Uploading Files in angular 2 - csv

Question

I am trying to upload a csv/xlxs file in angular 2 but whenever i submit the file, i get an exception file could not upload. please try again from my backend although it works fine on postman. What could be wrong in my code?
//service
constructor (private authenticate:AuthenticationService) {
this.filetrack = Observable.create(observer => {
this.progressObserver = observer
}).share();
}
SendRequest (url: string, params: string[], files: File[]) {
return Observable.create(observer => {
let formData: FormData = new FormData(),
xhr: XMLHttpRequest = new XMLHttpRequest();
for (let i = 0; i < files.length; i++) {
formData.append("uploads[]", files[i], files[i].name);
}
xhr.onreadystatechange = () => {
if (xhr.readyState === 4) {
if (xhr.status === 200) {
observer.next(JSON.parse(xhr.response));
observer.complete();
} else {
observer.error(xhr.response);
}
}
};
xhr.upload.onprogress = (event) => {
this.progress = Math.round(event.loaded / event.total * 100);
this.progressObserver.next(this.progress);
};
xhr.open('POST', url, true);
xhr.setRequestHeader('Authorization', 'Bearer ' + this.authenticate.user_token);
xhr.send(formData);
});
}
}
//component
export class FileUploadComponent {
constructor(private service:FileUploadService) {
this.service.filetrack.subscribe(
data => {
console.log('progress = '+data);
});
}
onChange(event) {
console.log('onChange');
let files = event.target.files;
console.log(files);
this.service.SendRequest('http://localhost:8000/register/v1/file/country', [], files).subscribe(() => {
console.log('sent');
});
}
}

Answer 1

You have to set another header to be able to upload a file:
xhr.setRequestHeader("Content-Type", "multipart/form-data");