /// This code simulates an update by another client.
    string helloText = "Blob updated by another client.";
    // No ETag was provided, so original blob is overwritten and ETag updated.
    blockBlob.UploadText(helloText);
    Console.WriteLine("Blob updated. Updated ETag = {0}", blockBlob.Properties.ETag);

    // Now try to update the blob using the original ETag value.
    try
    {
        Console.WriteLine(@"Attempt to update blob using original ETag
                            to generate if-match access condition");
        blockBlob.UploadText(helloText, accessCondition: AccessCondition.GenerateIfMatchCondition(originalETag));
    }
    catch (StorageException ex)
    {
        if (ex.RequestInformation.HttpStatusCode == (int)HttpStatusCode.PreconditionFailed)
        {
            Console.WriteLine(@"Precondition failure as expected.
                                Blob's ETag does not match.");
        }
        else
        {
            throw;
        }
    }
    Console.WriteLine();
}

Blob 的悲觀並發控制

程式代碼範例：

public void DemonstratePessimisticConcurrencyBlob(string containerName, string blobName)
{
    Console.WriteLine("Demonstrate pessimistic concurrency");

    // Parse connection string and create container.
    CloudStorageAccount storageAccount = CloudStorageAccount.Parse(ConnectionString);
    CloudBlobClient blobClient = storageAccount.CreateCloudBlobClient();
    CloudBlobContainer container = blobClient.GetContainerReference(containerName);
    container.CreateIfNotExists();

    CloudBlockBlob blockBlob = container.GetBlockBlobReference(blobName);
    blockBlob.UploadText("Hello World!");
    Console.WriteLine("Blob added.");

    // Acquire lease for 15 seconds.
    string lease = blockBlob.AcquireLease(TimeSpan.FromSeconds(15), null);
    Console.WriteLine("Blob lease acquired. Lease = {0}", lease);

    // Update blob using lease. This operation should succeed.
    const string helloText = "Blob updated";
    var accessCondition = AccessCondition.GenerateLeaseCondition(lease);
    blockBlob.UploadText(helloText, accessCondition: accessCondition);
    Console.WriteLine("Blob updated using an exclusive lease");

    // Simulate another client attempting to update to blob without providing lease.
    try
    {
        // Operation will fail as no valid lease was provided.
        Console.WriteLine("Now try to update blob without valid lease.");
        blockBlob.UploadText("Update operation will fail without lease.");
    }
    catch (StorageException ex)
    {
        if (ex.RequestInformation.HttpStatusCode == (int)HttpStatusCode.PreconditionFailed)
        {
            Console.WriteLine(@"Precondition failure error as expected.
                                Blob lease not provided.");
        }
        else
        {
            throw;
        }
    }

    // Release lease proactively.
    blockBlob.ReleaseLease(accessCondition);
    Console.WriteLine();
}

使用 Blob 記憶體建置高可用性應用程式

下載 範例專案、解壓縮 storage-dotnet-circuit-breaker-pattern-ha-apps-using-ra-grs.zip 檔案，然後流覽至 v11 資料夾以尋找項目檔。

您也可以使用 git ，將應用程式的複本下載到您的開發環境。 v11資料夾中的範例專案包含主控台應用程式。

git clone https://github.com/Azure-Samples/storage-dotnet-circuit-breaker-pattern-ha-apps-using-ra-grs.git

設置樣本

在應用程式中，您必須提供記憶體帳戶的連接字串。 您可以在執行應用程式的本機電腦上，將此連接字串儲存在環境變數內。 根據您的作業系統，請遵循下列其中一個範例來建立環境變數。

在 Azure 入口網站中，瀏覽至您的儲存體帳戶。 在儲存體帳戶中選取 [設定] 下的 [存取金鑰]。 從主要或次要金鑰複製連接字串。 根據您的作業系統執行以下其中一個命令，將 <yourconnectionstring> 替換為您的實際連接字串。 此命令會將環境變數儲存至本機計算機。 在 Windows 中，您需要重新載入 命令提示字元 或使用的殼層，環境變數才會生效。

執行主控台應用程式

在 Visual Studio 中，按下 F5 或選取 [啟動]，開始對應用程式進行偵錯。 如果已設定套件還原，Visual Studio 會自動還原遺漏的 NuGet 套件，請瀏覽 安裝及重新安裝套件的套件還原功能 以深入瞭解。

主控台視窗隨即啟動，應用程式會開始執行。 應用程式會將 HelloWorld.png 映像從解決方案上傳至記憶體帳戶。 應用程式會檢查以確保映像已復寫至次要 RA-GZRS 端點。 然後，它會開始下載映射最多 999 次。 每個讀取都會以 P 或 S 表示。其中 P 代表主要端點， 而 S 代表次要端點。

在範例程式代碼中， RunCircuitBreakerAsync 檔案中 Program.cs 的工作是用來使用 DownloadToFileAsync 方法從記憶體帳戶下載映像。 下載之前，會定義 OperationContext 。 操作情境定義了當下載成功完成時觸發的事件處理程式，或者當下載失敗並正在重試時觸發的事件處理程式。

了解範例程式碼

重試事件處理程式

下載 OperationContextRetrying 映射失敗並設定為重試時，會呼叫事件處理程式。 如果達到應用程式中定義的重試次數上限，要求的 LocationMode 會變更為 SecondaryOnly。 此設定會強制應用程式嘗試從次要端點下載映像。 此設定可減少要求映像所需的時間，因為主要端點不會無限期重試。

private static void OperationContextRetrying(object sender, RequestEventArgs e)
{
    retryCount++;
    Console.WriteLine("Retrying event because of failure reading the primary. RetryCount = " + retryCount);

    // Check if we have had more than n retries in which case switch to secondary.
    if (retryCount >= retryThreshold)
    {

        // Check to see if we can fail over to secondary.
        if (blobClient.DefaultRequestOptions.LocationMode != LocationMode.SecondaryOnly)
        {
            blobClient.DefaultRequestOptions.LocationMode = LocationMode.SecondaryOnly;
            retryCount = 0;
        }
        else
        {
            throw new ApplicationException("Both primary and secondary are unreachable. Check your application's network connection. ");
        }
    }
}

要求已完成事件處理程式

OperationContextRequestCompleted成功下載映射時，會呼叫事件處理程式。 如果應用程式使用次要端點，應用程式會繼續使用此端點最多 20 次。 20 次之後，應用程式會將 LocationMode 設定回 PrimaryThenSecondary ，並重試主要端點。 如果要求成功，應用程式會繼續從主要端點讀取。

private static void OperationContextRequestCompleted(object sender, RequestEventArgs e)
{
    if (blobClient.DefaultRequestOptions.LocationMode == LocationMode.SecondaryOnly)
    {
        // You're reading the secondary. Let it read the secondary [secondaryThreshold] times,
        //    then switch back to the primary and see if it's available now.
        secondaryReadCount++;
        if (secondaryReadCount >= secondaryThreshold)
        {
            blobClient.DefaultRequestOptions.LocationMode = LocationMode.PrimaryThenSecondary;
            secondaryReadCount = 0;
        }
    }
}

將大量隨機數據上傳至 Azure 記憶體

線程數目下限和上限設定為 100，以確保允許大量的並行連線。

private static async Task UploadFilesAsync()
{
    // Create five randomly named containers to store the uploaded files.
    CloudBlobContainer[] containers = await GetRandomContainersAsync();

    var currentdir = System.IO.Directory.GetCurrentDirectory();

    // Path to the directory to upload
    string uploadPath = currentdir + "\\upload";

    // Start a timer to measure how long it takes to upload all the files.
    Stopwatch time = Stopwatch.StartNew();

    try
    {
        Console.WriteLine("Iterating in directory: {0}", uploadPath);

        int count = 0;
        int max_outstanding = 100;
        int completed_count = 0;

        // Define the BlobRequestOptions on the upload.
        // This includes defining an exponential retry policy to ensure that failed connections
        // are retried with a back off policy. As multiple large files are being uploaded using
        // large block sizes, this can cause an issue if an exponential retry policy is not defined.
        // Additionally, parallel operations are enabled with a thread count of 8.
        // This should be a multiple of the number of processor cores in the machine.
        // Lastly, MD5 hash validation is disabled for this example, improving the upload speed.
        BlobRequestOptions options = new BlobRequestOptions
        {
            ParallelOperationThreadCount = 8,
            DisableContentMD5Validation = true,
            StoreBlobContentMD5 = false
        };

        // Create a new instance of the SemaphoreSlim class to 
        // define the number of threads to use in the application.
        SemaphoreSlim sem = new SemaphoreSlim(max_outstanding, max_outstanding);

        List<Task> tasks = new List<Task>();
        Console.WriteLine("Found {0} file(s)", Directory.GetFiles(uploadPath).Count());

        // Iterate through the files
        foreach (string path in Directory.GetFiles(uploadPath))
        {
            var container = containers[count % 5];
            string fileName = Path.GetFileName(path);
            Console.WriteLine("Uploading {0} to container {1}", path, container.Name);
            CloudBlockBlob blockBlob = container.GetBlockBlobReference(fileName);

            // Set the block size to 100MB.
            blockBlob.StreamWriteSizeInBytes = 100 * 1024 * 1024;

            await sem.WaitAsync();

            // Create a task for each file to upload. The tasks are
            // added to a collection and all run asynchronously.
            tasks.Add(blockBlob.UploadFromFileAsync(path, null, options, null).ContinueWith((t) =>
            {
                sem.Release();
                Interlocked.Increment(ref completed_count);
            }));

            count++;
        }

        // Run all the tasks asynchronously.
        await Task.WhenAll(tasks);

        time.Stop();

        Console.WriteLine("Upload has been completed in {0} seconds. Press any key to continue", time.Elapsed.TotalSeconds.ToString());

        Console.ReadLine();
    }
    catch (DirectoryNotFoundException ex)
    {
        Console.WriteLine("Error parsing files in the directory: {0}", ex.Message);
    }
    catch (Exception ex)
    {
        Console.WriteLine(ex.Message);
    }
}

除了設定線程和連線限制設定之外，UploadFromStreamAsync 方法的 BlobRequestOptions 也會設定為使用平行處理原則並停用 MD5 哈希驗證。 檔案會以 100 MB 區塊上傳，此設定可提供更佳的效能，但如果使用效能不佳的網路，就好像重試整個 100 MB 區塊失敗一樣，可能會耗費成本。

財產 價值 說明
平行操作執行緒計數 8 此設定會在上傳時將 Blob 分成區塊。 為了達到最高效能，此值應該是核心數目的八倍。
停用內容MD5驗證 是 這個屬性會停用檢查已上傳內容的 MD5 哈希。 停用 MD5 驗證會產生更快的傳輸。 但不會確認正在傳輸之檔案的有效性或完整性。
StoreBlobContentMD5 假的 這個屬性會判斷 MD5 哈希是否計算並儲存在檔案中。
RetryPolicy 2 秒的退避，最多重試 10 次 決定要求的重試策略。 在此範例中，對於連線失敗會進行重試，指數重試 原則設定為 2 秒延遲，並且最大重試次數為 10 次。 當您的應用程式接近達到 Blob 記憶體的延展性目標時，此設定很重要。 如需詳細資訊，請參閱 Blob 儲存體的延展性和效能目標。

從 Azure 儲存體下載大量隨機資料

應用程式會讀取位於 storageconnectionstring 中所指定記憶體帳戶中的容器。 在容器中使用 ListBlobsSegmentedAsync 方法每次循環遍歷 10 個 Blob，並使用 DownloadToFileAsync 方法將它們下載到本機電腦。

下表顯示為每個 Blob 在下載時定義的 BlobRequestOptions。

財產 價值 說明
停用內容MD5驗證 是 這個屬性會停用檢查已上傳內容的 MD5 哈希。 停用 MD5 驗證會產生更快的傳輸。 但不會確認正在傳輸之檔案的有效性或完整性。
StoreBlobContentMD5 假的 這個屬性會判斷 MD5 哈希是否計算並儲存。 
private static async Task DownloadFilesAsync()
{
    CloudBlobClient blobClient = GetCloudBlobClient();

    // Define the BlobRequestOptions on the download, including disabling MD5 
    // hash validation for this example, this improves the download speed.
    BlobRequestOptions options = new BlobRequestOptions
    {
        DisableContentMD5Validation = true,
        StoreBlobContentMD5 = false
    };

    // Retrieve the list of containers in the storage account.
    // Create a directory and configure variables for use later.
    BlobContinuationToken continuationToken = null;
    List<CloudBlobContainer> containers = new List<CloudBlobContainer>();
    do
    {
        var listingResult = await blobClient.ListContainersSegmentedAsync(continuationToken);
        continuationToken = listingResult.ContinuationToken;
        containers.AddRange(listingResult.Results);
    }
    while (continuationToken != null);

    var directory = Directory.CreateDirectory("download");
    BlobResultSegment resultSegment = null;
    Stopwatch time = Stopwatch.StartNew();

    // Download the blobs
    try
    {
        List<Task> tasks = new List<Task>();
        int max_outstanding = 100;
        int completed_count = 0;

        // Create a new instance of the SemaphoreSlim class to
        // define the number of threads to use in the application.
        SemaphoreSlim sem = new SemaphoreSlim(max_outstanding, max_outstanding);

        // Iterate through the containers
        foreach (CloudBlobContainer container in containers)
        {
            do
            {
                // Return the blobs from the container, 10 at a time.
                resultSegment = await container.ListBlobsSegmentedAsync(null, true, BlobListingDetails.All, 10, continuationToken, null, null);
                continuationToken = resultSegment.ContinuationToken;
                {
                    foreach (var blobItem in resultSegment.Results)
                    {

                        if (((CloudBlob)blobItem).Properties.BlobType == BlobType.BlockBlob)
                        {
                            // Get the blob and add a task to download the blob asynchronously from the storage account.
                            CloudBlockBlob blockBlob = container.GetBlockBlobReference(((CloudBlockBlob)blobItem).Name);
                            Console.WriteLine("Downloading {0} from container {1}", blockBlob.Name, container.Name);
                            await sem.WaitAsync();
                            tasks.Add(blockBlob.DownloadToFileAsync(directory.FullName + "\\" + blockBlob.Name, FileMode.Create, null, options, null).ContinueWith((t) =>
                            {
                                sem.Release();
                                Interlocked.Increment(ref completed_count);
                            }));

                        }
                    }
                }
            }
            while (continuationToken != null);
        }

        // Creates an asynchronous task that completes when all the downloads complete.
        await Task.WhenAll(tasks);
    }
    catch (Exception e)
    {
        Console.WriteLine("\nError encountered during transfer: {0}", e.Message);
    }

    time.Stop();
    Console.WriteLine("Download has been completed in {0} seconds. Press any key to continue", time.Elapsed.TotalSeconds.ToString());
    Console.ReadLine();
}

啟用 Azure 記憶體分析記錄 （傳統）

程式代碼範例：

var storageAccount = CloudStorageAccount.Parse(connStr);  
var queueClient = storageAccount.CreateCloudQueueClient();  
var serviceProperties = queueClient.GetServiceProperties();

serviceProperties.Logging.LoggingOperations = LoggingOperations.All;  
serviceProperties.Logging.RetentionDays = 2;

queueClient.SetServiceProperties(serviceProperties);

修改記錄資料保留期間

下列範例會將 Blob 和 Queue 儲存服務的保留期間輸出到控制台。

var storageAccount = CloudStorageAccount.Parse(connectionString);

var blobClient = storageAccount.CreateCloudBlobClient();
var queueClient = storageAccount.CreateCloudQueueClient();

var blobserviceProperties = blobClient.GetServiceProperties();
var queueserviceProperties = queueClient.GetServiceProperties();

Console.WriteLine("Retention period for logs from the blob service is: " +
   blobserviceProperties.Logging.RetentionDays.ToString());

Console.WriteLine("Retention period for logs from the queue service is: " +
   queueserviceProperties.Logging.RetentionDays.ToString());

下列範例會將 Blob 和佇列記憶體服務的記錄保留期間變更為 4 天。


blobserviceProperties.Logging.RetentionDays = 4;
queueserviceProperties.Logging.RetentionDays = 4;

blobClient.SetServiceProperties(blobserviceProperties);
queueClient.SetServiceProperties(queueserviceProperties);

啟用 Azure 記憶體分析計量 （傳統）

程式代碼範例：

var storageAccount = CloudStorageAccount.Parse(connStr);  
var queueClient = storageAccount.CreateCloudQueueClient();  
var serviceProperties = queueClient.GetServiceProperties();

serviceProperties.HourMetrics.MetricsLevel = MetricsLevel.Service;  
serviceProperties.HourMetrics.RetentionDays = 10;

queueClient.SetServiceProperties(serviceProperties);

設定用戶端應用程式的傳輸層安全性 （TLS）

下列範例示範如何使用 Azure 記憶體用戶端連結庫 11.x 版，在 .NET 用戶端中啟用 TLS 1.2：

static void EnableTls12()
{
    // Enable TLS 1.2 before connecting to Azure Storage
    System.Net.ServicePointManager.SecurityProtocol = System.Net.SecurityProtocolType.Tls12;

    // Add your connection string here.
    string connectionString = "";

    // Connect to Azure Storage and create a new container.
    CloudStorageAccount storageAccount = CloudStorageAccount.Parse(connectionString);
    CloudBlobClient blobClient = storageAccount.CreateCloudBlobClient();

    CloudBlobContainer container = blobClient.GetContainerReference("sample-container");
    container.CreateIfNotExists();
}

Microsoft Azure 記憶體監視、診斷和疑難解答 （傳統）

如果儲存體用戶端程式庫在客戶端擲回 StorageException，則 RequestInformation 屬性包含一個包含 ServiceRequestID 屬性的 RequestResult 物件。 您也可以從 OperationContext 實例存取 RequestResult 物件。

下列程式代碼範例示範如何將 OperationContext 物件附加至對儲存服務的請求中，以設定自定義 ClientRequestId 值。 它也會示範如何從回應消息擷取 ServerRequestId 值。

//Parse the connection string for the storage account.
const string ConnectionString = "DefaultEndpointsProtocol=https;AccountName=account-name;AccountKey=account-key";
CloudStorageAccount storageAccount = CloudStorageAccount.Parse(ConnectionString);
CloudBlobClient blobClient = storageAccount.CreateCloudBlobClient();

// Create an Operation Context that includes custom ClientRequestId string based on constants defined within the application along with a Guid.
OperationContext oc = new OperationContext();
oc.ClientRequestID = String.Format("{0} {1} {2} {3}", HOSTNAME, APPNAME, USERID, Guid.NewGuid().ToString());

try
{
    CloudBlobContainer container = blobClient.GetContainerReference("democontainer");
    ICloudBlob blob = container.GetBlobReferenceFromServer("testImage.jpg", null, null, oc);  
    var downloadToPath = string.Format("./{0}", blob.Name);
    using (var fs = File.OpenWrite(downloadToPath))
    {
        blob.DownloadToStream(fs, null, null, oc);
        Console.WriteLine("\t Blob downloaded to file: {0}", downloadToPath);
    }
}
catch (StorageException storageException)
{
    Console.WriteLine("Storage exception {0} occurred", storageException.Message);
    // Multiple results may exist due to client side retry logic - each retried operation will have a unique ServiceRequestId
    foreach (var result in oc.RequestResults)
    {
            Console.WriteLine("HttpStatus: {0}, ServiceRequestId {1}", result.HttpStatusCode, result.ServiceRequestID);
    }
}

調查用戶端效能問題 - 停用 Nagle 演算法

程式代碼範例：

var storageAccount = CloudStorageAccount.Parse(connStr);
ServicePoint queueServicePoint = ServicePointManager.FindServicePoint(storageAccount.QueueEndpoint);
queueServicePoint.UseNagleAlgorithm = false;

調查網路等待時間問題 - 設定跨原始來源資源分享 （CORS）

程式代碼範例：

CloudBlobClient client = new CloudBlobClient(blobEndpoint, new StorageCredentials(accountName, accountKey));
// Set the service properties.
ServiceProperties sp = client.GetServiceProperties();
sp.DefaultServiceVersion = "2013-08-15";
CorsRule cr = new CorsRule();
cr.AllowedHeaders.Add("*");
cr.AllowedMethods = CorsHttpMethods.Get | CorsHttpMethods.Put;
cr.AllowedOrigins.Add("http://www.contoso.com");
cr.ExposedHeaders.Add("x-ms-*");
cr.MaxAgeInSeconds = 5;
sp.Cors.CorsRules.Clear();
sp.Cors.CorsRules.Add(cr);
client.SetServiceProperties(sp);

建立指定大小的空頁 Blob

為了建立分頁 Blob，我們會先建立 CloudBlobClient 物件，並使用基底 URI 來存取記憶體帳戶的 Blob 記憶體（圖 1 中的 pbaccount ），以及 StorageCredentialsAccountAndKey 物件，如下列範例所示。 接著，此範例會示範如何創建 CloudBlobContainer 物件的參考，並在容器（testvhds）尚未存在時創建該容器。 然後使用 CloudBlobContainer 物件，藉由指定要存取的分頁 Blob 名稱 （os4.vhd） 來建立 CloudPageBlob 物件的參考。 若要建立分頁 Blob，請呼叫 CloudPageBlob.Create，傳入要建立的 Blob 大小上限。 blobSize 必須是 512 個字節的倍數。

using Microsoft.Azure;
using Microsoft.Azure.Storage;
using Microsoft.Azure.Storage.Blob;

long OneGigabyteAsBytes = 1024 * 1024 * 1024;
// Retrieve storage account from connection string.
CloudStorageAccount storageAccount = CloudStorageAccount.Parse(
    CloudConfigurationManager.GetSetting("StorageConnectionString"));

// Create the blob client.
CloudBlobClient blobClient = storageAccount.CreateCloudBlobClient();

// Retrieve a reference to a container.
CloudBlobContainer container = blobClient.GetContainerReference("testvhds");

// Create the container if it doesn't already exist.
container.CreateIfNotExists();

CloudPageBlob pageBlob = container.GetPageBlobReference("os4.vhd");
pageBlob.Create(16 * OneGigabyteAsBytes);

調整頁面 Blob 大小

若要在建立之後重新調整分頁 Blob 的大小，請使用調整大小方法。 要求的大小應該是 512 位元組的倍數。

pageBlob.Resize(32 * OneGigabyteAsBytes);

將頁面寫入頁 Blob

若要寫入頁面，請使用 CloudPageBlob.WritePages 方法。

pageBlob.WritePages(dataStream, startingOffset);

從頁面 Blob 讀取頁面

若要讀取頁面，請使用 CloudPageBlob.DownloadRangeToByteArray 方法來讀取分頁 Blob 中的位元組範圍。

byte[] buffer = new byte[rangeSize];
pageBlob.DownloadRangeToByteArray(buffer, bufferOffset, pageBlobOffset, rangeSize);

若要判斷哪些頁面受數據支援，請使用 CloudPageBlob.GetPageRanges。 然後，您可以對傳回的範圍進行列舉，並下載每個範圍中的資料。

IEnumerable<PageRange> pageRanges = pageBlob.GetPageRanges();

foreach (PageRange range in pageRanges)
{
    // Calculate the range size
    int rangeSize = (int)(range.EndOffset + 1 - range.StartOffset);

    byte[] buffer = new byte[rangeSize];

    // Read from the correct starting offset in the page blob and
    // place the data in the bufferOffset of the buffer byte array
    pageBlob.DownloadRangeToByteArray(buffer, bufferOffset, range.StartOffset, rangeSize);

    // Then use the buffer for the page range just read
}
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