网关

1.网关路由

1.1认识网关

网关：网络关口，负责请求的路由，转发，身份校验

1.2快速入门

1.2.1 引入依赖

<!--网关--> 
<dependency> 
    <groupId>org.springframework.cloud</groupId> 
    <artifactId>spring-cloud-starter-gateway</artifactId> 
</dependency>
<!--负载均衡--> 
<dependency> 
    <groupId>org.springframework.cloud</groupId> 
    <artifactId>spring-cloud-starter-loadbalancer</artifactId> 
</dependency>

1.2.2 配置路由

spring:
  application:
    name: gateway
  cloud:
    nacos:
      server-addr: 192.168.150.101:8848
    gateway:
      routes:
        - id: item # 路由规则id，自定义，唯一
          uri: lb://item-service # 路由的目标服务，lb代表负载均衡，会从注册中心拉取服务列表
          predicates: # 路由断言，判断当前请求是否符合当前规则，符合则路由到目标服务
            - Path=/items/**,/search/** # 这里是以请求路径作为判断规则
        - id: cart
          uri: lb://cart-service
          predicates:
            - Path=/carts/**

2.网关登录校验

2.1 思路分析

2.2 登录校验

在网关中编写过滤器

@Component
@RequiredArgsConstructor
public class AuthGlobalFilter implements GlobalFilter, Ordered {

    private final AuthProperties authProperties; //路径 /user/**,/login/**
    private final JwtTool jwtTool;
    private final AntPathMatcher antPathMatcher;

    @Override
    public Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) {
        //1.获取请求
        ServerHttpRequest request = exchange.getRequest();

        //2.判断是否需要登录拦截
        if (isExclude(request.getPath().toString())){
            return chain.filter(exchange);
        }
        //3.获取token
        String token=null;
        List<String> headers = request.getHeaders().get("authorization");
        if (headers!=null && !headers.isEmpty()){
            token=headers.get(0);
        }
        //4.校验并解析token
        Long userId=null;
        try {
            userId = jwtTool.parseToken(token);
        } catch (Exception e) {
            ServerHttpResponse response = exchange.getResponse();
            response.setStatusCode(HttpStatus.UNAUTHORIZED);
            //终止请求
            return  response.setComplete();
        }
        //5.传递用户信息
        String string = userId.toString();
        ServerWebExchange swe = exchange.mutate()
                .request(builder -> builder.header("user-info", string))
                .build();
        return chain.filter(swe);
    }

    private boolean isExclude(String path) {
        List<String> excludePaths = authProperties.getExcludePaths();
        for (String excludePath : excludePaths) {
            if(antPathMatcher.match(excludePath,path)){
                return true;
            }
        }
        return false;
    }

    @Override
    public int getOrder() {
        return 0;
    }
}

3.网关传递用户信息

3.1在微服务中编写拦截器

public class UserInfoInterceptor implements HandlerInterceptor {
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        String userInfo = request.getHeader("user-info");
        if (StrUtil.isNotBlank(userInfo)){
            UserContext.setUser(Long.valueOf(userInfo));
        }
        return true;
    }

    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
        UserContext.removeUser();
    }
}

3.2 在微服务中注册拦截器

@Configuration
@ConditionalOnClass(DispatcherServlet.class)
public class MvcConfig implements WebMvcConfigurer {

    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        registry.addInterceptor(new UserInfoInterceptor());
    }
}

4.微服务之间传递用户信息

下单的过程中，需要调用商品服务扣减库存，调用购物车服务清理用户购物车。而清理购物车时必须知道当前登录的用户身份。但是，订单服务调用购物车时并没有传递用户信息，购物车服务无法知道当前用户是谁！

由于微服务获取用户信息是通过拦截器在请求头中读取，因此要想实现微服务之间的用户信息传递，就必须在微服务发起调用时把用户信息存入请求头。

微服务之间调用是基于OpenFeign来实现的，并不是我们自己发送的请求。我们如何才能让每一个由OpenFeign发起的请求自动携带登录用户信息呢？

这里要借助Feign中提供的一个拦截器接口：feign.RequestInterceptor

4.1OpenFeign模块中编写拦截器

public class DefaultFeignConfig {

    @Bean
    public Logger.Level fullFeignLoggerLevel(){
        return Logger.Level.FULL;
    }

    @Bean
    public RequestInterceptor requestInterceptor(){
        return new RequestInterceptor() {
            @Override
            public void apply(RequestTemplate template) {
                Long user = UserContext.getUser();
                if (user!=null){
                    template.header("user-info", user.toString());
                }

            }
        };
    }
    @Bean
    public ItemClientFallbackFactory itemClientFallbackFactory(){
        return new ItemClientFallbackFactory();
    }
}

4.2微服务在启动类上添加

@EnableFeignClients(clients = {ItemClient.class, CartClient.class},defaultConfiguration = DefaultFeignConfig.class)
public class TradeApplication {
    public static void main(String[] args) {
        SpringApplication.run(TradeApplication.class,args);
    }
}