如何在C＃Web Api中流式傳輸文件以進行數據庫存儲

Question

我花了好幾個小時來處理許多發現的例子，但是沒有成功，因為在Web表單應用程序中超級簡單。 也就是說，上傳一個或多個文件並將它們存儲在sql server中。

在網絡表單（vb.net）中，我可以這樣做：

Dim fs As Stream = fileUpload1.PostedFile.InputStream
        Dim br As New BinaryReader(fs)
        Dim bytes As Byte() = br.ReadBytes(fs.Length)

        'insert the file into database
        Dim strQuery As String = "INSERT INTO files ([name], [type], [file]) VALUES (@Name, @ContentType, @Data)"
        Dim cmd As New SqlCommand(strQuery)

        cmd.Parameters.Add("@Name", SqlDbType.VarChar).Value = filename
        cmd.Parameters.Add("@ContentType", SqlDbType.VarChar).Value() = contenttype
        cmd.Parameters.Add("@Data", SqlDbType.Binary).Value = bytes

然后做數據庫執行語句......完成！

現在C＃Web-Api：

我現在通過Web-Api將上傳保存到文件系統的看似很好的例子是：

public Task<IEnumerable<FileDesc>> Old()
    {
        string folderName = "uploads";
        string PATH = HttpContext.Current.Server.MapPath("~/" + folderName);
        string rootUrl = Request.RequestUri.AbsoluteUri.Replace(Request.RequestUri.AbsolutePath, String.Empty);

        if (Request.Content.IsMimeMultipartContent())
        {
            var streamProvider = new MultipartFormDataStreamProvider(PATH);
            var task = Request.Content.ReadAsMultipartAsync(streamProvider).ContinueWith<IEnumerable<FileDesc>>(t =>
            {
                if (t.IsFaulted || t.IsCanceled)
                {
                    throw new HttpResponseException(HttpStatusCode.InternalServerError); 
                }
                var fileInfo = streamProvider.FileData.Select(i =>
                {
                    var info = new FileInfo(i.LocalFileName);
                    return new FileDesc(info.Name, rootUrl + "/" + folderName + "/" + info.Name, info.Length / 1024);
                });
                return fileInfo;
            });
            return task;
        }
        else
        {
            throw new HttpResponseException(Request.CreateResponse(HttpStatusCode.NotAcceptable, "This request is not properly formatted"));
        }
    }

我似乎無法弄清楚如何獲取每個多部分文件內容流，以便我可以發送到數據庫。 我看過帖子談論MultipartMemoryStreamProvider和MultipartStreamProvider，但我還沒弄清楚如何使用它們。 作為C＃和Web-Api的新手，我顯然已經超出了我的頭腦。

任何人都可以指導我如何將文件內容放入流中我可以獲取要發送到數據庫的字節嗎？

Answer 1

當我遇到這個問題時，這是我的解決方案：

客戶：

 public async Task UploadImage(byte[] image, string url)
        {
            Stream stream = new System.IO.MemoryStream(image);
            HttpStreamContent streamContent = new HttpStreamContent(stream.AsInputStream());

            Uri resourceAddress = null;
            Uri.TryCreate(url.Trim(), UriKind.Absolute, out resourceAddress);
            Windows.Web.Http.HttpRequestMessage request = new Windows.Web.Http.HttpRequestMessage(Windows.Web.Http.HttpMethod.Post, resourceAddress);
            request.Content = streamContent;

            var httpClient = new Windows.Web.Http.HttpClient();
            var cts = new CancellationTokenSource();
            Windows.Web.Http.HttpResponseMessage response = await httpClient.SendRequestAsync(request).AsTask(cts.Token);
        }

控制器：

public async Task<HttpResponseMessage> Post()
{
    Stream requestStream = await this.Request.Content.ReadAsStreamAsync();
    byte[] byteArray = null;
    using (MemoryStream ms = new MemoryStream())
    {
        await requestStream.CopyToAsync(ms);
        byteArray = ms.ToArray();
    }
    .
    .
    .
    return Request.CreateResponse(HttpStatusCode.OK);
}