无法将文件从 Angular 8 上传到 Asp.net Core 2.2

Question

我有 asp.net 核心服务器（使用 .net 核心 2.2）有 FileUploadController 监听传入文件的 post 请求。

[HttpPost("Upload")]
// public async Task<IActionResult> Upload([FromForm(Name="file")]IFormFile file) {
// public async Task<IActionResult> Upload([FromForm]IFormFile file) {
public async Task<IActionResult> Upload(IFormFile file) {
   Console.WriteLine("***" + file);
   if(file == null) return BadRequest("NULL FILE");
   if(file.Length == 0) return BadRequest("Empty File");
       Console.WriteLine("***" + host.WebRootPath);
   if (string.IsNullOrWhiteSpace(host.WebRootPath))
   {
      host.WebRootPath = Path.Combine(Directory.GetCurrentDirectory(), "wwwroot");
   }
   var uploadsFolderPath = Path.Combine(host.WebRootPath, "uploads");
   if (!Directory.Exists(uploadsFolderPath)) Directory.CreateDirectory(uploadsFolderPath);
       var fileName = "Master" + Path.GetExtension(file.FileName);
       var filePath = Path.Combine(uploadsFolderPath, fileName);
       using (var stream = new FileStream(filePath, FileMode.Create))
       {
          await file.CopyToAsync(stream);
       }
       return Ok("Okay");
}

我已经创建了 angular 应用程序（使用 angular 版本 8），它可以选择要上传到 ClientApplication and I have created three post service that called to the api "http://localhost:5000/api/fileupload/upload 的文件。

标准 Angular HttpClient Post。当服务器读取时，IFormFile 为空。

const formData: FormData = new FormData();
formData.append('file', file, file.name);
// return this.http.post(this.endpoint, file);
return this.http.post(this.endpoint, formData); // Problem solved

添加了 HttpHeaders，我尝试清空 headers、undefined 以及来自 Whosebug 和 google.

的其他建议解决方案

const header = new HttpHeaders() //1
header.append('enctype', 'multipart/form-data'); //2
header.append('Content-Type', 'multipart/form-data'); //3

如果我将 httpheader 与资源放在请求中，服务器会给出 415（不支持的媒体类型）

我尝试来自“@angular/common/http”的 HttpRequest，它最终给我想要的结果。

const formData: FormData = new FormData();
formData.append('file', file, file.name);
const req = new HttpRequest('POST', this.endpoint, formData);
return this.http.request(req);

我想知道是bug还是我的误会？如果你查看在线教程，大多数开发人员使用 "this.HttpClient.post"。根据我的阅读，我可以使用 httpclient.post 和 angular 框架将为用户自动设置正确的 header。它似乎没有完成这项工作。

After thorough investigation, first error is my mistake of using file instead of formData, second error is header "content-type" declare in httpinterceptor which after removed, it load the file as expected.

@Injectable()
export class JwtInterceptor implements HttpInterceptor {
    intercept(request: HttpRequest<any>, next: HttpHandler): Observable<HttpEvent<any>> {
        // add authorization header with jwt token if available
        // if (request.url.indexOf('/upload')) {
        //     return next.handle(request);
        // }
        const token = localStorage.getItem('token');
        const currentUser = JSON.parse(localStorage.getItem('user'));
        if (currentUser && token) {
            request = request.clone({
                setHeaders: {
                    Authorization: `Bearer ${token}`,
                //    'Content-Type': 'application/json' <---- Main Problem.
                }
            });
        }
        return next.handle(request).pipe(catchError(err => this.handleError(err)));
    }
}

服务器：“https://github.com/phonemyatt/TestPlaygroundServer”

客户：“https://github.com/phonemyatt/TestPlayground”

Answer 1

下面的代码适合你

  uploadSecond(file: File) {
    const formData: FormData = new FormData();
    formData.append('file', file, file.name);
    return this.http.post('https://localhost:44393/api/fileupload/UploadSecond', formData);
  }

然后在你的控制器中

[HttpPost("UploadSecond")]
[DisableRequestSizeLimit]
public async Task<IActionResult> UploadSecond([FromForm]IFormFile file)

Answer 2

在第一个不起作用的示例中，您将 file 传递给 post(...) 而不是 formData。应该是：

const formData: FormData = new FormData();
formData.append('file', file, file.name);
return this.http.post(this.endpoint, formData);

您为控制器显示的代码似乎是正确的，因此这应该是唯一需要的更改。您 不需要 对从 Angular.

发送的请求设置任何自定义 headers

Answer 3

如果您在客户端中使用 FormData，您可以获得这样的文件。

[HttpPost("Upload"), DisableRequestSizeLimit]
        public ActionResult Upload()
        {
            try
            {
                var file = Request.Form.Files[0];
                var folderName = Path.Combine("Resources","Images");
                var pathToSave = Path.Combine(Directory.GetCurrentDirectory(), folderName);

                if (file.Length > 0)
                {
                    var fileName = ContentDispositionHeaderValue.Parse(file.ContentDisposition).FileName.Trim('"');
                    var fullPath = Path.Combine(pathToSave, fileName);
                    var dbPath = Path.Combine(folderName, fileName);

                    using (var stream = new FileStream(fullPath, FileMode.Create))
                    {
                        file.CopyTo(stream);
                    }

                    return Ok(new { dbPath });
                }
                else
                {
                    return BadRequest();
                }
            }
            catch (Exception ex)
            {
                return StatusCode(500, "Internal server error");
            }
        }

无法将文件从 Angular 8 上传到 Asp.net Core 2.2

Unable to File Upload From Angular 8 to Asp.net Core 2.2

c#

angular

typescript

asp.net-core

angular8