DEV Community: Chandra Mohan Jha

Get blob from azure using Azure.Storage.Blobs

Chandra Mohan Jha — Wed, 21 Jul 2021 07:27:07 +0000

We can store blobs in Azure platform in C# using Azure.Storage.Blobs. In this article, we will fetch the blobs without downloading as a file.

First thing first: install NuGet package

Install NuGet package Azure.Storage.Blobs.

Import library

using Azure.Storage.Blobs;

Get connection string

I assume you have Azure account and thus connection string to connect to Azure Blob Storage. Store this in a variable or constant based on your need.

const string CONN_STRING = <connection_string_from_azure_portal>
const string BLOB_CONTAINER = <blob_container_name>

Now the final thing

We will fetch the blob and read it.

string filePath = "<optional_path/file_name.extension>";
var blobClient = new BlobClient(CONN_STRING, BLOB_CONTAINER, filePath);
using (var result = await blobClient.OpenReadAsync())
{
  byte[] content = new byte[result.Length];
  result.Read(content, 0, (int)result.Length);
  var jsonContent = System.Text.Encoding.Default.GetString(content);
  // Do whatever you want to do with this content
}

That's it. I hope it would be helpful to you. 🙂

Get all blobs in given Azure container

Chandra Mohan Jha — Fri, 26 Mar 2021 12:49:12 +0000

In last article, we tried to download single blob file from azure storage using Azure.Storage.Blobs. This is the new library developed by Microsoft to replace depercated Microsoft.WindowsAzure.Storage. So let's get started.

0. Setting up the context

In this article, we will try to get all the blobs(images) stored on Azure blob storage in defined format i.e. User_id/image.ext.

john_doe/image1.jpg
john_doe/profile.png
jane_doe/profile.PNG

So if there are blobs with given name in Azue, we are trying to get all blobs for user id john_doe

1. Install NuGet package

Install NuGet package Azure.Storage.Blobs. At the time of writing this, the latest version is 12.8.0.

2. Import library

using Azure.Storage.Blobs;

3. Get connection string

I assume you have Azure account and thus connection string to connect to Azure Blob Storage. Store this in a variable or constant based on your need.

const string CONN_STRING = <connection_string_from_azure_portal>
const string BLOB_CONTAINER = <blob_container_name>

-1. Now the final thing

I will list all blobs(images) present in given container and have specified format.

string userId = "john_doe";
var allBlobs = container.GetBlobs(prefix: $"{userId}");

The above code will fetch all the blobs details present in container with given prefix(john_doe).

If you want to download the blobs as well, this article might be helpful.

That's it. I hope this will be helpful. 🙂

Download blob from azure using Azure.Storage.Blobs

Chandra Mohan Jha — Tue, 23 Mar 2021 10:41:02 +0000

We can store blobs in Azure platform in C# using Azure.Storage.Blobs. Previously we had Microsoft.WindowsAzure.Storage for this but they rewrote it. Don't ask me why. As Microsoft.WindowsAzure.Storage is deprecated now and we needed to access Azure to read blobs, we have no other option rather than using new Azure.Storage.Blobs. If you search docs to use Azure in C#, the results will be flooded with Microsoft.WindowsAzure.Storage. If you ask specifically about new APIs, you will get mostly Microsoft docs links. I find Microsoft docs unusable🤭. And if you are like me, you are welcome to follow the article.

First thing first: install NuGet package

Install NuGet package Azure.Storage.Blobs. At the time of writing this, the latest version is 12.8.0.

Import library

using Azure.Storage.Blobs;

Get connection string

I assume you have Azure account and thus connection string to connect to Azure Blob Storage. Store this in a variable or constant based on your need.

const string CONN_STRING = <connection_string_from_azure_portal>
const string BLOB_CONTAINER = <blob_container_name>

Now the final thing

I will download the blob to a local file and read it.

string filePath = "<optional_path/file_name.extension>";
var blobClient = new BlobClient(CONN_STRING, BLOB_CONTAINER, <blob_uri>);
var result =  blobClient.DownloadTo(filePath); // file is downloaded
// check file download was success or not
if (result.Status == 206 || result.Status == 200)
{
  // You would be knowing this by now
  using (StreamReader r = new StreamReader(filePath))
  {
    string content = r.ReadToEnd(); // I don't know what you want to do with this
  }
}

That's it. I hope it would be helpful to you. 🙂