Getting ready

This recipe assumes the following is in the application configuration file:

<appSettings>
   <add key="DataConnectionString"value="DefaultEndpointsProtocol=https;AccountName={ACCOUNT_NAME};AccountKey={ACCOUNT_KEY}"/>
</appSettings>

We must replace {ACCOUNT_NAME} and {ACCOUNT_KEY} with appropriate values for the account name and access key.

How to do it...

We are going to specify various levels of public access control for a container. We do this as follows:

How it works...

In steps 1 and 2, we set up the class.

In step 3, we add a method that creates a container and blob, and applies a public access policy to the container. We create a CloudBlobClient instance from the data connection string in the configuration file. We then create a new container using the name passed in to the method. Then, we create a BlobContainerPermissions instance with the BlobContainerPublicAccessType passed into the method and set the permissions on the container. Note that we must create the container before we set the permissions because SetPermissions() sets the permissions directly on the container. Finally, we create a blob in the container.

In step 4, we use an HttpWebRequest instance to retrieve the blob without providing any authentication. This request causes a 404 (Not Found) error when the request attempts to retrieve a blob that has not been configured for public access. Note that when constructing blobUri for the storage emulator, we must add a / into the path after cloudStorageAccount.BlobEndpoint because of a difference in the way the Storage Client library constructs the endpoint for the storage emulator and the storage service. For example, we need to use the following for the storage emulator:

Uri blobUri = new Uri(cloudStorageAccount.BlobEndpoint + "/" +containerName + "/" + blobName);

In step 5, we add a method that invokes the CreateContainerAndSetPermission() method once for each value of the BlobContainerPublicAccessType enumeration. We then invoke the method twice, to retrieve blobs from different container. The second invocation leads to a 404 error since container3 has not been configured for unauthenticated public access.

See also