Storage

If you need an external repository to load your models, images or other type of files, that are required by your application, you can take a look to what XRV offers about files storage. Base class for storage systems is FileAccess class, that can be extended to create specific implementations for a full CRUD access to files in a repository or folder.

File access

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

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

Local application data folder storage

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

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

Note

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

Azure Blobs data storage

You can also use Azure Blob Storage as data source to download files required by your application. Only thing you need is to add some storage account configuration settings when instancing a file access of this type. You may find different static methods to create instances, depending on 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 directory. When using SAS, remember that you should add appropiate 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 have support for other service, Azure Files that you can use. In the same way, you need to specify connection configuration data to make. You may find different static methods to create instances, depending on 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, that 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 an unique cache name for your needs

For cache, you can specify following settings.

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