SpringCloud Gateway中你不知道的骚操作

Java学习录

发布于 2019-12-03 16:35:55

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发布于 2019-12-03 16:35:55

文章被收录于专栏：Java学习录

之前的几篇文章中，我们已经提到了如何使用SpringCloud Gateway，那几篇文章的内容已经足够做普通项目使用了，但是如果你想深入了解这个东西，或者说是看完这篇文章你用起来跟普通人就完全不是一个等级的了

路由谓语工厂的骚操作

AfterRoutePredicateFactory

前置时间路由工厂，匹配当前时间发生后的请求

spring:
  cloud:
    gateway:
      routes:
      - id: after_route
        uri: http://example.org
        predicates:
        - After=2017-01-20T17:42:47.789-07:00[America/Denver]

BeforeRoutePredicateFactory

后置时间路由工厂，匹配当前时间发生之前的请求

spring:
  cloud:
    gateway:
      routes:
      - id: before_route
        uri: http://example.org
        predicates:
        - Before=2017-01-20T17:42:47.789-07:00[America/Denver]

BetweenRoutePredicateFactory

匹配时间段的路由谓语工厂

spring:
  cloud:
    gateway:
      routes:
      - id: between_route
        uri: http://example.org
        predicates:
        - Betweeen=2017-01-20T17:42:47.789-07:00[America/Denver], 2017-01-21T17:42:47.789-07:00[America/Denver]

这个谓语工厂的判断逻辑如下：

 public Predicate<ServerWebExchange> apply(Config config) {
        ZonedDateTime datetime1 = getZonedDateTime(config.datetime1);
        ZonedDateTime datetime2 = getZonedDateTime(config.datetime2);
        Assert.isTrue(datetime1.isBefore(datetime2),
                config.datetime1 +
                " must be before " + config.datetime2);
        return exchange -> {
            final ZonedDateTime now = ZonedDateTime.now();
            return now.isAfter(datetime1) && now.isBefore(datetime2);
        };
    }

CookieRoutePredicateFactory

匹配请求cookie的路由谓语工厂

spring:
  cloud:
    gateway:
      routes:
      - id: cookie_route
        uri: http://example.org
        predicates:
        - Cookie=chocolate, ch.p

判断逻辑如下：

 public Predicate<ServerWebExchange> apply(Config config) {
        return exchange -> {
            List<HttpCookie> cookies = exchange.getRequest().getCookies().get(config.name);
            if (cookies == null) {
                return false;
            }
            for (HttpCookie cookie : cookies) {
                if (cookie.getValue().matches(config.regexp)) {
                    return true;
                }
            }
            return false;
        };
    }

HeaderRoutePredicateFactory

匹配请求header的路由谓语工厂

spring:
  cloud:
    gateway:
      routes:
      - id: header_route
        uri: http://example.org
        predicates:
        - Header=X-Request-Id, \d+

实现逻辑如下：

  public Predicate<ServerWebExchange> apply(Config config) {
        return exchange -> {
            List<String> values = exchange.getRequest().getHeaders().get(config.header);
            if (values != null) {
                for (String value : values) {
                    if (value.matches(config.regexp)) {
                        return true;
                    }
                }
            }
            return false;
        };
    }

HostRoutePredicateFactory

匹配请求host的路由谓语工厂

spring:
  cloud:
    gateway:
      routes:
      - id: host_route
        uri: http://example.org
        predicates:
        - Host=**.somehost.org

实现逻辑如下：

  public Predicate<ServerWebExchange> apply(Config config) {
        return exchange -> {
            String host = exchange.getRequest().getHeaders().getFirst("Host");
            return this.pathMatcher.match(config.getPattern(), host);
        };
    }

MethodRoutePredicateFactory

匹配请求method的路由谓语工厂

spring:
  cloud:
    gateway:
      routes:
      - id: method_route
        uri: http://example.org
        predicates:
        - Method=GET

实现逻辑如下：

    public Predicate<ServerWebExchange> apply(Config config) {
        return exchange -> {
            HttpMethod requestMethod = exchange.getRequest().getMethod();
            return requestMethod == config.getMethod();
        };
    }

PathRoutePredicateFactory

匹配请求路径的路由谓语工厂

spring:
  cloud:
    gateway:
      routes:
      - id: host_route
        uri: http://example.org
        predicates:
        - Path=/foo/{segment}

实现逻辑如下：

    public Predicate<ServerWebExchange> apply(Config config) {
        synchronized (this.pathPatternParser) {
            config.pathPattern = this.pathPatternParser.parse(config.pattern);
        }
        return exchange -> {
            PathContainer path = parsePath(exchange.getRequest().getURI().getPath());

            boolean match = config.pathPattern.matches(path);
            traceMatch("Pattern", config.pathPattern.getPatternString(), path, match);
            if (match) {
                PathMatchInfo uriTemplateVariables = config.pathPattern.matchAndExtract(path);
                exchange.getAttributes().put(URI_TEMPLATE_VARIABLES_ATTRIBUTE, uriTemplateVariables);
                return true;
            } else {
                return false;
            }
        };
    }

QueryRoutePredicateFactory

匹配请求参数的路由谓语工厂

spring:
  cloud:
    gateway:
      routes:
      - id: query_route
        uri: http://example.org
        predicates:
        - Query=foo, ba.

实现逻辑如下：

    public Predicate<ServerWebExchange> apply(Config config) {
        return exchange -> {
            if (!StringUtils.hasText(config.regexp)) {
                // check existence of header
                return exchange.getRequest().getQueryParams().containsKey(config.param);
            }
            List<String> values = exchange.getRequest().getQueryParams().get(config.param);
            for (String value : values) {
                if (value.matches(config.regexp)) {
                    return true;
                }
            }
            return false;
        };
    }

RemoteAddrRoutePredicateFactory

匹配远程地址的路由谓语工厂

spring:
  cloud:
    gateway:
      routes:
      - id: remoteaddr_route
        uri: http://example.org
        predicates:
        - RemoteAddr=192.168.1.1/24

实现逻辑如下：

    public Predicate<ServerWebExchange> apply(Config config) {
        List<IpSubnetFilterRule> sources = convert(config.sources);

        return exchange -> {
            InetSocketAddress remoteAddress = config.remoteAddressResolver.resolve(exchange);
            if (remoteAddress != null) {
                String hostAddress = remoteAddress.getAddress().getHostAddress();
                String host = exchange.getRequest().getURI().getHost();

                if (log.isDebugEnabled() && !hostAddress.equals(host)) {
                    log.debug("Remote addresses didn't match " + hostAddress + " != " + host);
                }

                for (IpSubnetFilterRule source : sources) {
                    if (source.matches(remoteAddress)) {
                        return true;
                    }
                }
            }

            return false;
        };
    }

拦截器的骚操作

AddRequestHeaderGatewayFilterFactory

为请求中添加header的拦截器

spring:
  cloud:
    gateway:
      routes:
      - id: add_request_header_route
        uri: http://example.org
        filters:
        - AddRequestHeader=X-Request-Foo, Bar

实现逻辑如下：

    public GatewayFilter apply(NameValueConfig config) {
        return (exchange, chain) -> {
            ServerHttpRequest request = exchange.getRequest().mutate()
                    .header(config.getName(), config.getValue())
                    .build();

            return chain.filter(exchange.mutate().request(request).build());
        };
    }

AddRequestParameterGatewayFilterFactory

为请求中添加请求参数的拦截器

spring:
  cloud:
    gateway:
      routes:
      - id: add_request_parameter_route
        uri: http://example.org
        filters:
        - AddRequestParameter=foo, bar

实现逻辑如下：

    public GatewayFilter apply(NameValueConfig config) {
        return (exchange, chain) -> {
            URI uri = exchange.getRequest().getURI();
            StringBuilder query = new StringBuilder();
            String originalQuery = uri.getRawQuery();

            if (StringUtils.hasText(originalQuery)) {
                query.append(originalQuery);
                if (originalQuery.charAt(originalQuery.length() - 1) != '&') {
                    query.append('&');
                }
            }

            //TODO urlencode?
            query.append(config.getName());
            query.append('=');
            query.append(config.getValue());

            try {
                URI newUri = UriComponentsBuilder.fromUri(uri)
                        .replaceQuery(query.toString())
                        .build(true)
                        .toUri();

                ServerHttpRequest request = exchange.getRequest().mutate().uri(newUri).build();

                return chain.filter(exchange.mutate().request(request).build());
            } catch (RuntimeException ex) {
                throw new IllegalStateException("Invalid URI query: \"" + query.toString() + "\"");
            }
        };
    }

AddResponseHeaderGatewayFilterFactory

为响应中添加header的拦截器

spring:
  cloud:
    gateway:
      routes:
      - id: add_request_header_route
        uri: http://example.org
        filters:
        - AddResponseHeader=X-Response-Foo, Bar

实现逻辑如下：

public GatewayFilter apply(NameValueConfig config) {
        return (exchange, chain) -> {
            exchange.getResponse().getHeaders().add(config.getName(), config.getValue());

            return chain.filter(exchange);
        };
    }

HystrixGatewayFilterFactory

服务熔断的拦截器

spring:
  cloud:
    gateway:
      routes:
      - id: hytstrix_route
        uri: http://example.org
        filters:
        - Hystrix=myCommandName
          args:
            name: default
            fallbackUri: forward:/defaultfallback

实现逻辑如下，建议搭配之前的Hystrix源码解析阅读

    public GatewayFilter apply(Config config) {
        //TODO: if no name is supplied, generate one from command id (useful for default filter)
        if (config.setter == null) {
            Assert.notNull(config.name, "A name must be supplied for the Hystrix Command Key");
            HystrixCommandGroupKey groupKey = HystrixCommandGroupKey.Factory.asKey(getClass().getSimpleName());
            HystrixCommandKey commandKey = HystrixCommandKey.Factory.asKey(config.name);

            config.setter = Setter.withGroupKey(groupKey)
                    .andCommandKey(commandKey);
        }

        return (exchange, chain) -> {
            RouteHystrixCommand command = new RouteHystrixCommand(config.setter, config.fallbackUri, exchange, chain);

            return Mono.create(s -> {
                Subscription sub = command.toObservable().subscribe(s::success, s::error, s::success);
                s.onCancel(sub::unsubscribe);
            }).onErrorResume((Function<Throwable, Mono<Void>>) throwable -> {
                if (throwable instanceof HystrixRuntimeException) {
                    HystrixRuntimeException e = (HystrixRuntimeException) throwable;
                    if (e.getFailureType() == TIMEOUT) { //TODO: optionally set status
                        setResponseStatus(exchange, HttpStatus.GATEWAY_TIMEOUT);
                        return exchange.getResponse().setComplete();
                    }
                }
                return Mono.error(throwable);
            }).then();
        };
    }

PrefixPathGatewayFilterFactory

为请求路径添加前缀的拦截器

spring:
  cloud:
    gateway:
      routes:
      - id: prefixpath_route
        uri: http://example.org
        filters:
        - PrefixPath=/mypath

实现逻辑如下：

    public GatewayFilter apply(Config config) {
        return (exchange, chain) -> {

            boolean alreadyPrefixed = exchange.getAttributeOrDefault(GATEWAY_ALREADY_PREFIXED_ATTR, false);
            if (alreadyPrefixed) {
                return chain.filter(exchange);
            }
            exchange.getAttributes().put(GATEWAY_ALREADY_PREFIXED_ATTR, true);

            ServerHttpRequest req = exchange.getRequest();
            addOriginalRequestUrl(exchange, req.getURI());
            String newPath = config.prefix + req.getURI().getRawPath();

            ServerHttpRequest request = req.mutate()
                    .path(newPath)
                    .build();

            exchange.getAttributes().put(GATEWAY_REQUEST_URL_ATTR, request.getURI());

            if (log.isTraceEnabled()) {
                log.trace("Prefixed URI with: "+config.prefix+" -> "+request.getURI());
            }

            return chain.filter(exchange.mutate().request(request).build());
        };
    }

RequestRateLimiterGatewayFilterFactory

请求限流的拦截器

这个拦截器相比于上方的各个拦截器还是稍微复杂一点的。首先需要引入一个额外的包

<dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-redis-reactive</artifactId>
</dependency>

然后呢你要基于SpringBoot做好redis的自动装配，紧接着就是设置限流key，限流key的设置需要实现keyResolver接口，然后通过它的这个方法Mono resolve(ServerWebExchange exchange)返回你需要设置的限流key

配置的地方是这样的

spring:
  cloud:
    gateway:
      routes:
      - id: requestratelimiter_route
        uri: http://example.org
        filters:
        - RequestRateLimiter=10, 20, #{@userKeyResolver}

其中前两个参数分别是令牌桶算法的两个参数，填充速率和限流阈值，更多关于限流算法的操作可以参考我的这篇文章：大型网站限流算法的实现和改造

拦截器实现逻辑如下：

    public GatewayFilter apply(Config config) {
        KeyResolver resolver = (config.keyResolver == null) ? defaultKeyResolver : config.keyResolver;
        RateLimiter<Object> limiter = (config.rateLimiter == null) ? defaultRateLimiter : config.rateLimiter;

        return (exchange, chain) -> {
            Route route = exchange.getAttribute(ServerWebExchangeUtils.GATEWAY_ROUTE_ATTR);

            return resolver.resolve(exchange).flatMap(key ->
                    // TODO: if key is empty?
                    limiter.isAllowed(route.getId(), key).flatMap(response -> {

                        for (Map.Entry<String, String> header : response.getHeaders().entrySet()) {
                            exchange.getResponse().getHeaders().add(header.getKey(), header.getValue());
                        }

                        if (response.isAllowed()) {
                            return chain.filter(exchange);
                        }

                        exchange.getResponse().setStatusCode(config.getStatusCode());
                        return exchange.getResponse().setComplete();
                    }));
        };
    }

RedirectToGatewayFilterFactory

请求重定向的拦截器

spring:
  cloud:
    gateway:
      routes:
      - id: prefixpath_route
        uri: http://example.org
        filters:
        - RedirectTo=302, http://acme.org

实现逻辑如下：

    public GatewayFilter apply(String statusString, String urlString) {
        final HttpStatus httpStatus = parse(statusString);
        Assert.isTrue(httpStatus.is3xxRedirection(), "status must be a 3xx code, but was " + statusString);
        final URL url;
        try {
            url = URI.create(urlString).toURL();
        } catch (MalformedURLException e) {
            throw new IllegalArgumentException("Invalid url " + urlString, e);
        }
        return apply(httpStatus, url);
    }

RemoveRequestHeaderGatewayFilterFactory/RemoveResponseHeaderGatewayFilterFactory

删除请求、响应中的header拦截器

spring:
  cloud:
    gateway:
      routes:
      - id: removerequestheader_route
        uri: http://example.org
        filters:
        - RemoveRequestHeader=X-Request-Foo

实现逻辑这里就贴其中一个了：

    public GatewayFilter apply(NameConfig config) {
        return (exchange, chain) -> {
            ServerHttpRequest request = exchange.getRequest().mutate()
                    .headers(httpHeaders -> httpHeaders.remove(config.getName()))
                    .build();

            return chain.filter(exchange.mutate().request(request).build());
        };
    }

RewritePathGatewayFilterFactory

重写请求路径的拦截器

spring:
  cloud:
    gateway:
      routes:
      - id: rewritepath_route
        uri: http://example.org
        predicates:
        - Path=/foo/**
        filters:
        - RewritePath=/foo/

实现逻辑如下：

  public GatewayFilter apply(Config config) {
        String replacement = config.replacement.replace("$\\", "$");
        return (exchange, chain) -> {
            ServerHttpRequest req = exchange.getRequest();
            addOriginalRequestUrl(exchange, req.getURI());
            String path = req.getURI().getRawPath();
            String newPath = path.replaceAll(config.regexp, replacement);

            ServerHttpRequest request = req.mutate()
                    .path(newPath)
                    .build();

            exchange.getAttributes().put(GATEWAY_REQUEST_URL_ATTR, request.getURI());

            return chain.filter(exchange.mutate().request(request).build());
        };
    }

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原始发表：2019-11-29，如有侵权请联系 cloudcommunity@tencent.com 删除

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