使用 guid 和文件扩展名的 ASP.NET WebApi 文件上传

Question

我目前能够保存上传到 WebAPI 控制器的文件，但我希望能够将文件保存为具有正确文件扩展名的 guid，以便可以正确查看。

代码：

 [ValidationFilter]
    public HttpResponseMessage UploadFile([FromUri]string AdditionalInformation)
    {
        var task = this.Request.Content.ReadAsStreamAsync();
        task.Wait();

        using (var requestStream = task.Result)
        {
            try
            {
                // how can I get the file extension of the content and append this to the file path below?

                using (var fileStream = File.Create(HttpContext.Current.Server.MapPath("~/" + Guid.NewGuid().ToString())))
                {
                    requestStream.CopyTo(fileStream);
                }
            }
            catch (IOException)
            {                    
                throw new HttpResponseException(HttpStatusCode.InternalServerError);
            }
        }

        HttpResponseMessage response = new HttpResponseMessage();
        response.StatusCode = HttpStatusCode.Created;
        return response;
    }

我似乎无法处理内容的实际文件名。我认为 headers.ContentDisposition.FileName 可能是候选人，但似乎没有人满。

Answer 1

感谢上面的 cmets 为我指明了正确的方向。

为了阐明最终解决方案，我使用了 MultipartFormDataStreamProvider 自动流式传输文件。该代码在我在这里发布到另一个问题的另一个问题中： MultipartFormDataStreamProvider and preserving current HttpContext

下面列出了我的完整提供商代码。生成 guid 文件名的关键是覆盖 GetLocalFileName 函数并使用 headers.ContentDisposition 属性。提供程序处理将内容流式传输到文件。

public class MyFormDataStreamProvider : MultipartFormDataStreamProvider
{
    public MyFormDataStreamProvider (string path)
        : base(path)
    { }

    public override Stream GetStream(HttpContent parent, HttpContentHeaders headers)
    {
        // restrict what images can be selected
        var extensions = new[] { "png", "gif", "jpg" };
        var filename = headers.ContentDisposition.FileName.Replace("\"", string.Empty);

        if (filename.IndexOf('.') < 0)
            return Stream.Null;

        var extension = filename.Split('.').Last();

        return extensions.Any(i => i.Equals(extension, StringComparison.InvariantCultureIgnoreCase))
                   ? base.GetStream(parent, headers)
                   : Stream.Null;

    }

    public override string GetLocalFileName(System.Net.Http.Headers.HttpContentHeaders headers)
    {
        // override the filename which is stored by the provider (by default is bodypart_x)
        string oldfileName = headers.ContentDisposition.FileName.Replace("\"", string.Empty);
        string newFileName = Guid.NewGuid().ToString() + Path.GetExtension(oldfileName);

        return newFileName;       
    }
}