Web API 2中的文件上传问题，然后是html表单帖子

Question

Web API 2中的文件上载问题

虽然我上传文件并附上表单发布此工作文件，但我发送来自Rest Client的相同信息，例如Google Chrome中的Postman或使用Android或iOS应用程序发布文件信息Web Api 2代码未检测到文件multipart / form-post

以下是我的HTML代码

    <form enctype="multipart/form-data" method="post" action="/api/feedback">
    <input type="text" name="Scope" placeholder="Scope" value="feedback">
    <input type="text" name="Lang" placeholder="Lang" value="en">
    <input type="text" name="Collection" placeholder="Collection" value="7b22437573746f6d65724964223a392c2253657276696365526571756573744964223a312c224174746974756465223a332e322c22576f726b457468696373223a342e322c2248796769656e65223a352c22416d6f757450616964223a333132332e327d">
    <input type="file" name="Photo1" placeholder="Photo1">
    <input type="file" name="Photo2" placeholder="Photo2">
    <input type="file" name="Signature" placeholder="Signature">
    <input type="submit" value="Submit">
</form>

此.Net Web Api 2代码

        public async Task<Result> Post()
    {
        var model = new ApiData();
        var result = new Result();
        if (Request.Content.IsMimeMultipartContent())
        {
            try
            {
                string root = HttpContext.Current.Server.MapPath("~/assets/temp");
                var provider = new MultipartFormDataStreamProvider(root);

                var sb = new System.Text.StringBuilder(); // Holds the response body
                // Read the form data and return an async task.
                await Request.Content.ReadAsMultipartAsync(provider);
                // This illustrates how to get the form data.
                foreach (var key in provider.FormData.AllKeys)
                {
                    foreach (var val in provider.FormData.GetValues(key))
                    {
                        if (key.Equals("Scope"))
                            model.Scope = val;
                        if (key.Equals("Lang"))
                            model.Lang = val;
                        if (key.Equals("Collection"))
                            model.Collection = val;
                    }

                }
                if (!model.Scope.Equals("feedback", StringComparison.InvariantCultureIgnoreCase))
                    result.Text = "Missing Scope.";
                else
                {
                    var Util = new Utils();
                    model.Collection = Util.ToString(model.Collection);
                    var _Feedback = JsonConvert.DeserializeObject<Feedback>(model.Collection);
                    try
                    {
                        // This illustrates how to get the file names for uploaded files.
                        foreach (var file in provider.FileData)
                        {
                            FileInfo fileInfo = new FileInfo(file.LocalFileName);
                            string BaseUrl = HttpContext.Current.Server.MapPath("~/assets/feedback/");
                            string oldFile = file.Headers.ContentDisposition.FileName.TrimStart('"').TrimEnd('"');
                            string NewName = string.Format("{0}{1}", Util.NewGuid, Path.GetExtension(oldFile));
                            if (file.Headers.ContentDisposition.Name.ToLower().Contains("photo"))
                            {
                                _Feedback.Photos = string.IsNullOrEmpty(_Feedback.Photos) ? NewName : _Feedback.Photos + "," + NewName;
                                fileInfo.MoveTo(BaseUrl + NewName);
                            }
                            else if (string.IsNullOrEmpty(_Feedback.Signatures) && file.Headers.ContentDisposition.Name.ToLower().Contains("signature"))
                            {
                                _Feedback.Signatures = NewName;
                                fileInfo.MoveTo(BaseUrl + NewName);
                            }
                        }
                    }
                    catch { }

                    if (Util.IsRequired(_Feedback.CustomerId)
                            && Util.IsRequired(_Feedback.ServiceRequestId)
                            && Util.IsRequired(_Feedback.Attitude)
                            && Util.IsRequired(_Feedback.WorkEthics)
                            && Util.IsRequired(_Feedback.Hygiene)
                            )
                    {
                        var feedback = new Feedback()
                        {
                            CustomerId = _Feedback.CustomerId,
                            ServiceRequestId = _Feedback.ServiceRequestId,
                            Attitude = _Feedback.Attitude,
                            WorkEthics = _Feedback.WorkEthics,
                            Hygiene = _Feedback.Hygiene,
                            AmoutPaid = _Feedback.AmoutPaid,
                            Photos = _Feedback.Photos,
                            Signatures = _Feedback.Signatures,
                            Created = DateTime.UtcNow,
                            Updated = DateTime.UtcNow
                        };

                        db.Feedbacks.Add(feedback);
                        db.SaveChanges();
                        if (feedback.Id != default(int))
                        {
                            result.Success = true;
                            result.Text = "Success";
                        }
                    }
                    else
                    {
                        result.Text = "Required Parameters missing.";
                    }
                }
            }
            catch
            {
                result.Text = "Error";
            }
        }
        else
            result.Text = "Signature or photo missing";
        return result;
    }

这是Postmen请求

  

在Fiddler客户端中公开发布请求我已经看到在使用html表单发布时，在multipart / form-data中存在边界;虽然Postman或其他RestClient中没有边界。

Answer 1

这可能是邮递员bug。

总而言之，如果使用Postman设置Content-Type标头，它似乎会覆盖默认浏览器功能而不添加边界。大多数时候这是一件好事，但不适用于multipart / form-data，因为我们需要浏览器为我们添加边界。尝试删除Content-Type标头。发送实际的帖子时，浏览器会自动添加正确的标题并创建边界。

您的WebApi代码看起来很好。你的if检查只是假的。

//This will be false since it's a malformed request.
if (Request.Content.IsMimeMultipartContent())

Answer 2

我知道这是一篇老文章，但是我认为这可以帮助遇到相同问题的人。在邮递员中删除Content-Type标头。该请求将通过。