CODEWITHSUNDEEP
c#asp.net-coreblobazure-blob-storage
Yanayaya
Yanayaya

Reputation: 2184

How do I return an image to a view from a private Azure Blob Stroage account in ASP.NET Core?

I've set my Azure blob storage containers to private and I have a shared access key that I've defined within my asp.net core application. For jobs such as listing the contents of the blob storage, it works well but now I find myself needing to bring back an image file to show within my view. The problem is that when I return the blob, yes I can access it in the controller but it just returns the string to its location, accessing that location without the access key returns the error Resource not found, which is expected.

My question is, how do I return an image blob which requires the shared access key to my view? Here is my code so far which, only returns the Uri as a string which isn't any use for the above-mentioned reason. Do I need to download the image and store it temporarily or something?

CarController Usings

using Azure.Storage.Blobs;
using Azure.Storage.Blobs.Models;

CarController.cs

[HttpGet]
public IActionResult Edit(int id)
{
    var car = _carService.GetCar(id);

    string strContainerName = "uploads";    
    string filePrefix = "car/" + id + "/car-image.jpg";
    var filelist = new List<BlobListViewModel>();

    BlobServiceClient blobServiceClient = new BlobServiceClient(accessKey);
    BlobContainerClient containerClient = blobServiceClient.GetBlobContainerClient(strContainerName);

    //Get the specific image 
    var blob = containerClient.GetBlobClient(filePrefix);

    //I'm binding to a view model as a string, which, as I say, doesn't work for security reasons.
    var data = new BlobListViewModel {
        FileName = blob.Uri.ToString()
    };

        return View(data);
    }

Upvotes: 1

Views: 1395

Answers (1)

Gaurav Mantri
Gaurav Mantri

Reputation: 136334

To read from a private container, you would need to create a Shared Access Signature on either the blob or the blob container with at least Read permission.

Here's the code you can use. In this, I am creating a SAS Token on the blob with Read permission that will expire after 1 minute from the time it was created.

        BlobSasBuilder blobSasBuilder = new BlobSasBuilder()
        {
            BlobContainerName = strContainerName,
            BlobName = filePrefix,
            ExpiresOn = DateTime.UtcNow.AddMinutes(1),
        };
        blobSasBuilder.SetPermissions(BlobAccountSasPermissions.Read);
        var sasToken = blobSasBuilder.ToSasQueryParameters(new Azure.Storage.StorageSharedKeyCredential(accountName, accountKey)).ToString();
        var blob = containerClient.GetBlobClient(filePrefix);
        var blobSasUrl = blob.Uri.ToString() + "?" + sasToken;
        //I'm binding to a view model as a string, which, as I say, doesn't work for security reasons.
        var data = new BlobListViewModel
        {
            FileName = blobSasUrl
        };

Upvotes: 2

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