generate sas token for azure blob
Azure.Storage.Sas.BlobSasBuilder blobSasBuilder = new Azure.Storage.Sas.BlobSasBuilder()
{
BlobContainerName = "demo-copy",
BlobName = "test.txt",
ExpiresOn = DateTime.UtcNow.AddMinutes(5),//Let SAS token expire after 5 minutes.
};
blobSasBuilder.SetPermissions(Azure.Storage.Sas.BlobSasPermissions.Read);//User will only be able to read the blob and it's properties
var sasToken = blobSasBuilder.ToSasQueryParameters(new StorageSharedKeyCredential(accountName, accountKey)).ToString();
var sasUrl = blobClient.Uri.AbsoluteUri + "?" + sasToken;