Custom-File-Id-Provider.md

TusDiskStore uses file id providers upon creating files to generate valid file ids. The default file id provider is GuidFileIdProvider but you can use a different file id provider by passing it to the constructor of TusDiskStore. tusdotnet is shipped with the following file id providers:

• GuidFileIdProvider generates GUIDs (example id: def1853a4a72464eb8b0d357c4f6e8a5, using guildFormat = "n")
• Base64FileIdProvider: generates base64 ids (example id: KjJA5IoF2Bdi58B7KK5pRw, using byteLength = 16)

Tip: If you want to generate file ids similar to youtubes video ids, use Base64FileIdProvider(byteLength: 8). This will generate file ids that look like this: xQs3c615q5M

If you want more control over the generated ids, you can create your own file id provider using the ITusFileIdProvider interface.

For example you can use your database as a file id provider:

public class DatabaseFileIdProvider : tusdotnet.Interfaces.ITusFileIdProvider
{
    private readonly ApplicationDbContext _db;

    /// <summary>
    /// Creates a new DatabaseFileIdProvider
    /// </summary>
    public DatabaseFileIdProvider(ApplicationDbContext db)
    {
        _db = db;
    }

    /// <inheritdoc />
    public async Task<string> CreateId(string metadata)
    {
        FileEntity file = new FileEntity();
        _db.Files.Add(file);
        await _db.Files.SaveChangesAsync();
        return file.Id;
    }

    /// <inheritdoc />
    public async Task<bool> ValidateId(string fileId)
    {
        return _db.Files.ExistsAsync(fileId);
    }
}

Or you can inherit from another file id provider and just add your own implementation:

public class DatabaseGuidProvider : tusdotnet.Stores.FileIdProviders.GuidFileIdProvider
{
    private readonly ApplicationDbContext _db;

    /// <summary>
    /// Creates a new DatabaseFileIdProvider
    /// </summary>
    public DatabaseGuidProvider(ApplicationDbContext db) : base()
    {
        _db = db;
    }

    /// <inheritdoc />
    public override async Task<string> CreateId(string metadata)
    {
        FileEntity file = new FileEntity();
        file.Id = base.CreateId();

        _db.Files.Add(file);
        await _db.Files.SaveChangesAsync();
        return file.Id;
    }

    /// <inheritdoc />
    public override async Task<bool> ValidateId(string fileId)
    {
        return await base.ValidateId(fileId) && await _db.Files.ExistsAsync(fileId);
    }
}