c# - Microsoft.ProjectOxford.Face。来自 FTP 的 AddFaceToLargeFaceListAsync 与 MemoryStream

Question

我正在使用 Microsoft FaceAPI 的 WS。使用 FileStream 时一切正常，但我必须从 FTP 读取图像，所以我使用的是 MemoryStream。我总是以这个例外结束：

{Microsoft.ProjectOxford.Face.FaceAPIException: Image size is too small.(InvalidImageSize)

这是我创建 MemoryStream 的方法。这是对的吗？？

 public MemoryStream GetFileStream(string filePath, string userName, string password)
    {

        Console.WriteLine($"getting file stream : {filePath}");
        MemoryStream ftpStream = null;
        try
        {
            var fileName = Guid.NewGuid().ToString();

            FtpWebRequest request = WebRequest.Create(filePath) as FtpWebRequest;
            request.Method = WebRequestMethods.Ftp.DownloadFile;
            request.Credentials = new NetworkCredential(userName, password);

            ftpStream = new MemoryStream();
            WebResponse response = request.GetResponse();
            Stream responseStream = response.GetResponseStream();

            byte[] buffer = new byte[1024];
            int bytesRead;
            while ((bytesRead = responseStream.Read(buffer, 0, buffer.Length)) > 0)
            {
                ftpStream.Write(buffer, 0, bytesRead);
            }
            responseStream.Close();

        }
        catch (Exception ex)
        {
            Console.WriteLine($"getting file stream : {filePath} " + ex.ToString());
        }
        return ftpStream;

    }

这是我调用 FaceAPI 的 WS 的任务

  using (MemoryStream fStream = ftpService.GetFileStream(imgPath, customerConfig.FTPUserName, customerConfig.FTPPassword))
                        {
                            try
                            {
                                if (fStream != null)
                                {
                                    Console.WriteLine("fStream Length : " + imgPath + " {" + fStream.Length + "}");
                                    var faces = await faceServiceClient.AddFaceToLargeFaceListAsync(listId, fStream); //==>> GET ME The EXCEPTION
                                    if (fStream != null)
                                    {
                                        fStream.Close();
                                    }
                                    if (urlFaceID.ContainsKey(imgPath) == false)
                                        urlFaceID.Add(imgPath, faces.PersistedFaceId.ToString());
                                }

                            }
                            catch (FaceAPIException ex)
                            {

                                if (ex.ErrorCode.Equals("ConcurrentOperationConflict"))
                                {
                                    imageList.Add(imgPath);

                                }

                                else if (ex.ErrorCode.Equals("RateLimitExceeded"))
                                {
                                    imageList.Add(imgPath);
                                }
                                else if (ex.ErrorMessage.Contains("more than 1 face in the image."))
                                {
                                    Console.WriteLine("more than 1 face in the image.");
                                }
                                if (InvalidUrlFaceID.ContainsKey(imgPath) == false)
                                {
                                    InvalidUrlFaceID.Add(imgPath, null);
                                }

                            }
                            finally
                            {
                                if (fStream != null)
                                {
                                    fStream.Close();
                                }
                            }
                        }

我不知道我是否正确阅读了 MemoryStream。找不到任何解决方案，我希望有人能回答。谢谢你们

谢谢

Answer 1

它看起来大部分是正确的，但是您忘记了读取和写入指针MemoryStream在您写入时都是提前的。换句话说，GetFileStream如您所写，返回的值已经指向流的末尾。您需要更改的只是在返回之前“倒回”流。

public MemoryStream GetFileStream(string filePath, string userName, string password)
{
    Console.WriteLine($"getting file stream : {filePath}");
    MemoryStream ftpStream = null;
    try
    {
        var fileName = Guid.NewGuid().ToString();

        FtpWebRequest request = WebRequest.Create(filePath) as FtpWebRequest;
        request.Method = WebRequestMethods.Ftp.DownloadFile;
        request.Credentials = new NetworkCredential(userName, password);

        ftpStream = new MemoryStream();
        ...
        ftpStream.Position = 0; // <-- ADD THIS LINE
    }
    catch (Exception ex)
    {
        Console.WriteLine($"getting file stream : {filePath} " + ex.ToString());
    }

    return ftpStream;
}