WORKING WITH CLOUD QUEUE AND BLOB STORAGE in Visual C#.NET

Drawer ECC200 in Visual C#.NET WORKING WITH CLOUD QUEUE AND BLOB STORAGE

public class AzureStorageFacade { protected StorageAccountInfo _accountInformation; protected int retry = 1; protected int retryInterval = 1000; public StorageAccountInfo StorageAccountInfo { get{ return _accountInformation; } } public AzureStorageFacade() { _InitializationStorages(); } protected void _InitializationStorages() { retry = Convert.ToInt32(ConfigurationManager.AppSettings["Retry"]); retryInterval = Convert.ToInt32(ConfigurationManager.AppSettings["RetryInterval"]); _accountInformation = StorageAccountInfo.GetDefaultBlobStorageAccountFromConfiguration(); } } } Listing 3-16 shows the implementation of the blob facade class, which encapsulates all blob storage access functions and attributes of blob storage needed for a client application in a more comprehensive manner than in the implementation in the previous exercise. Listing 3-16. Implementation of the BlobStorageFacade Class Derived from the AzureStorageFacade Class using using using using using using using using System; System.Collections.Generic; System.Linq; System.Text; System.Configuration; System.Collections.Specialized; System.Threading; System.IO;

namespace AzureForDotNetDevelopers.LargeDataToBlob.CloudStorage.BlobStorage { using Microsoft.ServiceHosting.ServiceRuntime; using Microsoft.Samples.ServiceHosting.StorageClient; using CSharpBuildingBlocks;

public class BlobStorageFacade : AzureStorageFacade { static public long LARGE_BLOB_SIZE = 2 * 1024 * 1024;// 2 MB protected BlobStorage _blobStorage; protected BlobContainer _blobContainer; protected string _blobContainerName = ConfigurationManager.AppSettings["BlobContainerName"]; protected NameValueCollection _metadata = null; protected Thread _createBlobWorkerthread = null; public BlobContents Contents { get; set; } public BlobProperties Properties { get; set; } public bool Overwrite { get; set; } public BlobStorageFacade() { _blobStorage = BlobStorage.Create(_accountInformation); _blobStorage.RetryPolicy = RetryPolicies.RetryN(retry, TimeSpan.FromMilliseconds(retryInterval)); _blobContainer = _blobStorage.GetBlobContainer(_blobContainerName); } public BlobStorageFacade(NameValueCollection metadata):this() { _metadata = metadata; _blobContainer.CreateContainer(_metadata, ContainerAccessControl.Private); } public BlobStorageFacade(BlobContents blobContents, BlobProperties blobProperties, bool overwrite) : this(blobProperties.Metadata) { Contents = blobContents; Properties = blobProperties; Overwrite = overwrite; } public BlobContainer BlobContainer { get { return _blobContainer; } } public IEnumerable<BlobContainer> GetBlobContainers() { return _blobStorage.ListBlobContainers(); } public void CreateBlob() { _blobContainer.CreateBlob(Properties, Contents,

Overwrite); } public void DeleteBlob() { if (_blobContainer.DoesBlobExist(Properties.Name)) { _blobContainer.DeleteBlob(Properties.Name); } } } } As mentioned before, we use a background worker thread and ICommand design pattern in this application. The base class implementation for these two classes comes from my existing building block collection library. The reference assemblies are called CSharpBuildingBlocks and CSharpBuildingBlocks.QueuedBackgroundWorker. These two assemblies come with the source code download and will be used several places in other chapters. Listing 3-17 and Listing 3-18 are the implementation for CreateBlobStatus and DeleteBlobStatus. A worker thread is created at the time a message arrives for either creating or deleting a blob request. Two member functions are used to handle create or delete activities accordingly. The algorithms for progress are different in these two classes. For blob creation, the percentage of the creation progress is determined by comparing the size of the blob to be created against the actual size of the data that has been committed to cloud blob storage. No incremented progress can be reported to the client application, because the detailed information of a newly created or deleted blob will not be updated until the transactions have been committed on the server. Listing 3-17. The CreateBlobStatus Class Derived from the BlobStorageAction Class using using using using using using using System; System.Collections.Generic; System.Linq; System.Text; System.Configuration; System.Collections.Specialized; System.Threading; AzureForDotNetDevelopers.LargeDataToBlob.CloudStorage.BlobStorage Microsoft.ServiceHosting.ServiceRuntime; Microsoft.Samples.ServiceHosting.StorageClient; CSharpBuildingBlocks;

public class CreateBlobStatus : BlobStorageActionStatus, ICommand { public long CreateContentSize { get; set; } public CreateBlobStatus(BlobContents blobContents, BlobProperties blobProperties,

bool overwrite) : base(blobContents, blobProperties, overwrite) { } public void Execute() { try { if (_blobStorageFacade.BlobContainer .DoesBlobExist(_blobStorageFacade.Properties.Name)) { var blob = (from m in _blobStorageFacade.BlobContainer.ListBlobs(string.Empty, false) where (m as BlobProperties).Name == _blobStorageFacade.Properties.Name select m as BlobProperties).Single<BlobProperties>(); _percentComplete = (float)(((blob as BlobProperties).ContentLength * 100.0) / (CreateContentSize * 1.0)); System.Diagnostics.Trace.WriteLine( string.Format( "---{0}:Execute, _percentComplete = <{1}>", this.ToString(), _percentComplete ) ); } } catch (Exception ex) { System.Diagnostics.Trace.WriteLine( string.Format( "---{0}:Execute,exception caught <{1}>", this.ToString(), ex.Message ) ); } } override protected void _blobStorageWorkerThread(object paramters) { try {

(paramters as BlobStorageFacade).CreateBlob(); } catch { } } } } Listing 3-18. The DeleteBlobStatus Class Derived from the BlobStorageAction Class using using using using using System; System.Collections.Generic; System.Linq; System.Text; System.Threading; AzureForDotNetDevelopers.LargeDataToBlob.CloudStorage.BlobStorage Microsoft.ServiceHosting.ServiceRuntime; Microsoft.Samples.ServiceHosting.StorageClient; CSharpBuildingBlocks;