Xamarin text blob Azure storage - azure

Question

I am using Azure storage blob to store image and I am trying to display it in my Xamrin.form application. I have find a simple tutorial and the code on github.
I have succeed to implement it by following the steps and and create an account on azure storage blob.
The problem is : I can see the name of the file but not the "image"
here is the error:
read started: <Thread Pool> #9
[0:] HTTP Request: Could not retrieve https://xxxxxx.blob.core.windows.net/yyyy/kakashi.jpg, status code NotFound
[0:] ImageLoaderSourceHandler: Could not retrieve image or image data was invalid: Uri: https://lxxxxxx.blob.core.windows.net/yyyy/kakashi.jpg
Thread finished: <Thread Pool> #4
Here is the tutorial:
click to see
Here is the Github:
click to see
Here is the output on screen:
and I have this error when I put the Urlof the image (https://lxxxxxx.blob.core.windows.net/yyyy/kakashi.jpg
) on my bronwser:
This XML file does not appear to have any style information associated with it. The document tree is shown below.
<Error>
<Code>ResourceNotFound</Code>
<Message>
The specified resource does not exist. RequestId:97933c69-a01e-014f-6669-f0502e000000 Time:2018-05-20T18:33:28.4774584Z
</Message>
</Error>

Answer 1

The error means you don't set Public access level to Blob.
See this requirement in your tutorial.
Code you use requires this setting, because it accesses the blob directly using blob Uri.
See PhotosBlobStorageService.cs
return blobList.Select(x => new PhotoModel { Title = x.Name, Uri = x.Uri }).ToList();
If you do want to keep Private level, you have to make some changes to the statement above. Here's the reference.
return blobList.Select(x => new PhotoModel { Title = x.Name,
Uri = new Uri(x.Uri+x.GetSharedAccessSignature(
new SharedAccessBlobPolicy {
Permissions = SharedAccessBlobPermissions.Read|SharedAccessBlobPermissions.Write,
// you can modify the expiration to meet your requirement
SharedAccessExpiryTime = DateTime.UtcNow.AddYears(1)
} ))
}).ToList();
This change allows you to visit private blob with a SAS.

Answer 2

1.Please check your subscription first.
2.Check the access policy of your container.
3.Here is the steps to Save and get blobs through the code.
1)Using NuGet we can install required Assembly packages.
Go to "Manage Package for Solution Menu" and search for WindowsAzure.Storage and WindowsAzure.ConfigurationManager and click on install.
2)Get access keys in the configuration.
3)Sample code to Create blob through the code:
public async Task<string> SaveImagesToAzureBlob(HttpPostedFileBase imageToUpload)
{
try
{
CloudStorageAccount cloudStorageAccount = CloudStorageAccount.Parse(CloudConfigurationManager.GetSetting("StorageConnectionString"));
CloudBlobClient cloudBlobClient = cloudStorageAccount.CreateCloudBlobClient();
CloudBlobContainer cloudBlobContainer = cloudBlobClient.GetContainerReference("sampleimage");
if (await cloudBlobContainer.CreateIfNotExistsAsync())
{
await cloudBlobContainer.SetPermissionsAsync(
new BlobContainerPermissions
{
PublicAccess = BlobContainerPublicAccessType.Blob
}
);
}
string imageFullPath = null;
string imageName = Guid.NewGuid().ToString() + "-" + Path.GetExtension(imageToUpload.FileName);
CloudBlockBlob cloudBlockBlob = cloudBlobContainer.GetBlockBlobReference(imageName);
cloudBlockBlob.Properties.ContentType = imageToUpload.ContentType;
await cloudBlockBlob.UploadFromStreamAsync(imageToUpload.InputStream);
imageFullPath = cloudBlockBlob.Uri.ToString();
return imageFullPath;
}
catch (Exception ex)
{
throw ex;
}
}
Now, check your storage account, you can see the container sample generated.
By default, the container will be private, no one can access from outside. To set the permissions we should use the SetPermission method as below.
CloudBlobContainer .SetPermissions( new BlobContainerPermissions { PublicAccess = BlobContainerPublicAccessType.Blob });
Please try different permissions in the list.
Please note the permission level settings.In your case it may cause the issue.
For more details :
Reference
https://learn.microsoft.com/en-us/azure/azure-resource-manager/resource-manager-deployment-model
https://learn.microsoft.com/en-us/azure/storage/blobs/storage-dotnet-how-to-use-blobs