When the request comes, how does RouteDefinition convert to Route

[Maybrittnelson]

	@Override
	public Mono<Void> handle(ServerWebExchange exchange) {
		if (this.handlerMappings == null) {
			return createNotFoundError();
		}
		return Flux.fromIterable(this.handlerMappings)
				.concatMap(mapping -> mapping.getHandler(exchange))//1 
				.next()
				.switchIfEmpty(createNotFoundError())
				.flatMap(handler -> invokeHandler(exchange, handler))//2
				.flatMap(result -> handleResult(exchange, result));
	}

[Maybrittnelson]

getHandler

1. org.springframework.web.reactive.DispatcherHandler#handle
2. org.springframework.web.reactive.handler.AbstractHandlerMapping#getHandler
3. org.springframework.cloud.gateway.handler.RoutePredicateHandlerMapping#getHandlerInternal
4. org.springframework.cloud.gateway.handler.RoutePredicateHandlerMapping#lookupRoute

exchange.getAttributes().put(GATEWAY_PREDICATE_ROUTE_ATTR, r.getId());

5. CachingRouteLocator.getRoutes->CachingRouteLocator.delegate.getRoutes

//为什么是CachingRouteLocator  @Primary
	@Bean
	@Primary
	//TODO: property to disable composite?
	public RouteLocator cachedCompositeRouteLocator(List<RouteLocator> routeLocators) {
		return new CachingRouteLocator(new CompositeRouteLocator(Flux.fromIterable(routeLocators)));
	}
	
	@Bean
	public RoutePredicateHandlerMapping routePredicateHandlerMapping(
			FilteringWebHandler webHandler, **RouteLocator routeLocator**,
			GlobalCorsProperties globalCorsProperties, Environment environment) {
		return new RoutePredicateHandlerMapping(webHandler, routeLocator,
				globalCorsProperties, environment);
	}

6. CompositeRouteLocator.getRoutes
7. RouteDefinitionRouteLocator.getRoutes->routeDefinitionLocator
8. DiscoveryClientRouteDefinitionLocator.getRouteDefinitions
9. PropertiesRouteDefinitionLocator.getRouteDefinitions
10. RouteDefinitionRepository.getRouteDefinitions(InMemoryRouteDefinitionRepository)

[Maybrittnelson]

invokeHandler

1. org.springframework.web.reactive.DispatcherHandler#invokeHandler
2. org.springframework.web.reactive.result.SimpleHandlerAdapter#handle
3. org.springframework.cloud.gateway.handler.FilteringWebHandler#handle

Route route = exchange.getRequiredAttribute(GATEWAY_ROUTE_ATTR);

[Maybrittnelson]

补充rxjava，predicate的具体过程

1. concatmap
2. return r.getPredicate().apply(exchange);