I have a rest web service and now I want to make a post request from ionic 2 frontend app to authentication rest method.
On my login component I have:
...this._restClient.post(
                'authentication',
                body,
                (data) => this.handleSuccessAuthenticate(data),
                (data) => this.handleErrorAuthenticate(data)
            );...
On my provider my _restClient code is:
public post(resource: string, data: Object, onSuccess: restClient, onError: callbackRestClient) {
        var httpResult: Observable<Response>;
        if (data === null) {
            httpResult = this._http.post(this.getUrl(resource), '{}', { headers: this.getHeaders() });
        } else {
            httpResult = this._http.post(this.getUrl(resource), JSON.stringify(data), { headers: this.getHeaders() });
        }
        this.handleResult(httpResult, onSuccess, onError);
    }
I also have a private method to set headers:
   private getHeaders() {
        var headers = new Headers();
        headers.append('Accept', 'application/json');
        headers.append('Content-Type', 'application/json');
        headers.append('Access-Control-Allow-Origin', '*');
        headers.append('Access-Control-Allow-Credentials', 'true');
        headers.append("Access-Control-Allow-Methods", "POST, GET, OPTIONS, PUT, DELETE");
        headers.append("Access-Control-Allow-Headers", "Content-Type, Content-Length, Accept-Encoding, X-CSRF-Token");
        return headers;
    }
I have the classic message:
Response to preflight request doesn't pass access control check: No 'Access-Control-Allow-Origin' header is present on the requested resource
What I´m doing wrong?
 
    