用Spring云网关处理全局异常

Question

我正在使用Spring Cloud Gateway Greenwich.sr1和Spring Boot 2.1.5。我正试图为我的下游服务创建一个网关。网关的部分工作是为下游请求提供全局错误页。当下游服务返回HTTP 403响应时，我希望网关提供一个合适的错误页面。

public class ForbiddenFilterFactory extends AbstractGatewayFilterFactory<Object> {

    @Override
    public String name() {
        return "Forbidden";
    }

    @Override
    public GatewayFilter apply(Object o) {
        return (exchange, chain) -> chain.filter(exchange).then(
                Mono.defer(() -> {
                    if (!exchange.getResponse().isCommitted() &&
                            HttpStatus.FORBIDDEN.equals(exchange.getResponse().getStatusCode())) {
                        return Mono.error(new ResponseStatusException(HttpStatus.FORBIDDEN));
                    }
                    return Mono.empty();
                }));
    }
}

有没有不同的方法让它起作用？

Answer 1

我通过使用自定义的ServerHttpResponseDecorator解决了这个问题。代码的关键部分是覆盖WriteWith方法以提供自定义正文：

ServerHttpResponseDecorator responseDecorator = new ServerHttpResponseDecorator(exchange.getResponse()) {
    @Override
    public Mono<Void> writeWith(Publisher<? extends DataBuffer> body) {
        if (shouldServeErrorPage(exchange)) {
            exchange.getResponse().getHeaders().setContentLength(-1);
            return errorWebExceptionHandler.handle(exchange, new ResponseStatusException(getHttpStatus(exchange)));
        } else {
            return getDelegate().writeWith(body);
        }
    }

    @Override
    public Mono<Void> writeAndFlushWith(
            Publisher<? extends Publisher<? extends DataBuffer>> body) {
        if (shouldServeErrorPage(exchange)) {
            return writeWith(Flux.from(body).flatMapSequential(p -> p));
        } else {
            return getDelegate().writeAndFlushWith(body);
        }
    }

    private boolean shouldServeErrorPage(ServerWebExchange exchange) {
        HttpStatus statusCode = getHttpStatus(exchange);
        return statusCode.is5xxServerError() || statusCode.is4xxClientError();
    }
};

return chain.filter(exchange.mutate().response(responseDecorator).build());

我在https://github.com/tine2k/scg-global-error-page上推送了一个工作示例