C#.NETでFTPダウンロードを実装する方法

C#.NETでFTPダウンロードを実装する方法について説明する。

ここで説明する内容は、前回のVB.NETでFTPダウンロードを実装する方法のC#.NET版である。
基本的な実装方法はVB.NETと同様なので詳しい説明は割愛する。

VB.NET版と異なる点は、FTPに関するコードの記述をクラス化(clsFtpクラス)しているということで、フォームに入力された内容をclsFtpクラスのプロパティに設定してからfncGetFileForFtpプロシージャを実行している。

以下がそのサンプルコード(抜粋)である。

------------------------------------------------------------

namespace TestFtp
{
    public partial class frmMain : Form
    {

        private void btnConnect_Click(object sender, EventArgs e)
        {
            //＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊
            //接続ボタン押下時の処理
            //＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊

            //Ftpクラスの生成
            clsFtp clsFtp = new clsFtp();
            //各種ユーザ入力情報の取得
            clsFtp.FireWallServer = txtFireWallServer.Text.Trim();
            clsFtp.FireWallUser = txtFireWallUser.Text.Trim();
            clsFtp.FireWallPassword = txtFireWallPassword.Text.Trim();
            clsFtp.HostProxy = txtHostProxy.Text.Trim();
            clsFtp.HostServer = txtHostServer.Text.Trim();
            clsFtp.HostUser = txtHostUser.Text.Trim();
            clsFtp.HostPassword = txtHostPassword.Text.Trim();
            clsFtp.HostPath = txtHostPath.Text.Trim();
            clsFtp.HostFile = txtHostFile.Text.Trim();
            clsFtp.ClientPath = txtClientPath.Text.Trim();
            clsFtp.ClientFile = txtClientFile.Text.Trim();
            //ログ出力先を設定
            clsFtp.Log = txtLog;

            //指定ファイルをFTPでサーバより取得
            clsPublic clsPublic = new clsPublic();
            if (clsFtp.fncGetFileForFtp() == false)
            {
                clsPublic.fncMessagePut("ファイルの取得に失敗しました。", MessageBoxButtons.OK, MessageBoxIcon.Exclamation);
            }
            else
            {
                clsPublic.fncMessagePut("ファイルの取得が完了しました。", MessageBoxButtons.OK, MessageBoxIcon.Information);
            }
        }
    }
}

 

using System;
using System.Text;
using System.Net;
using System.Net.Sockets;
using System.Windows.Forms;

namespace TestFtp
{
    class clsFtp
    {
        private string strFireWallServer;
        private string strFireWallUser;
        private string strFireWallPassword;
        private string strHostProxy;
        private string strHostServer;
        private string strHostUser;
        private string strHostPassword;
        private string strHostPath;
        private string strHostFile;
        private string strClientPath;
        private string strClientFile;

        private TextBox txtLog;

        private Socket socClient;
        private System.IO.FileStream fsData;
        private Encoding encASC = new ASCIIEncoding();
        private Encoding encU8 = new UTF8Encoding();

        public string FireWallServer
        {
            get { return strFireWallServer; }
            set { strFireWallServer = value; }
        }
        public string FireWallUser
        {
            get { return strFireWallUser; }
            set { strFireWallUser = value; }
        }
        public string FireWallPassword
        {
            get { return strFireWallPassword; }
            set { strFireWallPassword = value; }
        }
        public string HostProxy
        {
            get { return strHostProxy; }
            set { strHostProxy = value; }
        }
        public string HostServer
        {
            get { return strHostServer; }
            set { strHostServer = value; }
        }
        public string HostUser
        {
            get { return strHostUser; }
            set { strHostUser = value; }
        }
        public string HostPassword
        {
            get { return strHostPassword; }
            set { strHostPassword = value; }
        }
        public string HostPath
        {
            get { return strHostPath; }
            set { strHostPath = value; }
        }
        public string HostFile
        {
            get { return strHostFile; }
            set { strHostFile = value; }
        }
        public string ClientPath
        {
            get { return strClientPath; }
            set { strClientPath = value; }
        }
        public string ClientFile
        {
            get { return strClientFile; }
            set { strClientFile = value; }
        }
        public TextBox Log
        {
            get { return txtLog; }
            set { txtLog = value; }
        }
        public Socket Client
        {
            get { return socClient; }
            set { socClient = value; }
        }

        public Boolean fncGetFileForFtp()
        {
            //＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊
            //FTPで指定サーバより指定ファイルをダウンロード
            //
            //   戻り値         :   True:正常、False:異常
            //
            //＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊

            Boolean blnReturn;
            Boolean blnConnect = false;

            try
            {
                txtLog.Clear();
                //ソケットオブジェクトの生成
                Client = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
                //FireWallサーバの接続先とポートを生成
                IPEndPoint iepFwIp = new IPEndPoint(Dns.GetHostEntry(FireWallServer).AddressList[0], 21);
                //FireWallサーバに接続
                Client.Connect(iepFwIp);
                //FireWallにログイン
                if (fncSendCommand("USER " + FireWallUser) == false)
                {
                    blnReturn = false;
                    goto Fin;
                }
                blnConnect = true;
                if (fncSendCommand("PASS " + FireWallPassword, FireWallPassword) == false)
                {
                    blnReturn = false;
                    goto Fin;
                }
                //サーバにログイン
                if (fncSendCommand("USER " + HostUser + "@" + HostServer + "@" + HostProxy) == false)
                {
                    blnReturn = false;
                    goto Fin;
                }
                if (fncSendCommand("PASS " + HostPassword, HostPassword) == false)
                {
                    blnReturn = false;
                    goto Fin;
                }
                //転送モードをASCIIに設定
                if (fncSendCommand("TYPE A") == false)
                {
                    blnReturn = false;
                    goto Fin;
                }
                //クライアントのIPアドレスと受信ポートを設定
                IPAddress ipaMyIp = Dns.GetHostAddresses(Dns.GetHostName())[1];
                TcpListener tlnData = new TcpListener(ipaMyIp, 0);
                tlnData.Start();
                int intMyPort = (int)((IPEndPoint)tlnData.LocalEndpoint).Port;

                //送受信ポートを設定
                if (fncSendCommand("PORT " + ipaMyIp.ToString().Replace(".", ",") + "," + (intMyPort / 256) + "," + (intMyPort % 256)) == false)
                {
                    blnReturn = false;
                    goto Fin;
                }
                //ダウンロードを要求するファイルを送信
                if (fncSendCommand("RETR " + HostPath + "/" + HostFile) == false)
                {
                    blnReturn = false;
                    goto Fin;
                }

                //ファイルをダウンロード
                Socket socData = tlnData.AcceptSocket();
                fsData = new System.IO.FileStream(System.IO.Path.Combine(ClientPath, ClientFile),
                    System.IO.FileMode.Create, System.IO.FileAccess.Write);
                byte[] bytBuffer = new byte[1023];
                DateTime datStart = DateTime.Now;
                while(true)
                {
                    int intSize=socData.Receive(bytBuffer);
                    if (intSize == 0)
                    { break; }
                    fsData.Write(bytBuffer, 0, intSize);
                }
                TimeSpan tsSpan = DateTime.Now - datStart;
                if (fncReceiveData() == false)
                {
                    blnReturn = false;
                    goto Fin;
                }
                string strMsg = "ダウンロードは正常に終了しました。 (" + Math.Ceiling(tsSpan.TotalSeconds) + "SEC. " +
                    (int)(fsData.Length / Math.Ceiling(tsSpan.TotalSeconds)) + "B/S)";
                subPutLog(strMsg);
                fsData.Close();
                socData.Close();

                blnReturn = true;
            }
            catch(Exception ex)
            {
                clsPublic clsPublic = new clsPublic();
                clsPublic.fncMessagePut(ex.Message, MessageBoxButtons.OK, MessageBoxIcon.Exclamation);
                blnReturn = false;
            }
            finally
            {
                if (blnConnect == true)
                {
                    if (fsData != null)
                    {
                        //出力ファイルを閉じる
                        fsData.Close();
                    }
                    //接続を閉じる
                    fncSendCommand("QUIT");
                    Client.Shutdown(SocketShutdown.Both);
                    Client.Close();
                }
                Client.Dispose();
                Client = null;
            }

            Fin:

            return blnReturn;
        }

        private Boolean fncReceiveData()
        {
            //＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊
            //サーバから応答メッセージを取得
            //
            //   戻り値          :   True:正常、False:異常
            //
            //＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊

            Boolean blnReturn;
            byte[] bytData = new byte[255];
            int intLen;
            string strData;

            try
            {
                while(Client.Available>0)
                {
                    //サーバからの応答を受信
                    intLen=Client.Receive(bytData);
                    //受信したメッセージのバイト列を文字列に変換
                    strData = encU8.GetString(bytData, 0, intLen);
                    subPutLog(strData);
                    System.Threading.Thread.Sleep(250);
                }

                blnReturn = true;

            }
            catch (Exception ex)
            {
                clsPublic clsPublic = new clsPublic();
                clsPublic.fncMessagePut(ex.Message, MessageBoxButtons.OK, MessageBoxIcon.Exclamation);
                blnReturn = false;
            }

            return blnReturn;
        }

        private Boolean fncSendCommand(string pCommand,string pPassword = "")
        {
            //＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊
            //サーバにコマンドを送信
            //
            //   pCommand        :   送信コマンド文字列
            //   pPassword       :   パスワード文字列
            //
            //   戻り値          :   True:正常、False:異常
            //
            //＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊

            Boolean blnReturn;

            try
            {
                //ログを出力
                pCommand = pCommand + "\r\n";
                subPutLog(">" + pCommand, pPassword);
                //送信するコマンドをASCIIのバイト列に変換
                byte[] bytCommand = encASC.GetBytes(pCommand);

                //コマンドを送信
                Client.Send(bytCommand, bytCommand.Length, SocketFlags.None);
                System.Threading.Thread.Sleep(250);

                //サーバからの応答を受信
                if (fncReceiveData() == false)
                {
                    blnReturn = false;
                }
                else
                {
                    blnReturn = true;
                }
            }
            catch(Exception ex)
            {
                clsPublic clsPublic = new clsPublic();
                clsPublic.fncMessagePut(ex.Message, MessageBoxButtons.OK, MessageBoxIcon.Exclamation);
                blnReturn = false;
            }

            return blnReturn;
        }

        private void subPutLog(string pMsg,string pPassword = "")
        {
            //＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊
            //ログを出力
            //
            //   pMsg            :   メッセージ文字列
            //   pPassword       :   パスワード文字列
            //
            //＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊

            if (txtLog.Text != "" && txtLog.Text.Substring(txtLog.TextLength - 2) != "\r\n")
            {
                txtLog.AppendText("\r\n");
            }
            if (pPassword != string.Empty)
            {
                pMsg=pMsg.Replace(pPassword,"[" + new string('X',pPassword.Length) + "]");
            }
            txtLog.AppendText(pMsg);
            Application.DoEvents();
        }
    }
}

------------------------------------------------------------

 

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