Java tutorial
/* * Licensed to Elasticsearch under one or more contributor * license agreements. See the NOTICE file distributed with * this work for additional information regarding copyright * ownership. Elasticsearch licenses this file to you 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.elasticsearch.http.netty4; import io.netty.bootstrap.Bootstrap; import io.netty.buffer.ByteBuf; import io.netty.buffer.Unpooled; import io.netty.channel.ChannelFuture; import io.netty.channel.ChannelHandlerContext; import io.netty.channel.ChannelInitializer; import io.netty.channel.SimpleChannelInboundHandler; 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.DefaultFullHttpRequest; import io.netty.handler.codec.http.FullHttpRequest; import io.netty.handler.codec.http.FullHttpResponse; import io.netty.handler.codec.http.HttpHeaderNames; import io.netty.handler.codec.http.HttpMethod; import io.netty.handler.codec.http.HttpObject; import io.netty.handler.codec.http.HttpObjectAggregator; import io.netty.handler.codec.http.HttpRequest; import io.netty.handler.codec.http.HttpRequestEncoder; import io.netty.handler.codec.http.HttpResponse; import io.netty.handler.codec.http.HttpResponseDecoder; import io.netty.handler.codec.http.HttpVersion; import org.elasticsearch.common.collect.Tuple; import org.elasticsearch.common.unit.ByteSizeUnit; import org.elasticsearch.common.unit.ByteSizeValue; import java.io.Closeable; import java.net.SocketAddress; import java.nio.charset.StandardCharsets; import java.util.ArrayList; import java.util.Collection; import java.util.Collections; import java.util.List; import java.util.concurrent.CountDownLatch; import java.util.concurrent.TimeUnit; import static io.netty.handler.codec.http.HttpHeaderNames.HOST; import static io.netty.handler.codec.http.HttpVersion.HTTP_1_1; /** * Tiny helper to send http requests over netty. */ class Netty4HttpClient implements Closeable { static Collection<String> returnHttpResponseBodies(Collection<FullHttpResponse> responses) { List<String> list = new ArrayList<>(responses.size()); for (FullHttpResponse response : responses) { list.add(response.content().toString(StandardCharsets.UTF_8)); } return list; } static Collection<String> returnOpaqueIds(Collection<FullHttpResponse> responses) { List<String> list = new ArrayList<>(responses.size()); for (HttpResponse response : responses) { list.add(response.headers().get("X-Opaque-Id")); } return list; } private final Bootstrap clientBootstrap; Netty4HttpClient() { clientBootstrap = new Bootstrap().channel(NioSocketChannel.class).group(new NioEventLoopGroup()); } public Collection<FullHttpResponse> get(SocketAddress remoteAddress, String... uris) throws InterruptedException { Collection<HttpRequest> requests = new ArrayList<>(uris.length); for (int i = 0; i < uris.length; i++) { final HttpRequest httpRequest = new DefaultFullHttpRequest(HTTP_1_1, HttpMethod.GET, uris[i]); httpRequest.headers().add(HOST, "localhost"); httpRequest.headers().add("X-Opaque-ID", String.valueOf(i)); requests.add(httpRequest); } return sendRequests(remoteAddress, requests); } @SafeVarargs // Safe not because it doesn't do anything with the type parameters but because it won't leak them into other methods. public final Collection<FullHttpResponse> post(SocketAddress remoteAddress, Tuple<String, CharSequence>... urisAndBodies) throws InterruptedException { return processRequestsWithBody(HttpMethod.POST, remoteAddress, urisAndBodies); } public final FullHttpResponse post(SocketAddress remoteAddress, FullHttpRequest httpRequest) throws InterruptedException { Collection<FullHttpResponse> responses = sendRequests(remoteAddress, Collections.singleton(httpRequest)); assert responses.size() == 1 : "expected 1 and only 1 http response"; return responses.iterator().next(); } @SafeVarargs // Safe not because it doesn't do anything with the type parameters but because it won't leak them into other methods. public final Collection<FullHttpResponse> put(SocketAddress remoteAddress, Tuple<String, CharSequence>... urisAndBodies) throws InterruptedException { return processRequestsWithBody(HttpMethod.PUT, remoteAddress, urisAndBodies); } private Collection<FullHttpResponse> processRequestsWithBody(HttpMethod method, SocketAddress remoteAddress, Tuple<String, CharSequence>... urisAndBodies) throws InterruptedException { Collection<HttpRequest> requests = new ArrayList<>(urisAndBodies.length); for (Tuple<String, CharSequence> uriAndBody : urisAndBodies) { ByteBuf content = Unpooled.copiedBuffer(uriAndBody.v2(), StandardCharsets.UTF_8); HttpRequest request = new DefaultFullHttpRequest(HttpVersion.HTTP_1_1, method, uriAndBody.v1(), content); request.headers().add(HttpHeaderNames.HOST, "localhost"); request.headers().add(HttpHeaderNames.CONTENT_LENGTH, content.readableBytes()); requests.add(request); } return sendRequests(remoteAddress, requests); } private synchronized Collection<FullHttpResponse> sendRequests(final SocketAddress remoteAddress, final Collection<HttpRequest> requests) throws InterruptedException { final CountDownLatch latch = new CountDownLatch(requests.size()); final Collection<FullHttpResponse> content = Collections.synchronizedList(new ArrayList<>(requests.size())); clientBootstrap.handler(new CountDownLatchHandler(latch, content)); ChannelFuture channelFuture = null; try { channelFuture = clientBootstrap.connect(remoteAddress); channelFuture.sync(); for (HttpRequest request : requests) { channelFuture.channel().writeAndFlush(request); } latch.await(10, TimeUnit.SECONDS); } finally { if (channelFuture != null) { channelFuture.channel().close().sync(); } } return content; } @Override public void close() { clientBootstrap.config().group().shutdownGracefully().awaitUninterruptibly(); } /** * helper factory which adds returned data to a list and uses a count down latch to decide when done */ private static class CountDownLatchHandler extends ChannelInitializer<SocketChannel> { private final CountDownLatch latch; private final Collection<FullHttpResponse> content; CountDownLatchHandler(final CountDownLatch latch, final Collection<FullHttpResponse> content) { this.latch = latch; this.content = content; } @Override protected void initChannel(SocketChannel ch) throws Exception { final int maxContentLength = new ByteSizeValue(100, ByteSizeUnit.MB).bytesAsInt(); ch.pipeline().addLast(new HttpResponseDecoder()); ch.pipeline().addLast(new HttpRequestEncoder()); ch.pipeline().addLast(new HttpObjectAggregator(maxContentLength)); ch.pipeline().addLast(new SimpleChannelInboundHandler<HttpObject>() { @Override protected void channelRead0(ChannelHandlerContext ctx, HttpObject msg) throws Exception { final FullHttpResponse response = (FullHttpResponse) msg; content.add(response.copy()); latch.countDown(); } @Override public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception { super.exceptionCaught(ctx, cause); latch.countDown(); } }); } } }