Storage

If you need an external repository to load your models, images, or other types of files required by your application, you can take a look at what XRV offers regarding file storage. The base class for storage systems is the FileAccess class, which can be extended to create specific implementations for full CRUD access to files in a repository or folder.

File Access

We provide a set of implementations for FileAccess that we will enumerate. The following set of methods will be available when using any file access instance from code.

Method	Description
ClearAsync	Clears all files and directories.
CreateBaseDirectoryIfNotExistsAsync	Ensures that the base directory defined by BaseDirectory exists. If it does not exist, the directory is created.
CreateDirectoryAsync	Creates a directory, indicated by a relative path.
DeleteDirectoryAsync	Deletes a directory, indicated by a relative path.
DeleteFileAsync	Deletes a file, indicated by a relative path.
GetFileAsync	Gets file contents by relative path.
GetFileItemAsync	Gets file metadata by relative path.
EnumerateDirectoriesAsync	Enumerates directories existing in the base directory or a relative directory path.
EnumerateFilesAsync	Enumerates files existing in the base directory or a relative directory path.
ExistsDirectoryAsync	Checks if a directory, indicated by a relative path, exists or not.
WriteFileAsync	Writes file contents by relative path.

Local Application Data Folder Storage

This is implemented by ApplicationDataFileAccess, which sets the base path to the value of System.Environment.SpecialFolder.LocalApplicationData, which can change depending on the target platform. If you create a new file access instance of this type, just set the BaseDirectory value to a name for a base directory for that instance. You can use this file access as a data cache or to create temporary files needed by your application. However, these files may not be externally available depending on the target platform.

var fileAccess = new ApplicationDataFileAccess()
{
    BaseDirectory = "my-folder",
};

Note

We use some folders internally, so be careful and do not use "cache" as the base directory name.

Azure Blob Data Storage

You can also use Azure Blob Storage as a data source to download files required by your application. The only thing you need to do is add some storage account configuration settings when instantiating a file access of this type. You may find different static methods to create instances, depending on the set of configuration data you want to provide.

Please note that some directory methods may not work for this file access, as Azure Blob Storage does not have the concept of directories. When using SAS, remember that you should add appropriate permissions to the token if you want full CRUD access to blobs.

var fileAccess = AzureBlobFileAccess.CreateFromConnectionString("Storage account connection string", "Container name"); //or
var fileAccess = AzureBlobFileAccess.CreateFromUri("https://<ACCOUNT>.blob.core.windows.net/container?sv=2021-08-06&st=2022-11-18T15%3A07%3A20Z&..."); // Container URI containing SAS (or without SAS for public containers, if you need read-only operations)
var fileAccess = AzureBlobFileAccess.CreateFromConnectionString("https://<ACCOUNT>.blob.core.windows.net/container", "sv=2021-08-06&st=2022-11-18T15%3A07%3A20Z&...");  // Container URI with separated SAS

Azure Files Data Storage

We also support another service, Azure Files, that you can use. Similarly, you need to specify connection configuration data. You may find different static methods to create instances, depending on the set of configuration data you want to provide.

var fileAccess = AzureFileShareFileAccess.CreateFromConnectionString("Storage account connection string", "Share name"); //or
var fileAccess = AzureFileShareFileAccess.CreateFromUri("https://<ACCOUNT>.file.core.windows.net/share?sv=2021-08-06&st=2022-11-18T15%3A07%3A20Z&..."); // Share URI containing SAS
var fileAccess = AzureFileShareFileAccess.CreateFromConnectionString("https://<ACCOUNT>.file.core.windows.net/share", "sv=2021-08-06&st=2022-11-18T15%3A07%3A20Z&...");  // Share URI with separated SAS

Disk Cache

Any FileAccess can use an optional cache, which will check for files locally instead of downloading them again. To activate caching for a file access, just create an instance of DiskCache and assign it.

var fileAccess = AzureFileShareFileAccess.CreateFromUri(...);
fileAccess.Cache = new DiskCache("images"); // indicate a unique cache name for your needs

For caching, you can specify the following settings.

Property	Description
SizeLimit	Cache size limit. Defaults to 100 MB.
SlidingExpiration	Maximum time an item remains in cache without being accessed.