FluentFTP库实现FTP文件操作的类

使用FluentFTP库实现FTP文件操作的类，包括删除文件、判断文件是否存在、读取文件、保存文件等操作。类中的方法都是异步的，使用了await和async关键字.

public interface IFileStore : IDisposable
	{
		Task SaveAsync(string filefullname, Stream fileStream, bool isOverwrite = true);

		Task ReadAsync(string filefullname);

		Task DeleteAsync(string filefullname);

		Task ExistsAsync(string filefullname);
	}

 /// 

    /// ftp操作类
    /// 
    public class FTPFileStore : IFileStore, IDisposable
    {
        private readonly ISession _Session;
        private readonly ILogger _logger;

        public FTPFileStore(ISession Session, ILogger logger)
        {
            _Session = Session;
            _logger = logger;
        }

        private string GetFtpPath(string filefullName)
        {
            if (string.IsNullOrEmpty(filefullName))
            {
                throw new ArgumentNullException(nameof(filefullName));
            }
            if (filefullName.StartsWith("/"))
            {
                return $"/TID{_Session.GetTenantId()}/{filefullName}";
            }
            return $"/TID{_Session.GetTenantId()}{filefullName}";
        }

        private async Task GetFtpClientAsync()
        {
            var host = MSEApplication.GetConfigValue("FTP:Host").Trim();
            var port = int.TryParse(MSEApplication.GetConfigValue("FTP:Port"), out var ftpPort) ? ftpPort : 21;
            var userName = (MSEApplication.GetConfigValue("FTP:UserName") ?? string.Empty).Trim();
            var password = (MSEApplication.GetConfigValue("FTP:Password") ?? string.Empty).Trim();

            var ftpClient = new FtpClient(host, port, userName, password)
            {
                DataConnectionConnectTimeout = (int)TimeSpan.FromMinutes(2).TotalMilliseconds,
                DataConnectionReadTimeout = (int)TimeSpan.FromMinutes(2).TotalMilliseconds,
                ConnectTimeout = (int)TimeSpan.FromSeconds(30).TotalMilliseconds,
                ReadTimeout = (int)TimeSpan.FromSeconds(30).TotalMilliseconds
            };
            if (!ftpClient.IsConnected)
            {
                await ftpClient.ConnectAsync();
            }
            return ftpClient;
        }

        public async Task DeleteAsync(string filefullName)
        {
            try
            {
                filefullName = GetFtpPath(filefullName);
                using (var ftpClient = await GetFtpClientAsync())
                {
                    await ftpClient.DeleteFileAsync(filefullName);
                }
            }
            catch (Exception ex)
            {
                _logger.Error($"删除文件异常", ex);
                throw;
            }
        }

        public async Task ExistsAsync(string filefullName)
        {
            try
            {
                filefullName = GetFtpPath(filefullName);
                using (var ftpClient = await GetFtpClientAsync())
                {
                    return await ftpClient.FileExistsAsync(filefullName);
                }
            }
            catch (Exception ex)
            {
                _logger.Error($"文件是否存在异常", ex);
                throw;
            }
        }

        public async Task ReadAsync(string filefullName)
        {
            try
            {
                filefullName = GetFtpPath(filefullName);
                using (var ftpClient = await GetFtpClientAsync())
                {
                    var ms = new MemoryStream();
                    await ftpClient.DownloadStreamAsync(ms, filefullName);
                    ms.Position = 0L;
                    return ms;
                }
            }
            catch (Exception ex)
            {
                _logger.Error($"文件加载异常", ex);
                throw new BusinessException("文件加载异常!");
            }
        }

        public async Task SaveAsync(string filefullName, Stream fileStream, bool isOverwrite = true)
        {
            var sw = new Stopwatch();
            sw.Start();
            string ftpPath = GetFtpPath(filefullName);
            try
            {
                fileStream.Position = 0L;
                using (var ftpClient = await GetFtpClientAsync())
                {
                    if ((await ftpClient.UploadStreamAsync(fileStream, ftpPath, FtpRemoteExists.Overwrite, createRemoteDir: true)) != FtpStatus.Success)
                    {
                        throw new BusinessException("文件保存失败!");
                    }
                }
                return filefullName;
            }
            catch (Exception ex)
            {
                _logger.Error("文件保存异常", ex);
                throw;
            }
            finally
            {
                sw.Stop();
                if (sw.ElapsedMilliseconds > 1000)
                {
                    _logger.Debug("FTP上传文件：{filefullName}。时间：{sw.ElapsedMilliseconds}ms");
                }
            }
        }
        public void Dispose()
        {
            // no-op
        }
    }