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本文主要基于 Spring-Cloud-Gateway 2.0.X M4


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1. 概述

本文主要分享 GatewayFilterFactory 的实现类

GatewayFilterFactory 实现类较多,根据用途整理如下脑图 :

下面我们开始逐块解析源码实现。


推荐 Spring Cloud 书籍

2. Header

本小节分享 Header 相关的 GatewayFilterFactory 实现类。

2.1 AddRequestHeaderGatewayFilterFactory

  • 用途 :添加指定请求 Header 为指定值。
  • 配置 :

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

    1: public class AddRequestHeaderGatewayFilterFactory implements GatewayFilterFactory {
    2:
    3: @Override
    4: public List<String> argNames() {
    5: return Arrays.asList(NAME_KEY, VALUE_KEY);
    6: }
    7:
    8: @Override
    9: public GatewayFilter apply(Tuple args) {
    10: String name = args.getString(NAME_KEY);
    11: String value = args.getString(VALUE_KEY);
    12:
    13: return (exchange, chain) -> { // GatewayFilter
    14: // 创建新的 ServerHttpRequest
    15: ServerHttpRequest request = exchange.getRequest().mutate()
    16: .header(name, value)
    17: .build();
    18:
    19: // 创建新的 ServerWebExchange ,提交过滤器链继续过滤
    20: return chain.filter(exchange.mutate().request(request).build());
    21: };
    22: }
    23: }
    • Tuple 参数 :name / value
    • 第 14 至 17 行 :创建的 ServerHttpRequest 。
    • 第 19 至 20 行 :创建的 ServerWebExchange ,提交过滤器链继续过滤。

2.2 RemoveRequestHeaderGatewayFilterFactory

类似 AddRequestHeaderGatewayFilterFactory ,不重复分享,点击 《Spring Cloud Gateway —— RemoveRequestHeader GatewayFilter Factory》 查看官方文档。

2.3 AddResponseHeaderGatewayFilterFactory

类似 AddRequestHeaderGatewayFilterFactory ,不重复分享,点击 《Spring Cloud Gateway —— AddResponseHeader GatewayFilter Factory》 查看官方文档。

2.4 RemoveResponseHeaderGatewayFilterFactory

类似 AddRequestHeaderGatewayFilterFactory ,不重复分享,点击 《Spring Cloud Gateway —— RemoveResponseHeader GatewayFilter Factory》 查看官方文档。

2.5 SetResponseHeaderGatewayFilterFactory

类似 AddRequestHeaderGatewayFilterFactory ,不重复分享,点击 《Spring Cloud Gateway —— SetStatus GatewayFilter Factory》 查看官方文档。

2.6 RemoveNonProxyHeadersGatewayFilterFactory

  • 用途 :移除请求 Proxy 相关的 Header 。默认值为 [ "Connection", "Keep-Alive", "Proxy-Authenticate", "Proxy-Authorization", "TE", "Trailer", "Transfer-Encoding", "Upgrade" ] ( 参考自 :https://tools.ietf.org/html/draft-ietf-httpbis-p1-messaging-14#section-7.1.3 ) ,可以通过 spring.cloud.gateway.filter.remove-non-proxy-headers 配置。
  • 代码 :

    1: @ConfigurationProperties("spring.cloud.gateway.filter.remove-non-proxy-headers")
    2: public class RemoveNonProxyHeadersGatewayFilterFactory implements GatewayFilterFactory {
    3:
    4: /**
    5: * 默认
    6: */
    7: public static final String[] DEFAULT_HEADERS_TO_REMOVE = new String[] {"Connection", "Keep-Alive",
    8: "Proxy-Authenticate", "Proxy-Authorization", "TE", "Trailer", "Transfer-Encoding", "Upgrade"};
    9:
    10: private List<String> headers = Arrays.asList(DEFAULT_HEADERS_TO_REMOVE);
    11:
    12: public List<String> getHeaders() {
    13: return headers;
    14: }
    15:
    16: public void setHeaders(List<String> headers) {
    17: this.headers = headers;
    18: }
    19:
    20: @Override
    21: public GatewayFilter apply(Tuple args) {
    22: //TODO: support filter args
    23:
    24: return (exchange, chain) -> {
    25: // 创建新的 ServerHttpRequest
    26: ServerHttpRequest request = exchange.getRequest().mutate()
    27: .headers(httpHeaders -> {
    28: for (String header : this.headers) {
    29: httpHeaders.remove(header); // 移除
    30: }
    31: })
    32: .build();
    33:
    34: // 创建新的 ServerWebExchange ,提交过滤器链继续过滤
    35: return chain.filter(exchange.mutate().request(request).build());
    36: };
    37: }
    38:

2.7 SecureHeadersGatewayFilterFactory

  • 用途 :添加响应 Secure 相关的 Header 。默认值在 org.springframework.cloud.gateway.filter.factory.SecureHeadersProperties ,可以通过 spring.cloud.gateway.filter.secure-headers 配置。
  • 推荐文章 :
  • 代码 :

    1: public class SecureHeadersGatewayFilterFactory implements GatewayFilterFactory {
    2:
    3: public static final String X_XSS_PROTECTION_HEADER = "X-Xss-Protection";
    4: public static final String STRICT_TRANSPORT_SECURITY_HEADER = "Strict-Transport-Security";
    5: public static final String X_FRAME_OPTIONS_HEADER = "X-Frame-Options";
    6: public static final String X_CONTENT_TYPE_OPTIONS_HEADER = "X-Content-Type-Options";
    7: public static final String REFERRER_POLICY_HEADER = "Referrer-Policy";
    8: public static final String CONTENT_SECURITY_POLICY_HEADER = "Content-Security-Policy";
    9: public static final String X_DOWNLOAD_OPTIONS_HEADER = "X-Download-Options";
    10: public static final String X_PERMITTED_CROSS_DOMAIN_POLICIES_HEADER = "X-Permitted-Cross-Domain-Policies";
    11:
    12: private final SecureHeadersProperties properties;
    13:
    14: public SecureHeadersGatewayFilterFactory(SecureHeadersProperties properties) {
    15: this.properties = properties;
    16: }
    17:
    18: @Override
    19: public GatewayFilter apply(Tuple args) {
    20: //TODO: allow args to override properties
    21:
    22: return (exchange, chain) -> {
    23: HttpHeaders headers = exchange.getResponse().getHeaders();
    24:
    25: //TODO: allow header to be disabled
    26: headers.add(X_XSS_PROTECTION_HEADER, properties.getXssProtectionHeader());
    27: headers.add(STRICT_TRANSPORT_SECURITY_HEADER, properties.getStrictTransportSecurity());
    28: headers.add(X_FRAME_OPTIONS_HEADER, properties.getFrameOptions());
    29: headers.add(X_CONTENT_TYPE_OPTIONS_HEADER, properties.getContentTypeOptions());
    30: headers.add(REFERRER_POLICY_HEADER, properties.getReferrerPolicy());
    31: headers.add(CONTENT_SECURITY_POLICY_HEADER, properties.getContentSecurityPolicy());
    32: headers.add(X_DOWNLOAD_OPTIONS_HEADER, properties.getDownloadOptions());
    33: headers.add(X_PERMITTED_CROSS_DOMAIN_POLICIES_HEADER, properties.getPermittedCrossDomainPolicies());
    34:
    35: return chain.filter(exchange);
    36: };
    37: }
    38: }
    • 第 26 至 33 行 :添加响应 Secure 相关的 Header 。

3. Parameter

本小节分享 Parameter 相关的 GatewayFilterFactory 实现类。

3.1 AddRequestParameterGatewayFilterFactory

类似 AddRequestHeaderGatewayFilterFactory ,不重复分享,点击 《Spring Cloud Gateway —— AddRequestParameter GatewayFilter Factory》 查看官方文档。

4. Path

本小节分享 Path 相关的 GatewayFilterFactory 实现类。

4.1 RewritePathGatewayFilterFactory

  • 用途 :根据配置的正则表达式 regexp ,使用配置的 replacement 重写请求 Path 。从功能目的上类似 《Module ngx_http_rewrite_module》
  • 配置 :

    spring:
    cloud:
    gateway:
    routes:
    # =====================================
    - id: rewritepath_route
    uri: http://example.org
    predicates:
    - Path=/foo/**
    filters:
    - RewritePath=/foo/(?<segment>.*), /$\{segment}
    • 注意,$\ 用于替代 $ ,避免和 YAML 语法冲突。
  • 代码 :

    1: public class RewritePathGatewayFilterFactory implements GatewayFilterFactory {
    2:
    3: public static final String REGEXP_KEY = "regexp";
    4: public static final String REPLACEMENT_KEY = "replacement";
    5:
    6: @Override
    7: public List<String> argNames() {
    8: return Arrays.asList(REGEXP_KEY, REPLACEMENT_KEY);
    9: }
    10:
    11: @Override
    12: public GatewayFilter apply(Tuple args) {
    13: final String regex = args.getString(REGEXP_KEY);
    14: // `$\` 用于替代 `$` ,避免和 YAML 语法冲突。
    15: String replacement = args.getString(REPLACEMENT_KEY).replace("$\\", "$");
    16:
    17: return (exchange, chain) -> {
    18: ServerHttpRequest req = exchange.getRequest();
    19: // 添加 原始请求URI 到 GATEWAY_ORIGINAL_REQUEST_URL_ATTR
    20: addOriginalRequestUrl(exchange, req.getURI());
    21: // 重写 Path
    22: String path = req.getURI().getPath();
    23: String newPath = path.replaceAll(regex, replacement);
    24:
    25: // 创建新的 ServerHttpRequest
    26: ServerHttpRequest request = req.mutate()
    27: .path(newPath) // 设置 Path
    28: .build();
    29:
    30: // 添加 请求URI 到 GATEWAY_REQUEST_URL_ATTR
    31: exchange.getAttributes().put(GATEWAY_REQUEST_URL_ATTR, request.getURI());
    32:
    33: // 创建新的 ServerWebExchange ,提交过滤器链继续过滤
    34: return chain.filter(exchange.mutate().request(request).build());
    35: };
    36: }
    37: }
    • Tuple 参数 :regexp / replacement
    • 第 15 行 :$\ 用于替代 $ ,避免和 YAML 语法冲突。
    • 第 20 行 :调用 ServerWebExchangeUtils#addOriginalRequestUrl(...) 添加原始请求 URI 到 GATEWAY_ORIGINAL_REQUEST_URL_ATTR 。代码如下 :

      public static void addOriginalRequestUrl(ServerWebExchange exchange, URI url) {
      exchange.getAttributes().computeIfAbsent(GATEWAY_ORIGINAL_REQUEST_URL_ATTR, s -> new LinkedHashSet<>()); // 数组,考虑多次重写
      LinkedHashSet<URI> uris = exchange.getRequiredAttribute(GATEWAY_ORIGINAL_REQUEST_URL_ATTR);
      uris.add(url);
      }
      • 为什么使用 LinkedHashSet ?因为可以使用 RewritePathGatewayFilterFactory / PrefixPathGatewayFilterFactory 多次重写。
    • 第 21 至 23 行 :重写请求 Path 。

    • 第 26 至 28 行 :创建的 ServerHttpRequest 。
    • 第 31 行 :添加请求 URI 到 GATEWAY_REQUEST_URL_ATTR
    • 第 34 行 :创建的 ServerWebExchange ,提交过滤器链继续过滤。

4.2 PrefixPathGatewayFilterFactory

类似 RewritePathGatewayFilterFactory ,不重复分享,点击 《Spring Cloud Gateway —— PrefixPath GatewayFilter Factory》 查看官方文档。

4.3 SetPathGatewayFilterFactory

类似 RewritePathGatewayFilterFactory ,不重复分享,点击 《Spring Cloud Gateway —— SetPath GatewayFilter Factory》 查看官方文档。

5. Status

本小节分享 Status 相关的 GatewayFilterFactory 实现类。

5.1 SetStatusGatewayFilterFactory

类似 RedirectToGatewayFilterFactory ,不重复分享,点击 《Spring Cloud Gateway —— SetStatus GatewayFilter Factory》 查看官方文档。

6. Redirect

本小节分享 Redirect 相关的 GatewayFilterFactory 实现类。

6.1 RedirectToGatewayFilterFactory

  • 用途 :将响应重定向到指定 URL ,并设置响应状态码为指定 Status 。注意,Status 必须为 3XX 重定向状态码。
  • 配置 :

    spring:
    cloud:
    gateway:
    routes:
    # =====================================
    - id: prefixpath_route
    uri: http://example.org
    filters:
    - RedirectTo=302, http://www.iocoder.cn
  • 代码 :

    1: public class RedirectToGatewayFilterFactory implements GatewayFilterFactory {
    2:
    3: public static final String STATUS_KEY = "status";
    4: public static final String URL_KEY = "url";
    5:
    6: @Override
    7: public List<String> argNames() {
    8: return Arrays.asList(STATUS_KEY, URL_KEY);
    9: }
    10:
    11: @Override
    12: public GatewayFilter apply(Tuple args) {
    13: String statusString = args.getRawString(STATUS_KEY);
    14: String urlString = args.getString(URL_KEY);
    15:
    16: // 解析 status ,并判断是否是 3XX 重定向状态
    17: final HttpStatus httpStatus = parse(statusString);
    18: Assert.isTrue(httpStatus.is3xxRedirection(), "status must be a 3xx code, but was " + statusString);
    19: // 创建 URL
    20: final URL url;
    21: try {
    22: url = URI.create(urlString).toURL();
    23: } catch (MalformedURLException e) {
    24: throw new IllegalArgumentException("Invalid url " + urlString, e);
    25: }
    26:
    27: return (exchange, chain) ->
    28: chain.filter(exchange).then(Mono.defer(() -> { // After Filter
    29: if (!exchange.getResponse().isCommitted()) {
    30: // 设置响应 Status
    31: setResponseStatus(exchange, httpStatus);
    32:
    33: // 设置响应 Header
    34: final ServerHttpResponse response = exchange.getResponse();
    35: response.getHeaders().set(HttpHeaders.LOCATION, url.toString());
    36: return response.setComplete();
    37: }
    38: return Mono.empty();
    39: }));
    40: }
    41:
    42: }
    • 第 16 至 18 行 :解析配置的 statusString ,并判断是否是 3XX 重定向状态码。
    • 第 19 至 25 行 :解析配置的 urlString ,创建 URL 。
    • 第 28 行 :调用 #then(Mono) 方法,实现 After Filter 逻辑。这里和 AddRequestHeaderGatewayFilterFactory 实现的 Before Filter 【方式】不同
    • 第 29 至 37 行 :若响应未提交,设置响应的状态码、响应的 Header ( Location ) 。
    • 第 38 行 :设置响应已提交

7. Hystrix

熔断相关 GatewayFilter,我们在 《Spring-Cloud-Gateway 源码解析 —— 过滤器 (4.9) 之 HystrixGatewayFilterFactory 熔断》 详细解析。

8. RateLimiter

限流相关 GatewayFilter,我们在 《Spring-Cloud-Gateway 源码解析 —— 过滤器 (4.10) 之 RequestRateLimiterGatewayFilterFactory 请求限流》 详细解析。

666. 彩蛋

恩,稍显啰嗦的一篇文章,后面会比较精彩,你懂的。

胖友,分享一波朋友圈可好!

文章目录
  1. 1. 1. 概述
  2. 2. 2. Header
    1. 2.1. 2.1 AddRequestHeaderGatewayFilterFactory
    2. 2.2. 2.2 RemoveRequestHeaderGatewayFilterFactory
    3. 2.3. 2.3 AddResponseHeaderGatewayFilterFactory
    4. 2.4. 2.4 RemoveResponseHeaderGatewayFilterFactory
    5. 2.5. 2.5 SetResponseHeaderGatewayFilterFactory
    6. 2.6. 2.6 RemoveNonProxyHeadersGatewayFilterFactory
    7. 2.7. 2.7 SecureHeadersGatewayFilterFactory
  3. 3. 3. Parameter
    1. 3.1. 3.1 AddRequestParameterGatewayFilterFactory
  4. 4. 4. Path
    1. 4.1. 4.1 RewritePathGatewayFilterFactory
    2. 4.2. 4.2 PrefixPathGatewayFilterFactory
    3. 4.3. 4.3 SetPathGatewayFilterFactory
  5. 5. 5. Status
    1. 5.1. 5.1 SetStatusGatewayFilterFactory
  6. 6. 6. Redirect
    1. 6.1. 6.1 RedirectToGatewayFilterFactory
  7. 7. 7. Hystrix
  8. 8. 8. RateLimiter
  9. 9. 666. 彩蛋