How do you POST a FormData object in Angular 2?

Question

I need to upload a file and send some json along with it, I have this function:

POST_formData(url, data) {
        var headers = new Headers(), authtoken = localStorage.getItem('authtoken');

        if (authtoken) {
            headers.append("Authorization", 'Token ' + authtoken)
        }

        headers.append("Accept", 'application/json');
        headers.delete("Content-Type");

        var requestoptions = new RequestOptions({
            method: RequestMethod.Post,
            url: this.apiURL + url,
            headers: headers,
            body: data
        })

        return this.http.request(new Request(requestoptions))

        .map((res: Response) => {
            if (res) {
                return { status: res.status, json: res.json() }
            }
        })
    }

My issue is, if I set the content-type to "multipart/form-data" my server complains about the boundaries, if I remove the content-type header completely, my server complains that it "text/plain" a supported media type.

So, how do you send FormData with angular2?

Answer 1

Template:

<label class="btn btn-primary">
  <input type="file" style="display: none;" multiple="true" (change)="fileChange($event)" accept=".xml">
  <span>Click Me!</span>
</label>

UPD: Angular 5 - HttpClient + Typescript

onFileUpload(event: EventTarget) {

  const eventObj: MSInputMethodContext = <MSInputMethodContext>event;
  const target: HTMLInputElement = <HTMLInputElement>eventObj.target;
  const files: FileList = target.files;

  const formData: FormData = new FormData();

  for (let i = 0; i < files.length; i++) {
    formData.append('file', files[i]);
  }

  // POST
  this.httpClient.post<AnalyzedData>(uploadUrl, formData).subscribe(...);
}

old Http lib - before Angular 4.3:

fileChange(event) {
    let files = event.target.files;
        if (files.length > 0) {
        let formData: FormData = new FormData();
        for (let file of files) {
             formData.append('files', file, file.name);
        }
        let headers = new Headers();
        headers.set('Accept', 'application/json');
        let options = new RequestOptions({ headers: headers });
        this.http.post(uploadURL, formData, options)
            .map(res => res.json())
            .catch(error => Observable.throw(error))
            .subscribe(
            data => {
                // Consume Files
                // ..
                console.log('uploaded and processed files');
            },
            error => console.log(error),
            () => {
                this.sleep(1000).then(() =>
                    // .. Post Upload Delayed Action
                )
            });
    }
}