使用ASP.Net Web API进行多部分表单POST

我遇到了故障的任务问题,在第一个请求被触发并完成后触发了所有请求.

这是场景：我有一个示例页面,它将文件和其他参数一起发布到Web API Post方法.它第一次正常工作,文件上传.但是,所有后续请求都会在故障状态下结束任务.我得到“MIME多部分流的意外结束. MIME多部分消息不完整.“任何想法为什么？

下面粘贴的是我的Post方法的源代码,示例html表单和Aggregate Exception.

public Task<HttpResponseMessage> Post([FromUri]string memberNumber)
    {
        // Check if the request contains multipart/form-data.
        if (!Request.Content.IsMimeMultipartContent())
        {
            throw new HttpResponseException(HttpStatusCode.UnsupportedMediaType);
        }

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

        // Read the form data and return an async task.
        var task = Request.Content.ReadAsMultipartAsync(provider).
            ContinueWith(t =>
            {
                if (t.IsFaulted || t.IsCanceled)
                {
                    throw new HttpResponseException(Request.CreateErrorResponse(HttpStatusCode.InternalServerError,t.Exception));
                }

                return Request.CreateResponse(HttpStatusCode.OK,new MyModel());
            });

        return task;
    }

我正在使用这样的示例表单解雇此web api：

<form name="form1" method="post" enctype="multipart/form-data" action="api/claims/asd123" style="margin:auto;width:500px;">
    <div>
        <label for="HCPracticeNumber">HC Pratice Number:</label>
        <input type="text" name="HCPracticeNumber" id="HCPracticeNumber"/>
    </div>
    <div>
        <label for="ServiceDate">Service/Treatment date:</label>
        <input type="text" name="ServiceDate" id="ServiceDate"/>
    </div>
    <div>
        <label for="AmountClaimed">Amount Claimed:</label>
        <input type="text" name="AmountClaimed" id="AmountClaimed"/>
    </div>
    <div>
        <label for="Image">Image Attachment:</label>
        <input name="Image" type="file" />
    </div>
    <div>
        <input type="submit" value="Submit" />
    </div>
</form>

返回的AggregateException如下：

<Error>
<Message>An error has occurred.</Message>
    <ExceptionMessage>One or more errors occurred.</ExceptionMessage>
    <ExceptionType>System.AggregateException</ExceptionType>
    <StackTrace/>
    <InnerException>
        <Message>An error has occurred.</Message>
        <ExceptionMessage>
            Unexpected end of MIME multipart stream. MIME multipart message is not complete.
        </ExceptionMessage>
        <ExceptionType>System.IO.IOException</ExceptionType>
        <StackTrace>
            at System.Net.Http.Formatting.Parsers.MimeMultipartBodyPartParser.<ParseBuffer>d__0.MoveNext() at System.Net.Http.HttpContentMultipartExtensions.MoveNextPart(MultipartAsyncContext context)
        </StackTrace>
    </InnerException>
</Error>

更新：

在Filip在他的博客网站上提出建议后,我修改了post方法,将流位置重置为0,如下所示：

Stream reqStream = Request.Content.ReadAsStreamAsync().Result;
        if (reqStream.CanSeek)
        {
            reqStream.Position = 0;
        }
        var task = Request.Content.ReadAsMultipartAsync(provider).
            ContinueWith(t =>
            {
                if (t.IsFaulted || t.IsCanceled)
                {
                    throw new HttpResponseException(
                    Request.CreateErrorResponse(HttpStatusCode.InternalServerError,new MyModel());

            });

但是,这是非常有气质的代码.它的工作有时它不会在其他时间.换句话说,它并没有完全解决问题.