Adding Authentication token to file upload in angular 2 - angularjs

Question

How can i add authentication token to the file upload service? When i login in my application, i am able to retrieve the token from the backend but i am having a hard time as to how to add it the to file service. When i try to upload a file, it get an error saying "token_not_provided". As it is in my service, i have added the authentication token in my header so whenever i make a request, the server is aware of the user at hand. But with the file submission, i have no idea of how to append the authentication token to the file service
#Component({
providers:[AuthenticationService]
})
#Injectable()
export class FileUploadService {
public progress$;
public progressObserver;
public progress : number;
public token: string;
public headers:string;
constructor (private auth:AuthenticationService) {
this.progress$ = Observable.create(observer => {
this.progressObserver = observer
}).share();
}
makeFileRequest (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(this.headers, this.auth.token);//modified
xhr.send(formData);
});
}
}
//service
updateFood(food:any) {
const body = JSON.stringify(food);
const headers = new Headers({ 'Authorization': 'Bearer ' + this.authenticationService.token });
return this.http.put('http://localhost:9000/, body, {headers: headers})
.map((data:Response) => data.json());
}

Answer 1

Somewhere between your xhr.open and xhr.close you can append headers
xhr.setRequestHeader(header, value);
See https://developer.mozilla.org/en-US/docs/Web/API/XMLHttpRequest/setRequestHeader for more detailed documentation