Azure BLOB Storage: Using the Storage Client Library

Introduction

Today, I will introduce Azure BLOB storage, a very simple and useful way to create a storage account and container, where we can maintain files (byte arrays and objects). There are basically these
following 4 basic hierarchies for Azure BLOB storage:

1. CloudStorageAccount: This is a reference to storage account (we will create a new sample storage account in this article).
2. CloudBlobClient: This reference to the object is used to perform operations on a BLOB storage account.
3. CloudBlobContainer: This is a reference to the container where the BLOB resides in.
4. CloudBlockBlob: This refer to actual BLOB.

When we write the code samples you will have the better understanding of these 4 points mentioned above.

First of all we will need to create a new storage account in Azure.

After creating a sample account we will get the storageaccount and sample key where we will create the container and put our BLOB. Now we will create a sample application for the BLOB storage.

Creating a Sample Application

Create a simple Console application, AzureStorageSample.

Then add a sample class library project.

Now add a WindowsAzure.storage Nuget package.

Now I am adding the following code to the TestAzureRespository class.

 

using System;
using System.Collections.Generic;
using System.Configuration;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using Microsoft.WindowsAzure.Storage;
using Microsoft.WindowsAzure.Storage.Blob;
namespace AzureBlobRepository
{
    public class TestAzureRespository
    {
        public CloudBlobClient BlobClient
        {
            get;
            set;
        }
        public CloudBlobContainer BlobContainer
        {
            get;
            set;
        }
        public TestAzureRespository()
        {       }
        private void GetContainer(string ContainerName)
        {
            var connectionString = ConfigurationManager.ConnectionStrings["connectionstring"].ConnectionString;
            var storageAccount = CloudStorageAccount.Parse(connectionString);
            BlobClient = storageAccount.CreateCloudBlobClient();
            // Retrieve a reference to a container.
            BlobContainer = BlobClient.GetContainerReference(ContainerName);
            // Create the container if it doesn't already exist.
            BlobContainer.CreateIfNotExists();
        }
        public string AddToBlobSTorage(string ContainerName, byte[] FileStream)
        {
            GetContainer(ContainerName);
            string blobName = Guid.NewGuid().ToString();
            CloudBlockBlob blockBlob = BlobContainer.GetBlockBlobReference(blobName);
            blockBlob.UploadFromByteArray(FileStream, 0, FileStream.Length);
            return blobName;
        }
        public string AddToBlobSTorage(string ContainerName, string Text)
        {
            GetContainer(ContainerName);
            string blobName = Guid.NewGuid().ToString();
            CloudBlockBlob blockBlob = BlobContainer.GetBlockBlobReference(blobName);
            blockBlob.UploadText(Text);
            return blobName;
        }
        public byte[] GetBytesFromBlobStorage(string ContainerName, string BlobName)
        {
            GetContainer(ContainerName);
            CloudBlockBlob blockBlob = BlobContainer.GetBlockBlobReference(BlobName);
            blockBlob.FetchAttributes();
            byte[] byteArray = new byte[blockBlob.Properties.Length];
            blockBlob.DownloadToByteArray(byteArray, 0);
            return byteArray;
        }
        public string GetStringFromBlobStorage(string ContainerName, string BlobName)
        {
            GetContainer(ContainerName);
            CloudBlockBlob blockBlob = BlobContainer.GetBlockBlobReference(BlobName);
            blockBlob.FetchAttributes();
            return blockBlob.DownloadText();
        }
    }
}

 

Where the connection string is set on the web config file like this:

 

<connectionStrings>
    <add name="connectionstring_name" connectionString="DefaultEndpointsProtocol=https;AccountName=your_azure_storage_account_name;AccountKey=your_azure_storage_account_key" />
</connectionStrings>

 

Now I will introducing the calling code as in the following:

 

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using AzureBlobRepository;
namespace AzureStorageSample
{
    class Program
    {
        static void Main(string[] args)
        {
            TestAzureRespository aurRepos = new TestAzureRespository();
            string test = "Hi Vivek This is only for test purpose";
            byte[] array = Encoding.ASCII.GetBytes(test);
            string guid1 = aurRepos.AddToBlobSTorage("Azure_Container_Name_1", array);
            string guid2 = aurRepos.AddToBlobSTorage("Azure_Container_Name_2", test);
            string getmesg = aurRepos.GetStringFromBlobStorage("Azure_Container_Name_2", guid2);
            Console.WriteLine(getmesg);
        }
    }
}

 

When running this code you will see the same string message when fetching from the BLOB.

For a better understanding, please follow the link:

How to use BLOB.