java - 如何将 CORS header 设置为内部服务器错误响应？

Question

我有一个带有 REST 接口(interface)的 Java 应用服务器，由 resteasy 提供，我有下面的 CORS 过滤器

@Provider
public class CORSFilter implements ContainerResponseFilter {

    public void filter(ContainerRequestContext cReq, ContainerResponseContext cResp) {
        cResp.getHeaders().add("Access-Control-Allow-Origin", "*");
        cResp.getHeaders().add("Access-Control-Allow-Headers", "origin, content-type, accept, authorization, auth-token");
        cResp.getHeaders().add("Access-Control-Allow-Credentials", "true");
        cResp.getHeaders().add("Access-Control-Allow-Methods", "GET, POST, PUT, DELETE, OPTIONS, HEAD");
        cResp.getHeaders().add("Access-Control-Max-Age", "1209600");
    }

}

所有请求都返回 CORS header :

OPTIONS 200 OK
Access-Control-Allow-Credentials:"true"
Access-Control-Allow-Headers:"origin, content-type, accept, authorization, auth-token"
Access-Control-Allow-Methods:"GET, POST, PUT, DELETE, OPTIONS, HEAD"
Access-Control-Allow-Origin:"*"
Access-Control-Max-Age:"1209600"
Allow:"HEAD, GET, OPTIONS"
Connection:"keep-alive"
Content-Length:"18"
Content-Type:"text/plain"
Date:"Thu, 15 Jan 2015 15:23:01 GMT"
Server:"WildFly/8"

除非我有一个返回错误代码 500 的内部异常:

GET 500 Internal Server Error
Connection:"keep-alive"
Content-Length:"8228"
Content-Type:"text/html; charset=UTF-8"
Date:"Thu, 15 Jan 2015 15:23:01 GMT"

如何让 500 个响应包含这些 header ？

Answer 1

使用 ExceptionMapper :

@Provider
public class CorsExceptionMapper implements ExceptionMapper<Exception> {

    @Override
    public Response toResponse(Exception ex) {
        ResponseBuilder responseBuilder = Response.serverError();
        responseBuilder.header("Access-Control-Allow-Origin", "*");
        responseBuilder.header("Access-Control-Allow-Headers", "origin, content-type, accept, authorization, auth-token");
        responseBuilder.header("Access-Control-Allow-Credentials", "true");
        responseBuilder.header("Access-Control-Allow-Methods", "GET, POST, PUT, DELETE, OPTIONS, HEAD");
        responseBuilder.header("Access-Control-Max-Age", "1209600");
        return responseBuilder.build();
    }

}

为避免标题重复，您应该使用:

cResp.getHeaders().putSingle() 

在 ContainerResponseFilter 中。