前情提要
筆者所處環境為金融業，所在的科別屬寫週邊的應用系統，開發的每個系統多多少少都需要與別的系統串接，常見的有核心、外匯、通路科等等。如[DotnetCore]Socket程式實作那篇所提，因為通常核心系統環境比較特殊，相對應的串接方式，偏Socket或者交換檔案這類的傳統型居多。這篇主要以FTP交換檔案為主介紹其作法，筆者會再寫兩篇相關的文章，請拭目以待。
內容
安裝FluentFTP套件
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| dotnet add package FluentFTP
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定義相關Model
FTP相關Config
筆者這邊把ftp相關的設定定義成一個ConfigModel，以強型別的方式存取設定值
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| public class FTPConfigBaseModel
{
public string Server { get; set; }
public string Account { get; set; }
public string Password { get; set; }
public string RemotePath { get; set; }
public string LocalPath { get; set; }
}
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FTP上傳統一結構
筆者這邊因為大部分上傳檔案，用意在於跟別的系統交換檔案，檔案內容由資料庫內容運算而得，筆者所在環境又屬於那種崇尚寫Store Procedure，因此不要讓需求太發散，索性定一個統一的結構，是回傳ftp上傳使用的資料則統一使用該資料結構
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| public class FileUploadResponseModel
{
public string FileName { get; set; }
public string Encoding { get; set; }
public string DataStr { get; set; }
}
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撰寫Service
宣告IFtpService
筆者這邊使用dotnet core預設的Dependency Injection，就注到底了
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| public interface IFtpService
{
void DownloadData(FTPConfigBaseModel downloadFtpInfo, List<string> fileList);
void UploadData(FTPConfigBaseModel uploadFtpInfo, List<FileUploadResponseModel> fileUploadResponseModels);
bool IsExist(FTPConfigBaseModel uploadFtpInfo, string filename);
}
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實作FTPService
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| public class FtpService : IFtpService
{
private readonly ILoggerManager _logger;
private readonly IFilePathService _filePathService;
private readonly IConfiguration _config;
public FtpService(IFilePathService filePathService
, IConfiguration config, ILoggerManager logger)
{
_filePathService = filePathService;
_config = config;
_logger = logger;
}
public void DownloadData(FTPConfigBaseModel downloadFtpInfo, List<string> fileList)
{
var localDir = _filePathService.GetDirectoryPath(downloadFtpInfo.LocalPath);
var remoteDir = downloadFtpInfo.RemotePath;
FtpClient client = new FtpClient(downloadFtpInfo.Server);
var password = Encoding.UTF8.GetString(Convert.FromBase64String(downloadFtpInfo.Password));
var securePwd = PasswordExtension.SecureStringToString(
PasswordExtension.GetPasswordSecurity(password));
try
{
client.Credentials = new NetworkCredential(downloadFtpInfo.Account, securePwd);
client.Connect();
foreach (var item in fileList)
{
var localPath = Path.Combine(localDir, item);
var remotePath = Path.Combine(remoteDir, item);
if (client.FileExists(remotePath))
{
client.DownloadFile(localPath, remotePath);
}
}
}
catch (Exception exception)
{
throw exception;
}
finally
{
client.Disconnect();
}
}
public void UploadData(FTPConfigBaseModel uploadFtpInfo, List<FileUploadResponseModel> fileUploadResponseModels)
{
var localDir = _filePathService.GetDirectoryPath(uploadFtpInfo.LocalPath);
var remoteDir = uploadFtpInfo.RemotePath;
var fileGroupList = fileUploadResponseModels.GroupBy(x => x.FileName).ToList();
var fileList = new List<string>();
foreach (var item in fileGroupList)
{
var fileContent = item.Select(x => x.DataStr)
.Aggregate((x, y) => $"{x}\r\n{y}");
var encoding = item.FirstOrDefault()?.Encoding;
File.WriteAllText(Path.Combine(localDir, item.Key)
, fileContent, Encoding.GetEncoding(encoding));
fileList.Add(item.Key);
}
FtpClient client = new FtpClient(uploadFtpInfo.Server);
var password = Encoding.UTF8.GetString(Convert.FromBase64String(uploadFtpInfo.Password));
var securePwd = PasswordExtension.SecureStringToString(
PasswordExtension.GetPasswordSecurity(password));
try
{
client.Credentials = new NetworkCredential(uploadFtpInfo.Account, securePwd);
client.Connect();
foreach (var item in fileList)
{
var localPath = Path.Combine(localDir, item);
var remotePath = Path.Combine(remoteDir, item);
client.UploadFile(localPath, remotePath, FtpRemoteExists.Overwrite);
}
}
catch (Exception exception)
{
throw exception;
}
finally
{
client.Disconnect();
}
}
public bool IsExist(FTPConfigBaseModel uploadFtpInfo, string filename)
{
FtpClient client = new FtpClient(uploadFtpInfo.Server);
var password = Encoding.UTF8.GetString(Convert.FromBase64String(uploadFtpInfo.Password));
var securePwd = PasswordExtension.SecureStringToString(
PasswordExtension.GetPasswordSecurity(password));
try
{
client.Credentials = new NetworkCredential(uploadFtpInfo.Account, securePwd);
client.Connect();
var remotePath = Path.Combine(uploadFtpInfo.RemotePath, filename);
return client.FileExists(remotePath);
}
catch (Exception exception)
{
throw exception;
}
finally
{
client.Disconnect();
}
}
}
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其中IFilePathService及PasswordExtension，筆者會再寫一篇，說來話長，筆者這邊環境需要產出源掃報告才可允許上線，源掃軟體使用Fortify，只要跟System.IO.Path時需要再額外加入判斷才算安全，只要是密碼類型的需要透過SecureString處理過才算安全，因此筆者這邊就索性抽出IFilePathService及PasswordExtension，大家都靠這幾個共用的Service做存取伺服器內部檔案及處理密碼字串。
Client端使用
Startup.cs中宣告
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| services.AddTransient<IFtpService, FtpService>();
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終端Service中引用
筆者這邊就不另外示範了，主要是將IFtpService從建構值注入就可以使用了，再則可以透過IConfiguration(若將ftp相關資訊設定於appsettings中)的方式讀取出FTP相關設定，製作成FtpConfigBaseModel的格式，傳進IFtpService中即可呼叫下載、上傳與判斷是否存在。
結論
筆者之前工作都很少透過程式碼存取Ftp，既然這裡有存取需求，實作並記錄一下，成就感十足阿，FluentFTP簡單易用，果然名字上有Fluent都特別好用。