Developing Solutions for Azure (AZ-204)

Last Updated: 7/9/2024

Manage Blob Storage Using .NET

Create Azure Account

az login
az group create --location <myLocation> --name az204-blob-rg
az storage account create --resource-group az204-blob-rg --name <myStorageAcct> --location <myLocation> --sku Standard_LRS

Copy Connection String

  • Navigate to the Azure portal.
  • Locate the storage account created.
  • Select Access keys in the Security + networking section of the navigation pane. Here, you can view your account access keys and the complete connection string for each key.
  • Find the Connection string value under key1, and select the Copy button to copy the connection string. You will add the connection string value to the code in the next section.

Create Project in VS Code

  • Create project
dotnet new console -n az204-blob
cd az204-blob
dotnet build
mkdir data
dotnet add package Azure.Storage.Blobs
  • Add code in program.cs
using Azure.Storage.Blobs;
using Azure.Storage.Blobs.Models;

Console.WriteLine("Azure Blob Storage exercise\n");

// Run the examples asynchronously, wait for the results before proceeding
ProcessAsync().GetAwaiter().GetResult();

Console.WriteLine("Press enter to exit the sample application.");
Console.ReadLine();

static async Task ProcessAsync()
{
    // Copy the connection string from the portal in the variable below.
    string storageConnectionString = "CONNECTION STRING";

    // Create a client that can authenticate with a connection string
    BlobServiceClient blobServiceClient = new BlobServiceClient(storageConnectionString);

    // COPY EXAMPLE CODE BELOW HERE
}
  • Set the storageConnectionString variable to the value you copied from the portal.

Create a container

//Create a unique name for the container
string containerName = "wtblob" + Guid.NewGuid().ToString();

// Create the container and return a container client object
BlobContainerClient containerClient = await blobServiceClient.CreateBlobContainerAsync(containerName);
Console.WriteLine("A container named '" + containerName + "' has been created. " +
    "\nTake a minute and verify in the portal." + 
    "\nNext a file will be created and uploaded to the container.");
Console.WriteLine("Press 'Enter' to continue.");
Console.ReadLine();

Upload blob

// Create a local file in the ./data/ directory for uploading and downloading
string localPath = "./data/";
string fileName = "wtfile" + Guid.NewGuid().ToString() + ".txt";
string localFilePath = Path.Combine(localPath, fileName);

// Write text to the file
await File.WriteAllTextAsync(localFilePath, "Hello, World!");

// Get a reference to the blob
BlobClient blobClient = containerClient.GetBlobClient(fileName);

Console.WriteLine("Uploading to Blob storage as blob:\n\t {0}\n", blobClient.Uri);

// Open the file and upload its data
using (FileStream uploadFileStream = File.OpenRead(localFilePath))
    {
await blobClient.UploadAsync(uploadFileStream);
uploadFileStream.Close();
    }

Console.WriteLine("\nThe file was uploaded. We'll verify by listing" + 
        " the blobs next.");
Console.WriteLine("Press 'Enter' to continue.");
Console.ReadLine();

List blobs

// List blobs in the container
Console.WriteLine("Listing blobs...");
await foreach (BlobItem blobItem in containerClient.GetBlobsAsync())
{
    Console.WriteLine("\t" + blobItem.Name);
}

Console.WriteLine("\nYou can also verify by looking inside the " + 
        "container in the portal." +
        "\nNext the blob will be downloaded with an altered file name.");
Console.WriteLine("Press 'Enter' to continue.");
Console.ReadLine();

Download blobs

// Download the blob to a local file
// Append the string "DOWNLOADED" before the .txt extension 
string downloadFilePath = localFilePath.Replace(".txt", "DOWNLOADED.txt");

Console.WriteLine("\nDownloading blob to\n\t{0}\n", downloadFilePath);

// Download the blob's contents and save it to a file
BlobDownloadInfo download = await blobClient.DownloadAsync();

using (FileStream downloadFileStream = File.OpenWrite(downloadFilePath))
{
    await download.Content.CopyToAsync(downloadFileStream);
}
Console.WriteLine("\nLocate the local file in the data directory created earlier to verify it was downloaded.");
Console.WriteLine("The next step is to delete the container and local files.");
Console.WriteLine("Press 'Enter' to continue.");
Console.ReadLine();

Delete Container

// Delete the container and clean up local files created
Console.WriteLine("\n\nDeleting blob container...");
await containerClient.DeleteAsync();

Console.WriteLine("Deleting the local source and downloaded files...");
File.Delete(localFilePath);
File.Delete(downloadFilePath);

Console.WriteLine("Finished cleaning up.");

Run code

dotnet build
dotnet run

Cleanup

az group delete --name az204-blob-rg --no-wait
Previous
Next