D365 FO操作FTP

D365 FO与.NET的交互比起AX2012 提高不止一个层次，AX2012与.NET交互只能算半成品,有些时候需要各种稀奇古怪的转换才能用。
D365 FO直接就编译成CIL了，使用.NET的类库也更加简洁。

通过FTP与其他系统做交互，可以直接通过.NET的System.NET类库，简单封装一下就可以用了。

using System.Net;
using System.IO;
using System.Text;

public class Ftp
{
    FtpWebRequest           request;
    FtpWebResponse          response;

    FTPAddress           address;
    FTPUserName          userName;
    FTPPassword          password;

    const   str FtpListFiles        = 'NLST';
    const   str FtpDownloadFile     = 'RETR';
    const   str FtpDeleteFile       = 'DELE';
    const   str FtpUploadFile       = 'STOR';

    public static Ftp construct(
        FTPAddress       _address,
        FTPUserName      _userName,
        FTPPassword      _password)
    {
        return new Ftp(
                        _address,
                        _userName,
                        _password);
    }

    /// <summary>
    /// 
    /// </summary>
    /// <param name = "_address">FTP的IP地址或域名，不带前缀FTP://</param>
    /// <param name = "_userName">访问FTP的用户名</param>
    /// <param name = "_password">访问FTP的密码</param>
    public void new(
        FTPAddress       _address,
        FTPUserName      _userName,
        FTPPassword      _password)
    {        
        address     = "FTP://" + _address;
        userName    = _userName;
        password    = _password;
    }

    public List getFiles()
    {
        List    files = new List(Types::String);
        
        this.initRequest(FtpListFiles);
        response = request.GetResponse();
        StreamReader sr = new StreamReader(response.GetResponseStream());
        
        while (!sr.EndOfStream)
        {
            files.addEnd(sr.ReadLine());
        }
        return files;
    }

    public void uploadFile(
            MemoryStream _ms,
            Encoding    _encoding,
            Filename    _fileName)
    {
        System.Byte[] bytes = _encoding.GetBytes(new StreamReader(_ms).ReadToEnd());

        this.initRequest(FtpUploadFile, _fileName);

        using(Stream stream = request.GetRequestStream())
        {
            stream.Write(bytes, 0, bytes.get_Length());
            stream.Close();
            response = request.GetResponse();

            if (response.StatusCode != FtpStatusCode::ClosingData)
            {
                throw  error(response.StatusDescription);
            }
            response.Close();
        }
    }

    public void deleteFile(Filename _fileName)
    {
        this.initRequest(FtpDeleteFile, _fileName);
        response = request.GetResponse();
    }

    public MemoryStream downloadFile(Filename _fileName)
    {
        MemoryStream ms = new MemoryStream();

        this.initRequest(FtpDownloadFile, _fileName);
        
        response = request.GetResponse();
        
        using (Stream stream = response.GetResponseStream())
        {
            int bufferSize = 2048;
            System.Byte[] buffer = new System.Byte[bufferSize]();
            int readCount = stream.Read(buffer, 0, bufferSize);
            while (readCount)
            {
                ms.Write(buffer, 0, readCount);
                readCount = stream.read(buffer, 0, bufferSize);
            }
        }
        response.Close();
        return ms;
    }

    private void initRequest(
        str         _method,
        Filename    _fileName = '')
    {
        request = WebRequest::Create(new System.Uri(_fileName ? address + "/" + _fileName : address));
                
        NetworkCredential credential = new NetworkCredential(userName, password);
        request.Credentials = credential;
        request.Method = _method;        
    }

}

上传文件
首先将数据写入到System.IO.MemoryStream类是实例中，然后调用FTP类的UploadFile方法就可以了。

ms.Position = 0;

        new FTP(
            exportGroupTable.FTPAddress, 
            exportGroupTable.FTPUserName, 
            exportGroupTable.FTPPassword).uploadFile(
                                            ms, 
                                            encoding, 
                                            fileName);

下载文件
跟上传类似，调用FTP的方法downloadFile

MemoryStream ms = ftp.downloadFile(_fileName);

如果要报文件存入到数据库里，只要用Binary类将得到ms转换成container类型，然后赋值给container类型的表字段就可以了。

Binary::constructFromMemoryStream(ms).getContainer();

Binary这个类用来做MemoeryStream和Container之间的转换很好用，如果把存到container类型字段的文件读取出来，可以用下面的方法。

ms = Binary::constructFromContainer(someTable.FileContent).getMemoryStream();

接下来就就可以用.NET的StreamReader之类的类库进行遍历分析了。