How to set up a Web API controller for multipart/form-data

Question

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;      } 

Error:

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)

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;     } 

Class:

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; } } 

Answer 1

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; }