org.springframework.cloud.gateway.filter.LoadBalancerClientFilter.java Source code

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Here is the source code for org.springframework.cloud.gateway.filter.LoadBalancerClientFilter.java

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/*
 * Copyright 2013-2017 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 */

package org.springframework.cloud.gateway.filter;

import java.net.URI;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.cloud.client.ServiceInstance;
import org.springframework.cloud.client.loadbalancer.LoadBalancerClient;
import org.springframework.cloud.gateway.support.NotFoundException;
import org.springframework.core.Ordered;
import org.springframework.web.server.ServerWebExchange;
import org.springframework.web.server.WebFilterChain;
import org.springframework.web.util.UriComponentsBuilder;

import static org.springframework.cloud.gateway.support.ServerWebExchangeUtils.GATEWAY_REQUEST_URL_ATTR;
import static org.springframework.cloud.gateway.support.ServerWebExchangeUtils.getAttribute;

import reactor.core.publisher.Mono;

/**
 * @author Spencer Gibb
 */
public class LoadBalancerClientFilter implements GlobalFilter, Ordered {

    private static final Log log = LogFactory.getLog(LoadBalancerClientFilter.class);
    public static final int LOAD_BALANCER_CLIENT_FILTER_ORDER = 10100;

    private final LoadBalancerClient loadBalancer;

    public LoadBalancerClientFilter(LoadBalancerClient loadBalancer) {
        this.loadBalancer = loadBalancer;
    }

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

    @Override
    public Mono<Void> filter(ServerWebExchange exchange, WebFilterChain chain) {
        URI url = getAttribute(exchange, GATEWAY_REQUEST_URL_ATTR, URI.class);
        if (url == null || !url.getScheme().equals("lb")) {
            return chain.filter(exchange);
        }
        log.trace("LoadBalancerClientFilter url before: " + url);

        final ServiceInstance instance = loadBalancer.choose(url.getHost());

        if (instance == null) {
            throw new NotFoundException("");
        }

        URI requestUrl = UriComponentsBuilder.fromUri(url).scheme(instance.isSecure() ? "https" : "http") //TODO: support websockets
                .host(instance.getHost()).port(instance.getPort()).build(true).toUri();
        log.trace("LoadBalancerClientFilter url chosen: " + requestUrl);
        exchange.getAttributes().put(GATEWAY_REQUEST_URL_ATTR, requestUrl);
        return chain.filter(exchange);
    }

}