Java tutorial
/* * (C) Copyright 2015-2016 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. * * Contributors: * ohun@live.cn () */ package com.mpush.netty.http; import com.mpush.api.service.BaseService; import com.mpush.api.service.Listener; import com.mpush.tools.config.CC; import com.mpush.tools.thread.NamedThreadFactory; import com.mpush.tools.thread.ThreadNames; import io.netty.bootstrap.Bootstrap; import io.netty.buffer.PooledByteBufAllocator; import io.netty.channel.*; import io.netty.channel.nio.NioEventLoopGroup; import io.netty.channel.socket.SocketChannel; import io.netty.channel.socket.nio.NioSocketChannel; import io.netty.handler.codec.http.HttpObjectAggregator; import io.netty.handler.codec.http.HttpRequestEncoder; import io.netty.handler.codec.http.HttpResponseDecoder; import io.netty.util.AttributeKey; import io.netty.util.HashedWheelTimer; import io.netty.util.Timer; import io.netty.util.concurrent.DefaultThreadFactory; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import java.net.URI; import java.util.concurrent.TimeUnit; import static com.mpush.tools.config.CC.mp.thread.pool.http_work; import static com.mpush.tools.thread.ThreadNames.T_HTTP_TIMER; import static io.netty.handler.codec.http.HttpHeaderNames.CONNECTION; import static io.netty.handler.codec.http.HttpHeaderNames.HOST; import static io.netty.handler.codec.http.HttpHeaderValues.KEEP_ALIVE; /** * NettyBootstrap??channel * Client????Handler@ChannelHandler.Sharable * ???clienthandler * <p> * Created by ohun on 2016/2/15. * * @author ohun@live.cn */ public class NettyHttpClient extends BaseService implements HttpClient { private static HttpClient I; private static final Logger LOGGER = LoggerFactory.getLogger(NettyHttpClient.class); private static final int maxContentLength = (int) CC.mp.http.max_content_length; /*package*/ final AttributeKey<RequestContext> requestKey = AttributeKey.newInstance("request"); /*package*/ final HttpConnectionPool pool = new HttpConnectionPool(); private Bootstrap b; private EventLoopGroup workerGroup; private Timer timer; public static HttpClient I() { if (I == null) { synchronized (NettyHttpClient.class) { if (I == null) { I = new NettyHttpClient(); } } } return I; } @Override public void request(RequestContext context) throws Exception { URI uri = new URI(context.request.uri()); String host = context.host = uri.getHost(); int port = uri.getPort() == -1 ? 80 : uri.getPort(); //1. context.request.headers().set(HOST, host);//?host context.request.headers().set(CONNECTION, KEEP_ALIVE);//? //2. timer.newTimeout(context, context.readTimeout, TimeUnit.MILLISECONDS); //3.????? Channel channel = pool.tryAcquire(host); if (channel == null) { final long startCreate = System.currentTimeMillis(); LOGGER.debug("create new channel, host={}", host); ChannelFuture f = b.connect(host, port); f.addListener((ChannelFutureListener) future -> { LOGGER.debug("create new channel cost={}", (System.currentTimeMillis() - startCreate)); if (future.isSuccess()) {//3.1.http server writeRequest(future.channel(), context); } else {//3.2 context.tryDone(); context.onFailure(504, "Gateway Timeout"); LOGGER.warn("create new channel failure, request={}", context); } }); } else { //3.1.http server writeRequest(channel, context); } } private void writeRequest(Channel channel, RequestContext context) { channel.attr(requestKey).set(context); pool.attachHost(context.host, channel); channel.writeAndFlush(context.request).addListener((ChannelFutureListener) future -> { if (!future.isSuccess()) { RequestContext info = future.channel().attr(requestKey).getAndSet(null); info.tryDone(); info.onFailure(503, "Service Unavailable"); LOGGER.debug("request failure request={}", info); pool.tryRelease(future.channel()); } }); } @Override protected void doStart(Listener listener) throws Throwable { workerGroup = new NioEventLoopGroup(http_work, new DefaultThreadFactory(ThreadNames.T_HTTP_CLIENT)); b = new Bootstrap(); b.group(workerGroup); b.channel(NioSocketChannel.class); b.option(ChannelOption.SO_KEEPALIVE, true); b.option(ChannelOption.TCP_NODELAY, true); b.option(ChannelOption.SO_REUSEADDR, true); b.option(ChannelOption.CONNECT_TIMEOUT_MILLIS, 4000); b.option(ChannelOption.ALLOCATOR, PooledByteBufAllocator.DEFAULT); b.handler(new ChannelInitializer<SocketChannel>() { @Override public void initChannel(SocketChannel ch) throws Exception { ch.pipeline().addLast("decoder", new HttpResponseDecoder()); ch.pipeline().addLast("aggregator", new HttpObjectAggregator(maxContentLength)); ch.pipeline().addLast("encoder", new HttpRequestEncoder()); ch.pipeline().addLast("handler", new HttpClientHandler(NettyHttpClient.this)); } }); timer = new HashedWheelTimer(new NamedThreadFactory(T_HTTP_TIMER), 1, TimeUnit.SECONDS, 64); listener.onSuccess(); } @Override protected void doStop(Listener listener) throws Throwable { pool.close(); workerGroup.shutdownGracefully(); timer.stop(); listener.onSuccess(); } }