public async Task <string[]> DownloadAsync(int siteId, SFtpOptions options = null)
{
var policy = PolicyFactory.CreateRetry(5, (e) =>
{
_logger.LogError($"Retrying, ex: {e}.");
});
var files = await policy.Execute(async() => await DoDownloadAsync(siteId, options));
if (files?.Length > 0)
{
return(files);
}
_logger.LogWarning($"No files found from sftp server.");
return(null);
}
private async Task <string[]> DoDownloadAsync(int siteId, SFtpOptions options)
{
var opts = _options.Value ?? options;
if (!opts.IsValid())
{
_logger.LogError($"{nameof(SFtpOptions)} is invalid, config: {opts}.");
return(null);
}
if (siteId <= 0)
{
_logger.LogError($"The {nameof(siteId)}[{siteId}] must be provided.");
return(null);
}
if (Interlocked.CompareExchange(ref _isDownloading, 1, 0) != 0)
{
_logger.LogWarning($"{nameof(SFTPFilesDownloader)} is downloading, please try again later.");
return(null);
}
string[] files = null;
try
{
var sftp = new Sftp();
_logger.LogInformation($"Connecting sftp server[{opts.Host}]...");
if (string.IsNullOrEmpty(opts.Host))
{
_logger.LogError($"The {nameof(opts.Host)}[{opts.Host}] must be provided.");
return(null);
}
await sftp.ConnectAsync(opts.Host, 22);
_logger.LogInformation($"Authenticating sftp user[UserName: {opts.UserName}]...");
switch (opts.AuthScheme)
{
case SFtpOptions.AuthenticateScheme.Password:
if (string.IsNullOrEmpty(opts.Password))
{
_logger.LogError($"In the password authenticate scheme, the password must be provided.");
return(null);
}
await sftp.AuthenticateAsync(opts.UserName, opts.Password);
break;
case SFtpOptions.AuthenticateScheme.SecurityKey:
if (opts.PrivateKey == null ||
!opts.PrivateKey.CanRead)
{
_logger.LogError($"In the security sey authenticate scheme, the Private Key must be provided.");
return(null);
}
var privateKey = new SecureShellPrivateKey(opts.PrivateKey);
await sftp.AuthenticateAsync(opts.UserName, privateKey);
break;
default:
throw new InvalidOperationException($"Only these authenticate schemes[{nameof(SFtpOptions.AuthenticateScheme.Password)},{nameof(SFtpOptions.AuthenticateScheme.SecurityKey)}] supported.");
}
var filter = _namingStrategy.GetFileRegexName();
files = await sftp.ListNameAsync(opts.RemoteDirectory, new NameRegexSearchCondition(filter));
if (files.Length <= 0)
{
_logger.LogWarning($"No reports files found from sftp server.");
return(null);
}
_logger.LogInformation($"The reports[{files.Aggregate((x, y) => $"{x},{y}")}] will be downloaded.");
if (string.IsNullOrEmpty(opts.LocalDirectory))
{
opts.LocalDirectory = Path.Combine(Directory.GetCurrentDirectory(), "reports", siteId.ToString());
}
if (!Directory.Exists(opts.LocalDirectory))
{
Directory.CreateDirectory(opts.LocalDirectory);
}
var hasNewFile = false;
foreach (var file in files)
{
var isDownloaded = await _manager.IsDownloadedAsync(siteId, opts.LocalDirectory, file);
if (isDownloaded)
{
continue;
}
_logger.LogInformation($"The file[{file}] downloading...");
var localPath = Path.Combine(opts.LocalDirectory, file);
if (File.Exists(localPath))
{
File.Delete(localPath);
}
using (var stream = new FileStream(localPath, FileMode.Create))
{
var remoteDir = opts.RemoteDirectory.TrimStart('/').TrimEnd('/').Replace('\\', '/');
var remotePath = $"/{remoteDir}/{file}";
await sftp.DownloadFileAsync(remotePath, stream);
}
hasNewFile = true;
_logger.LogInformation($"The file[{localPath}] was downloaded successfully.");
}
await sftp.DisconnectAsync();
if (hasNewFile)
{
_manager.TryRefreshSavePoint(siteId);
}
return(files.Select(it => Path.Combine(opts.LocalDirectory, it)).ToArray());
}
catch (Exception e)
{
var filesToRemove = files?.Select(it => Path.Combine(opts.LocalDirectory, it)).ToArray();
_manager.TryRemoveSavePoint(siteId, filesToRemove);
_logger.LogError($"{nameof(DownloadAsync)} has a unknown exception, ex: {e}");
return(null);
}
finally
{
_isDownloading = 0;
}
}