private async Task GenerateToken(HttpContext context)
{
    var username = context.Request.Form["username"];
    var password = context.Request.Form["password"];
    //Remainder of login code
}

login(username: string, password: string): Observable<boolean> {
    let headers = new Headers({ 'Content-Type': 'application/json' });
    let options = new RequestOptions({ headers: headers });
    let body = JSON.stringify({ username: username, password: password });
        return this.http.post(this._api.apiUrl + 'token', body, options)
            .map((response: Response) => {

            });
    }