c# – 将文件上传到服务器会丢失内存异常

我正在尝试使用asp.net web api实现一个文件上传系统,我遇到了一个问题.我正在尝试将多部分表单数据写入内存流,因此可以根据服务层实现将其写入磁盘或Blob存储.问题是小文件可以正常工作,但是我正在尝试上传一个291 MB的文件,并且会丢失内存异常.这是代码：

if (!Request.Content.IsMimeMultipartContent())
        {
            Request.CreateErrorResponse(HttpStatusCode.UnsupportedMediaType,"Request must be multipart.");
        }

        var provider = new MultipartMemoryStreamProvider();

        try
        {
            await Request.Content.ReadAsMultipartAsync(provider);

            var infoPart = provider.Contents.Where(x => x.Headers.Contentdisposition.Name.Replace("\"",string.Empty) == "fileInfo").SingleOrDefault();
            var filePart = provider.Contents.Where(x => x.Headers.Contentdisposition.Name.Replace("\"",string.Empty) == "filePart" && x.Headers.Contentdisposition.FileName != null).Single();
            byte[] file = null;

            using (Stream stream = filePart.ReadAsstreamAsync().Result)
            {
                using (MemoryStream memory = new MemoryStream())
                {
                    stream.copyTo(memory);
                    file = memory.ToArray();
                }
            }

            string fileContentType = filePart.Headers.ContentType.MediaType;

            FileDto result = _fileService.AddFiletoResource(Variables);
            string uri = Url.Link("DefaultGet",new { id = result.ID });
            return Request.CreateResponse(HttpStatusCode.OK);

抛出错误的部分是在

await Request.Content.ReadAsMultipartAsync(provider);

确切的错误是

Error writing MIME multipart body part to output stream.

内部例外

Exception of type 'System.OutOfMemoryException' was thrown.

我已经尝试创建一个自定义的BufferPolicySelector,如本帖子how to upload a large file with ASP.NET MVC4 Web Api with progressbar的第二个答案和许多其他地方所示,但这似乎没有什么帮助.

我也添加到我的web.config中：

<httpRuntime targetFramework="4.5" maxRequestLength="307200"/>

和

<security>
  <requestfiltering>
    <requestLimits maxAllowedContentLength="367001600"/>
  </requestfiltering>
</security>

解决方法

一个解决方案是使用MultipartFormDataStreamProvider而不是MultipartMemoryStreamProvider来避免在调用期间内存不足的异常

Request.Content.ReadAsMultipartAsync(..)

在为大型文件(> 100 MB)读取MultiPart文件内容时,我尝试使用MemoryStreamProvider时遇到类似的问题.为我工作的工作是使用MultipartFormDataStreamProvider.在ReadAsMultipartAsync调用期间,该文件将写入磁盘,如果在内存中需要它,可以稍后加载该文件.

这是一个例子：

Sending HTML Form Data in Web API: File Upload and Multipart MIME

string root = HttpContext.Current.Server.MapPath("~/App_Data");
    var provider = new MultipartFormDataStreamProvider(root);

    try
    {
        // Read the form data.
        await Request.Content.ReadAsMultipartAsync(provider);

        // This illustrates how to get the file names.
        foreach (multipartfileData file in provider.FileData)
        {
            Trace.WriteLine(file.Headers.Contentdisposition.FileName);
            Trace.WriteLine("Server file path: " + file.LocalFileName);
        }
        return Request.CreateResponse(HttpStatusCode.OK);
    }
    catch(...)