背景

在springboot+tomcat应用中获取request对象可以使用RequestContextHolder.getRequestAttributes()的方式来获取，此种方式的核心在于request所在容器被放在threadlocal中，但是webflux结合netty项目却不能这么使用，因为webflux是异步响应式的，下面介绍下异步服务webflux+netty如何便捷获取request。

编写基于webflux的RequestContextHolder实现

1. 编写ReactiveHttpContextHolder类用来模拟RequestContextHolder

public class ReactiveHttpContextHolder {
    //获取当前请求对象
    public static Mono<ServerHttpRequest> getRequest() {
        return Mono.subscriberContext()
                .map(context -> context.get(Info.CONTEXT_KEY).getRequest());
    }

    //获取当前response
    public static Mono<ServerHttpResponse> getResponse(){
        return Mono.subscriberContext()
                .map(context -> context.get(Info.CONTEXT_KEY).getResponse());
    }

    public static final class Info{
        public static final Class<ServerWebExchange> CONTEXT_KEY = ServerWebExchange.class;
    }
}

2. 编写过滤器类用于设置request到容器中

@Component
@ConditionalOnWebApplication(type = ConditionalOnWebApplication.Type.REACTIVE)
public class AppFilter implements WebFilter {

    @Override
    public Mono<Void> filter(ServerWebExchange exchange, WebFilterChain chain) {
        //设置当前请求
         return chain.filter(exchange)
                .subscriberContext(context -> context.put(ReactiveHttpContextHolder.Info.CONTEXT_KEY, exchange));
    }
}

编写切面实现token拦截，校验权限

1. 切面逻辑代码

@Component
@Aspect
public class AuthAspect extends BaseController {

    @Pointcut("execution(public * xx.xx.xxController.*(..))")
    private void classRule(){}
    //带有AuthIgnore注解的不校验
    @Pointcut("@annotation(xx.AuthIgnore)")
    private void ignoreRule(){}

    @Around("classRule() && !ignoreRule()")
    public Mono<Object> aroundInvoke(ProceedingJoinPoint joinPoint){
        //获取token
        Mono<ServerHttpRequest> requestMono = ReactiveHttpContextHolder.getRequest();
        return requestMono.flatMap(request -> {
            //检查token
            String token = getHeader("token", request);
            if (token == null || TokenCacheContainer.getTokenCache().get(token) == null){
                BusException ex = new BusException("01300001");
                return buildErrMsg(ex);
            } else {
                try {
                    return (Mono<Object>) joinPoint.proceed();
                } catch (Throwable throwable) {
                    LogFactory.getLog(AuthAspect.class).error("", throwable);
                    BusException ex = new BusException("01300000");
                    return buildErrMsg(ex);
                }
            }
        });
    }

    private Mono<String> buildErrMsg(BusException ex){
        ApiJsonResult errResult = ApiJsonResult.createErrResult(ex.getErrorCode(), ex.getReason(), ex.getResolve());
        return Mono.just( errResult.toString() );
    }
}

2. 说明
   过滤器会在切面之前执行，因此aop中能获取到在filter中设置的request
3. 测试结果