Spring Cloud 网关路由—Spring Cloud Gateway 自定义过滤器
在一篇我们详细介绍了Spring Cloud Gateway路由的配置与使用,并且介绍了部分过滤器的配置,不过我们配置的都是Spring Cloud Gateway内部定义的过滤器和断言,本篇博客讲解如何创建自定义断言与过滤器的使用。
自定义断言工厂需要实现RoutePredicateFactory,不过Spring Cloud Gateway为我们提供了一个抽象类,我们只需要继承该抽象类AbstractRoutePredicateFactory 即可。如下为自定义断言工厂的一个示例。
public class MyRoutePredicateFactory extends AbstractRoutePredicateFactory<HeaderRoutePredicateFactory.Config> { public MyRoutePredicateFactory() { super(Config.class); } @Override public Predicate<ServerWebExchange> apply(Config config) { // grab configuration from Config object return exchange -> { //获取请求 ServerHttpRequest request = exchange.getRequest(); //判断请求是否与配置匹配 return matches(config, request); }; } public static class Config { //为断言配置属性 } }
与断言工厂类似,GatewayFilter的自定义需要实现GatewayFilterFactory接口,它也给我们提供了一个抽象类,我们只需继承该类AbstractGatewayFilterFactory即可,如下为自定义GatewayFilter的一个示例。
public class PreGatewayFilterFactory extends AbstractGatewayFilterFactory<PreGatewayFilterFactory.Config> { public PreGatewayFilterFactory() { super(Config.class); } @Override public GatewayFilter apply(Config config) { // grab configuration from Config object return (exchange, chain) -> { //If you want to build a "pre" filter you need to manipulate the //request before calling chain.filter ServerHttpRequest.Builder builder = exchange.getRequest().mutate(); //use builder to manipulate the request return chain.filter(exchange.mutate().request(request).build()); }; } public static class Config { //Put the configuration properties for your filter here } } public class PostGatewayFilterFactory extends AbstractGatewayFilterFactory<PostGatewayFilterFactory.Config> { public PostGatewayFilterFactory() { super(Config.class); } @Override public GatewayFilter apply(Config config) { // grab configuration from Config object return (exchange, chain) -> { return chain.filter(exchange).then(Mono.fromRunnable(() -> { ServerHttpResponse response = exchange.getResponse(); //Manipulate the response in some way })); }; } public static class Config { //Put the configuration properties for your filter here } }
上面的两个示例为官方文档提供的两个示例,其中第一个为更改request请求的内容,第二个示例为更改response响应的内容,我们在编写自定义过滤器之前,最好可以先阅读源码中的一些过滤器作为示范。自定义GlobalFilter全局过滤器时需要实现GlobalFilter接口,如下示例为官方文档提供的两种自定义GlobalFilter示例:
@Bean public GlobalFilter customGlobalFilter() { return (exchange, chain) -> exchange.getPrincipal() .map(Principal::getName) .defaultIfEmpty("Default User") .map(userName -> { //添加请求头 exchange.getRequest().mutate().header("CUSTOM-REQUEST-HEADER", userName).build(); return exchange; }) .flatMap(chain::filter); } @Bean public GlobalFilter customGlobalPostFilter() { return (exchange, chain) -> chain.filter(exchange) .then(Mono.just(exchange)) .map(serverWebExchange -> { //adds 响应头 serverWebExchange.getResponse().getHeaders().set("CUSTOM-RESPONSE-HEADER", HttpStatus.OK.equals(serverWebExchange.getResponse().getStatusCode()) ? "It worked": "It did not work"); return serverWebExchange; }) .then(); }
Spring Cloud Gateway的使用就介绍三篇,其源码这里不再讲解,有兴趣的可以自行阅读Spring Cloud Gateway源码,后续有时间也会更新一些源码的内容,下面的部分将介绍分布式消息Spring Cloud Stream的使用。
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