学习一下SpringCloudGateWay

management:
  endpoints:
    web:
      exposure:
        include: '*'

spring:
  cloud:
    gateway:
      routes:
        - id: after_route
          uri: https://example.org
          predicates:
            - After=2022-01-25T07:42:47.789-07:00[America/Denver]

public class BeforeRouteDemoPredicateFactory extends AbstractRoutePredicateFactory<BeforeRouteDemoPredicateFactory.Config> {
​
    private final static DateTimeFormatter DATE_TIME_FORMATTER = DateTimeFormatter.ofPattern("yyyy-MM-dd");
​
    public static final String CONFIG_KEY = "before";
​
    public BeforeRouteDemoPredicateFactory() {
        super(Config.class);
    }
​
    public Predicate<ServerWebExchange> apply(Config config) {
        return serverWebExchange -> {
            LocalDate now = LocalDate.now();
            return now.isAfter(config.getLocalDate());
        };
    }
​
    public static class Config {
        private LocalDate localDate;
​
        public LocalDate getLocalDate() {
            return localDate;
        }
​
        public void setLocalDate(String localDate) {
            this.localDate = LocalDate.parse(localDate, DATE_TIME_FORMATTER);
        }
    }
}

/**
* 在返回的response上加一个cookie
*/
public class AddResponseCookiesDemoFilterFactory extends AbstractGatewayFilterFactory<AbstractGatewayFilterFactory.NameConfig> {
​
    @Override
    public GatewayFilter apply(Consumer<NameConfig> consumer) {
        return apply(new NameConfig());
    }
​
    @Override
    public GatewayFilter apply(NameConfig config) {
        return (exchange, chain) -> chain.filter(exchange)
                .then(Mono.fromRunnable(()->{
                    ServerHttpResponse response = exchange.getResponse();
                    ResponseCookie cookie = ResponseCookie.from("custom.demo", "gateway-demo").build();
                    response.addCookie(cookie);
                }));
    }
}

@Configuration
@EnableConfigurationProperties(DemoAutoConfigProperties.class)
public class RouteExampleConfiguration {
​
    @Bean
    public BeforeRouteDemoPredicateFactory beforeRouteDemoPredicateFactory() {
        return new BeforeRouteDemoPredicateFactory();
    }
​
    @Bean
    public AddResponseCookiesDemoFilterFactory addResponseCookiesDemoFilterFactory() {
        return new AddResponseCookiesDemoFilterFactory();
    }
​
    @Bean
    public RouteLocator testRouteLocator(RouteLocatorBuilder locatorBuilder, DemoAutoConfigProperties properties) {
        BeforeRouteDemoPredicateFactory predicateFactory = beforeRouteDemoPredicateFactory();
        AddResponseCookiesDemoFilterFactory filterFactory = addResponseCookiesDemoFilterFactory();
​
        Predicate<ServerWebExchange> exchangePredicate = predicateFactory.apply(config -> config.setLocalDate(properties.getBefore()));
        GatewayFilter gatewayFilter = filterFactory.apply(config -> {
        });
        return locatorBuilder.routes()
                .route("demo.route",
                        r -> r.predicate(exchangePredicate)
                                .filters(f -> f.filter(gatewayFilter))
                                .uri(properties.getUri())
                ).build();
    }
}

demo:
  gateway:
    before: 2022-01-24
    uri: https://example.com

对Web请求进行拦截式、链式处理的契约，
这些请求可用于实现横切的、与应用程序无关的需求，如安全性、超时等。

@Component
public class CustomDynamic {
​
    //默认 InMemoryRouteDefinitionRepository
    @Autowired
    RouteDefinitionRepository routeDefinitionRepository;
​
    // 这样子引入的是: CompositeRouteDefinitionLocator; 组合了多个定位器
    @Autowired
    RouteDefinitionLocator routeDefinitionLocator;
​
    public void save(RouteDefinition routeDefinition) {
        Mono<RouteDefinition> definitionMono = Mono.just(routeDefinition);
        routeDefinitionRepository.save(definitionMono).block();
    }
​
    public Flux<RouteDefinition> list() {
        return routeDefinitionLocator.getRouteDefinitions();
    }
​
    public void delete(String routeId) {
        routeDefinitionRepository.delete(Mono.just(routeId)).block();
    }
​
}

@Component
public class DynamicRunner implements CommandLineRunner {
    @Autowired
    CustomDynamic customDynamic;
    @Autowired
    ApplicationEventPublisher publisher;
    @Override
    public void run(String... args) throws Exception {
        Flux<RouteDefinition> list = customDynamic.list();
        list.subscribe(System.out::println);

        customDynamic.save(buildSimpleRouteDefinition());

        TimeUnit.SECONDS.sleep(30);
        publisher.publishEvent(new RefreshRoutesEvent(this));
    }

    public RouteDefinition buildSimpleRouteDefinition() {
        RouteDefinition routeDefinition = new RouteDefinition();
        routeDefinition.setId("dynamic.demo");
        routeDefinition.setOrder(0);
        routeDefinition.setUri(URI.create("https://example.com"));

        PredicateDefinition predicateDefinition = new PredicateDefinition();
        predicateDefinition.setName("After");
        Map<String, String> map = new HashMap<>();
        map.put("datetime", "2012-01-24T17:42:47.789-07:00[America/Denver]");
        predicateDefinition.setArgs(map);
        List<PredicateDefinition> definitionArrayList = new ArrayList<>();
        definitionArrayList.add(predicateDefinition);

        routeDefinition.setPredicates(definitionArrayList);
        return routeDefinition;
    }
}