如何使用Angular2向外部API发送POST请求？

Question

我正在尝试利用CORS发布帖子请求。我偶然发现了几篇与CORS相关的文章/答案，但不知何故无法正常工作。

据我所知，access-control-allow-origin: *将被设置在服务器端来得到这个工作，但我在这里是一个角 - cli项目。

我的项目纯粹是基于Angular 2.1的，并且没有涉及后端服务器。有关如何正确设置它的任何建议将受到高度赞赏。

是我得到确切的错误是这样的：

"NetworkError: 404 Not Found - https://flowxo.com/hooks/a/rbpja7r2/?usertype=User" 

和此警告在控制台：

Cross-Origin Request Blocked: The Same Origin Policy disallows reading the 
remote resource at https://flowxo.com/hooks/a/rbpja7r2/?usertype=User. 
(Reason: CORS header 'Access-Control-Allow-Origin' missing). 

更新：

这里是我如何努力使POST请求：

let headers = new Headers(); 
headers.append('Access-Control-Allow-Headers', 'Content-Type'); 
headers.append('Content-Type', 'application/json'); 
headers.append('Access-Control-Allow-Methods', 'POST, OPTIONS'); 
headers.append('Access-Control-Allow-Origin', '*'); 
return this.http.post(
    this.flowxoUrl, 
    JSON.stringify(formData), 
    {headers: headers} 
) 
    .map((res:Response) => res.json()) 
    .catch((error:any) => Observable.throw(error.json().error || 'Server error')); //...errors if any 

Answer 1

这是服务器端问题，而不是Angular。

您的服务器应回应Access-Control-Allow-Origin表头。

的Java（春季）例如：

@Component 
@Order(Ordered.HIGHEST_PRECEDENCE) 
public class SimpleCorsFilter implements Filter { 
    @Override 
    public void init(FilterConfig filterConfig) throws ServletException {} 

    @Override 
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException { 
     HttpServletResponse response = (HttpServletResponse) servletResponse; 
     HttpServletRequest request = (HttpServletRequest) servletRequest; 
     response.setHeader("Access-Control-Allow-Origin", "*"); //you can specify domains here * - is a wildcard, it will allow all origins to request 
     response.setHeader("Access-Control-Allow-Methods", "POST, GET, OPTIONS, DELETE, PUT"); 
     response.setHeader("Access-Control-Max-Age", "3600"); 
     response.setHeader("Access-Control-Allow-Headers", "x-requested-with, authorization, content-type"); 

     if("OPTIONS".equalsIgnoreCase(request.getMethod())) { 
      response.setStatus(HttpServletResponse.SC_OK); 
     } else { 
      filterChain.doFilter(servletRequest, servletResponse); 
     } 
    } 

    @Override 
    public void destroy() {} 
}