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

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

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/*
 * Copyright 2013-2019 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
 *
 *      https://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 reactor.core.publisher.Mono;

import org.springframework.beans.factory.ObjectProvider;
import org.springframework.core.Ordered;
import org.springframework.web.reactive.DispatcherHandler;
import org.springframework.web.server.ServerWebExchange;

import static org.springframework.cloud.gateway.support.ServerWebExchangeUtils.GATEWAY_REQUEST_URL_ATTR;
import static org.springframework.cloud.gateway.support.ServerWebExchangeUtils.isAlreadyRouted;
import static org.springframework.cloud.gateway.support.ServerWebExchangeUtils.setAlreadyRouted;

public class ForwardRoutingFilter implements GlobalFilter, Ordered {

    private static final Log log = LogFactory.getLog(ForwardRoutingFilter.class);

    private final ObjectProvider<DispatcherHandler> dispatcherHandlerProvider;

    // do not use this dispatcherHandler directly, use getDispatcherHandler() instead.
    private volatile DispatcherHandler dispatcherHandler;

    public ForwardRoutingFilter(ObjectProvider<DispatcherHandler> dispatcherHandlerProvider) {
        this.dispatcherHandlerProvider = dispatcherHandlerProvider;
    }

    private DispatcherHandler getDispatcherHandler() {
        if (dispatcherHandler == null) {
            dispatcherHandler = dispatcherHandlerProvider.getIfAvailable();
        }

        return dispatcherHandler;
    }

    @Override
    public int getOrder() {
        return Ordered.LOWEST_PRECEDENCE;
    }

    @Override
    public Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) {
        URI requestUrl = exchange.getRequiredAttribute(GATEWAY_REQUEST_URL_ATTR);

        String scheme = requestUrl.getScheme();
        if (isAlreadyRouted(exchange) || !"forward".equals(scheme)) {
            return chain.filter(exchange);
        }
        setAlreadyRouted(exchange);

        // TODO: translate url?

        if (log.isTraceEnabled()) {
            log.trace("Forwarding to URI: " + requestUrl);
        }

        return this.getDispatcherHandler().handle(exchange);
    }

}