SPRING CLOUD服务网关之ZUUL

服务网关是微服务架构中一个不可或缺的部分。通过服务网关统一向外系统提供REST API的过程中，除了具备服务路由、均衡负载功能之外，它还具备了权限控制等功能。Spring Cloud Netflix中的Zuul就担任了这样的一个角色，为微服务架构提供了前门保护的作用，同时将权限控制这些较重的非业务逻辑内容迁移到服务路由层面，使得服务集群主体能够具备更高的可复用性和可测试性。

pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.packtpub</groupId>
    <artifactId>Zuul</artifactId>
    <version>1.0.0</version>
    <packaging>jar</packaging>

    <name>Zuul</name>
    <description>com.packtpub.Zuul</description>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.5.2.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <java.version>1.8</java.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-zuul</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-eureka</artifactId>
        </dependency>
    </dependencies>
    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-dependencies</artifactId>
                <version>Camden.SR6</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

</project>

application.properties

spring.application.name=api-gateway
server.port=5555

zuul.routes.api-b.path=/compute-service/**
zuul.routes.api-b.serviceId=compute-service
eureka.client.serviceUrl.defaultZone=http://localhost:1111/eureka/

AccessFilter.java

package com.packtpub.Zuul;

import javax.servlet.http.HttpServletRequest;

import org.apache.log4j.Logger;
import org.apache.log4j.spi.LoggerFactory;

import com.netflix.zuul.ZuulFilter;
import com.netflix.zuul.context.RequestContext;

public class AccessFilter extends ZuulFilter {

    @Override
    public String filterType() {
        return "pre";
    }
    @Override
    public int filterOrder() {
        return 0;
    }
    @Override
    public boolean shouldFilter() {
        return true;
    }
    @Override
    public Object run() {
        RequestContext ctx = RequestContext.getCurrentContext();
        HttpServletRequest request = ctx.getRequest();

        Object accessToken = request.getParameter("accessToken");
        if(accessToken == null) {

            ctx.setSendZuulResponse(false);
            ctx.setResponseStatusCode(401);
            return null;
        }
        return null;
    }

}

ZuulApplication.java

package com.packtpub.Zuul;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.SpringCloudApplication;
import org.springframework.cloud.netflix.zuul.EnableZuulProxy;
import org.springframework.context.annotation.Bean;

@EnableZuulProxy
@SpringCloudApplication
public class ZuulApplication {

    public static void main(String[] args) {
        SpringApplication.run(ZuulApplication.class, args);
    }

    @Bean
    public AccessFilter accessFilter() {
        return new AccessFilter();
    }
}