AnimeAnnouncer/AnimeAnnouncer.Torrents/TransmissionService.cs

using Transmission.API.RPC;
using Transmission.API.RPC.Arguments;
using Transmission.API.RPC.Entity;

namespace AnimeAnnouncer.Torrents
{
    /// <summary>
    /// Thin wrapper around the Transmission RPC client for adding torrents to the server.
    /// </summary>
    public class TransmissionService
    {
        public Client Client { get; }

        private TransmissionService(Client client)
        {
            Client = client;
        }

        /// <summary>
        /// Creates a client and verifies the server is reachable by requesting session information.
        /// Throws <see cref="InvalidOperationException"/> if the server doesn't respond with a valid session.
        /// </summary>
        public static async Task<TransmissionService> ConnectAsync(String host, String? username, String? password)
        {
            var client = new Client(host, null, username, password);
            var sessionInformation = await client.GetSessionInformationAsync();
            if (sessionInformation == null || String.IsNullOrEmpty(sessionInformation.Version))
                throw new InvalidOperationException($"An error occurred while receiving session information from the rpc server at {host}");

            return new TransmissionService(client);
        }

        /// <summary>
        /// Adds a .torrent file to the server, saving to <paramref name="saveLocation"/>, and applies a seed ratio limit.
        /// </summary>
        public async Task<NewTorrentInfo> AddNewTorrentFileToServerAsync(byte[] torrentFileData, String saveLocation, bool paused = true, double seedRatioLimit = 1.0)
        {
            NewTorrent newTorrent = new()
            {
                DownloadDirectory = saveLocation,
                Paused = paused,
                Metainfo = Convert.ToBase64String(torrentFileData)
            };
            var torrentInfo = await Client.TorrentAddAsync(newTorrent);
            var seedSettings = new TorrentSettings()
            {
                SeedRatioLimit = seedRatioLimit,
                SeedRatioMode = 1,
                IDs = [torrentInfo.ID]
            };

            // TorrentSetAsync returns void in Transmission.API.RPC 2.1.2, so it can't be awaited
            Client.TorrentSet(seedSettings);
            return torrentInfo;
        }
    }
}