如何为多部分/表单数据设置Web API控制器 [英] How to set up a Web API controller for multipart/form-data

问题描述

我正在尝试解决这个问题.我的代码没有得到任何有用的错误消息，所以我使用了其他东西来生成东西.错误消息后，我已附加了该代码.我找到了教程关于它，但是我不知道如何用我现有的东西来实现它.这是我目前拥有的:

I am trying to figure this out. I was not getting any useful error messages with my code so I used something else to generate something. I have attached that code after the error message. I have found a tutorial on it but I do not know how to implement it with what I have. This is what I currently have:

public async Task<object> PostFile()
    {
        if (!Request.Content.IsMimeMultipartContent())
            throw new Exception();


        var provider = new MultipartMemoryStreamProvider();
        var result = new { file = new List<object>() };
        var item = new File();

        item.CompanyName = HttpContext.Current.Request.Form["companyName"];
        item.FileDate = HttpContext.Current.Request.Form["fileDate"];
        item.FileLocation = HttpContext.Current.Request.Form["fileLocation"];
        item.FilePlant = HttpContext.Current.Request.Form["filePlant"];
        item.FileTerm = HttpContext.Current.Request.Form["fileTerm"];
        item.FileType = HttpContext.Current.Request.Form["fileType"];

        var manager = new UserManager<ApplicationUser>(new UserStore<ApplicationUser>(new ApplicationDbContext()));
        var user = manager.FindById(User.Identity.GetUserId());

        item.FileUploadedBy = user.Name;
        item.FileUploadDate = DateTime.Now;

        await Request.Content.ReadAsMultipartAsync(provider)
         .ContinueWith(async (a) =>
         {
             foreach (var file in provider.Contents)
             {
                 if (file.Headers.ContentLength > 1000)
                 {
                     var filename = file.Headers.ContentDisposition.FileName.Trim('\"');
                     var contentType = file.Headers.ContentType.ToString();
                     await file.ReadAsByteArrayAsync().ContinueWith(b => { item.FilePdf = b.Result; });
                 }


             }


         }).Unwrap();

        db.Files.Add(item);
        db.SaveChanges();
        return result;

    }

错误:

对象{消息:此资源不支持请求实体的媒体类型'multipart/form-data'."，异常消息:没有MediaTypeFormatter可用于读取媒体类型为'multipart/form的对象内容-data'."，exceptionType:"System.Net.Http.UnsupportedMediaTypeException"，stackTrace:在System.Net.Http.HttpContentExtensions.ReadAs…atterLogger，CancellationToken cancelledToken)"} exceptionMessage:没有MediaTypeFormatter可用于读取对象媒体类型为'multipart/form-data'的内容中的类型为'HttpPostedFileBase'." exceptionType:"System.Net.Http.UnsupportedMediaTypeException"消息:此请求实体的媒体类型为"multipart/form-data"，不支持资源."stackTrace:"，位于System.Net.Http.HttpContentExtensions.ReadAsAsync [T](HttpContent内容，类型，IEnumerable 1 formatters, IFormatterLogger formatterLogger, CancellationToken cancellationToken) ↵ at System.Net.Http.HttpContentExtensions.ReadAsAsync(HttpContent content, Type type, IEnumerable 1格式化程序，IFormatterLogger formatterLogger，CancellationToken cancelledToken)

Object {message: "The request entity's media type 'multipart/form-data' is not supported for this resource.", exceptionMessage: "No MediaTypeFormatter is available to read an obje…om content with media type 'multipart/form-data'.", exceptionType: "System.Net.Http.UnsupportedMediaTypeException", stackTrace: " at System.Net.Http.HttpContentExtensions.ReadAs…atterLogger, CancellationToken cancellationToken)"}exceptionMessage: "No MediaTypeFormatter is available to read an object of type 'HttpPostedFileBase' from content with media type 'multipart/form-data'."exceptionType: "System.Net.Http.UnsupportedMediaTypeException"message: "The request entity's media type 'multipart/form-data' is not supported for this resource."stackTrace: " at System.Net.Http.HttpContentExtensions.ReadAsAsync[T](HttpContent content, Type type, IEnumerable1 formatters, IFormatterLogger formatterLogger, CancellationToken cancellationToken) ↵ at System.Net.Http.HttpContentExtensions.ReadAsAsync(HttpContent content, Type type, IEnumerable1 formatters, IFormatterLogger formatterLogger, CancellationToken cancellationToken)

用于生成错误消息的代码:

Code used to generate error message:

    [HttpPost]
    public string UploadFile(HttpPostedFileBase file)
    {

        if (file.ContentLength > 0)
        {
            var fileName = Path.GetFileName(file.FileName);
            var path = Path.Combine(HttpContext.Current.Server.MapPath("~/uploads"), fileName);
            file.SaveAs(path);


        }
        return "/uploads/" + file.FileName;
    }

班级:

public class File
{
    public int FileId { get; set; }
    public string FileType { get; set; }
    public string FileDate { get; set; }
    public byte[] FilePdf { get; set; }
    public string FileLocation { get; set; }
    public string FilePlant { get; set; }
    public string FileTerm { get; set; }
    public DateTime? FileUploadDate { get; set; }
    public string FileUploadedBy { get; set; }

    public string CompanyName { get; set; }
    public virtual ApplicationUser User { get; set; }
}

推荐答案

我通常仅在 Mvc控制器中使用 HttpPostedFileBase 参数.处理 ApiControllers 时，请尝试检查 HttpContext.Current.Request.Files 属性是否包含传入文件:

I normally use the HttpPostedFileBase parameter only in Mvc Controllers. When dealing with ApiControllers try checking the HttpContext.Current.Request.Files property for incoming files instead:

[HttpPost]
public string UploadFile()
{
    var file = HttpContext.Current.Request.Files.Count > 0 ?
        HttpContext.Current.Request.Files[0] : null;

    if (file != null && file.ContentLength > 0)
    {
        var fileName = Path.GetFileName(file.FileName);

        var path = Path.Combine(
            HttpContext.Current.Server.MapPath("~/uploads"),
            fileName
        );

        file.SaveAs(path);
    }

    return file != null ? "/uploads/" + file.FileName : null;
}

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