SpringCloud系列之自定义GatewayFilterFactory

学习目的：

• 知道创建一个网关sample
• 知道网关的基本配置
• 知道自定义GatewayFilterFactory类

环境准备：

• JDK 1.8
• SpringBoot2.2.3
• SpringCloud(Hoxton.SR7)
• Maven 3.2+
• 开发工具
  • IntelliJ IDEA
  • smartGit

新增SpringBoot Initializer项目：New Module->Spring Initializer，选择jdk版本，至少jdk8

packaging选择jar，java version选择jdk8的，然后点next

选择Gateway的依赖，选择之后会自动加上对应pom配置

新建项目之后，检查pom是否有spring-cloud-starter-gateway

<dependency>
  <groupId>org.springframework.cloud</groupId>
  <artifactId>spring-cloud-starter-gateway</artifactId>
</dependency>

如果不通过idea的Spring Initializer新建项目的，需要自己加上：

<dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-dependencies</artifactId>
                <version>${spring-cloud.version}</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>

网关配置，业务场景，一个第三方的接口，经过网关路由之后需要在request header里加上一些校验参数

spring:
  application:
    name: api-gateway  # 指定application name
  cloud:
    gateway:
      routes:
        - id: get_user_info
          uri: http://127.0.0.1:8083
          predicates:
          - Path=/api/findUser
          filters:
          - AddRequestHeader=passToken,a68f3eac-5b9c-4fc1-a900-98ee18574576
          # FilterFactory名为自定义类名前几个
          - name: Custom
            args:
              passid: 7a11600c-403c-4260-9165-659e138ada9c
              serviceId: d8c6ce4c-1b2c-4826-9044-4197d17aad87

自定义一个GatewayFilterFactory，命名后面统一加上GatewayFilterFactory，自定义的字段配在yml的filters.name

package com.example.springcloud.gateway.filter.factories;

import com.example.springcloud.gateway.util.EncryptUtils;
import lombok.Data;
import lombok.extern.slf4j.Slf4j;
import org.springframework.cloud.gateway.filter.GatewayFilter;
import org.springframework.cloud.gateway.filter.factory.AbstractGatewayFilterFactory;
import org.springframework.core.Ordered;
import org.springframework.http.server.reactive.ServerHttpRequest;

import java.util.Date;

/**
 * <pre>
 *      自定义网关过滤器
 * </pre>
 *
 * <pre>
 * @author mazq
 * 修改记录
 *    修改后版本:     修改人：  修改日期: 2021/12/14 09:59  修改内容:
 * </pre>
 */
@Slf4j
public class CustomGatewayFilterFactory extends AbstractGatewayFilterFactory<CustomGatewayFilterFactory.Config>
implements Ordered {

    public CustomGatewayFilterFactory() {
        super(Config.class);
    }

    @Override
    public GatewayFilter apply(Config config) {
        return ((exchange, chain) -> {
            String passToken = exchange.getRequest().getHeaders().getFirst("passToken");
            log.info("passToken:{}" , passToken);
            long now = new Date().getTime();
            String timestamp = Long.toString((long)Math.floor(now/1000));
            String signature = "";
            try {
                signature = EncryptUtils.toSHA256(timestamp + passToken + timestamp);
            } catch (Exception e) {
                e.printStackTrace();
            }
            log.info("signature:{}" , signature);
            ServerHttpRequest request = exchange.getRequest().mutate()
                    .header("passid", config.getPassid())
                    .header("serviceId", config.getServiceId())
                    .header("signature", signature)
                    .build();
            log.info("passid:{}" , config.getPassid());
            log.info("serviceId:{}" , config.getServiceId());
            return chain.filter(exchange.mutate().request(request).build());
        });
    }

    @Override
    public int getOrder() {
        return Ordered.HIGHEST_PRECEDENCE;
    }


    @Data
    public static class Config {
        private String passid;
        private String serviceId;
    }
}

过滤器将在较早的阶段执行其“pre”逻辑，但稍后会调用它的“post”实现：

官网的图例：首先客户端请求都会先经过Gateway Handler Mapping，匹配上就通过Gateway Web Handler转给过滤器处理，过滤器分为PreFilter（前置过滤器）、PostFilter（后置过滤器）。过滤器由虚线分隔的原因是，筛选器可以在发送代理请求之前和之后运行逻辑。所有“前置”过滤器逻辑均被执行。然后发出代理请求。发出代理请求后，将运行“后置”过滤器逻辑

import java.security.MessageDigest;

/**
 *	<pre>
 *	    加密工具类
 *	</pre>
 */
public class EncryptUtils {

	/**
	 * 	sha256签名算法
	 */
	public static String toSHA256(String str) throws Exception {
		MessageDigest messageDigest;
		String encodeStr = "";
		try {
			messageDigest = MessageDigest.getInstance("SHA-256");
			messageDigest.update(str.getBytes("UTF-8"));
			encodeStr = byte2Hex(messageDigest.digest());
		} catch (Exception e) {
			throw e;
		}
		return encodeStr;
	}

	/**
	 * byte转换成16进制
	 */
	protected static String byte2Hex(byte[] bytes) {
		StringBuffer stringBuffer = new StringBuffer();
		String temp = null;
		for (int i = 0; i < bytes.length; i++) {
			temp = Integer.toHexString(bytes[i] & 0xFF);
			if (temp.length() == 1) {
				stringBuffer.append("0");
			}
			stringBuffer.append(temp);
		}
		return stringBuffer.toString();
	}
}

控制台打印：

signature:72bdd60d2fc6f115eabda1ced766c0c0aa7397521d653977b2fd15d6c6978587
passid:7a11600c-403c-4260-9165-659e138ada9c
serviceId:d8c6ce4c-1b2c-4826-9044-4197d17aad87

然后去第三方接口看请求header参数，可以带过来

注意：如果网关配置不起效，可以尝试设置ordered确定优先级，有多个配置，可以将配置位置适当挪前点