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

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Here is the source code for org.springframework.cloud.gateway.filter.NettyWriteResponseFilter.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.util.List;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import reactor.core.publisher.Flux;
import reactor.core.publisher.Mono;
import reactor.netty.Connection;

import org.springframework.core.Ordered;
import org.springframework.core.io.buffer.NettyDataBuffer;
import org.springframework.core.io.buffer.NettyDataBufferFactory;
import org.springframework.http.MediaType;
import org.springframework.http.server.reactive.ServerHttpResponse;
import org.springframework.lang.Nullable;
import org.springframework.web.server.ServerWebExchange;

import static org.springframework.cloud.gateway.support.ServerWebExchangeUtils.CLIENT_RESPONSE_CONN_ATTR;

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

    /**
     * Order for write response filter.
     */
    public static final int WRITE_RESPONSE_FILTER_ORDER = -1;

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

    private final List<MediaType> streamingMediaTypes;

    public NettyWriteResponseFilter(List<MediaType> streamingMediaTypes) {
        this.streamingMediaTypes = streamingMediaTypes;
    }

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

    @Override
    public Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) {
        // NOTICE: nothing in "pre" filter stage as CLIENT_RESPONSE_CONN_ATTR is not added
        // until the NettyRoutingFilter is run
        return chain.filter(exchange).then(Mono.defer(() -> {
            Connection connection = exchange.getAttribute(CLIENT_RESPONSE_CONN_ATTR);

            if (connection == null) {
                return Mono.empty();
            }
            log.trace("NettyWriteResponseFilter start");
            ServerHttpResponse response = exchange.getResponse();

            NettyDataBufferFactory factory = (NettyDataBufferFactory) response.bufferFactory();
            // TODO: what if it's not netty

            final Flux<NettyDataBuffer> body = connection.inbound().receive().retain() // TODO:
                    // needed?
                    .map(factory::wrap);

            MediaType contentType = null;
            try {
                contentType = response.getHeaders().getContentType();
            } catch (Exception e) {
                log.trace("invalid media type", e);
            }
            return (isStreamingMediaType(contentType) ? response.writeAndFlushWith(body.map(Flux::just))
                    : response.writeWith(body));
        }));
    }

    // TODO: use framework if possible
    // TODO: port to WebClientWriteResponseFilter
    private boolean isStreamingMediaType(@Nullable MediaType contentType) {
        return (contentType != null && this.streamingMediaTypes.stream().anyMatch(contentType::isCompatibleWith));
    }

}