Storage

If your application requires an external repository for models, images, or other files, XRV offers a flexible file storage system. The base class, FileAccess, can be extended to create custom implementations with full CRUD capabilities for files in various storage repositories.

File Access

The following methods are available in any FileAccess implementation and provide core functionalities for file and directory operations.

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

The ApplicationDataFileAccess implementation sets the base path to System.Environment.SpecialFolder.LocalApplicationData, which varies depending on the platform. To use this storage, set the BaseDirectory to the desired folder name. This option is ideal for data caching or temporary file storage, but note that files may not be accessible outside of the application depending on the platform.

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

Note

Some folders are used internally. Avoid using "cache" as the base directory name.

Azure Blob Data Storage

Azure Blob Storage can also be used for storing and retrieving files needed by your application. To set up an Azure Blob instance, provide storage account configuration details. Note that directory methods may not work here, as Azure Blob Storage does not support traditional directories. When using SAS (Shared Access Signature), ensure it includes permissions for full CRUD access if needed.

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

Azure Files is another supported storage option that uses similar configuration parameters. You can set up Azure Files using the connection configuration data provided.

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 instance can use an optional disk cache, which will check for and retrieve files locally before attempting to download them again. To enable caching, create a DiskCache instance and assign it to the FileAccess instance.

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

Cache settings include the following options:

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