Java tutorial
/* * Copyright 2015 The Netty Project * * The Netty Project 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 com.flysoloing.learning.network.netty.http2.tiles; import io.netty.buffer.ByteBuf; import io.netty.channel.ChannelHandlerContext; import io.netty.channel.SimpleChannelInboundHandler; import io.netty.handler.codec.http.DefaultFullHttpResponse; import io.netty.handler.codec.http.FullHttpRequest; import io.netty.handler.codec.http.FullHttpResponse; import io.netty.handler.codec.http.QueryStringDecoder; import io.netty.handler.codec.http2.HttpConversionUtil; import io.netty.handler.codec.http2.InboundHttp2ToHttpAdapter; import java.util.concurrent.TimeUnit; import static io.netty.buffer.Unpooled.EMPTY_BUFFER; import static com.flysoloing.learning.network.netty.http2.Http2ExampleUtil.firstValue; import static com.flysoloing.learning.network.netty.http2.Http2ExampleUtil.toInt; import static io.netty.handler.codec.http.HttpHeaderNames.CONTENT_TYPE; import static io.netty.handler.codec.http.HttpResponseStatus.BAD_REQUEST; import static io.netty.handler.codec.http.HttpResponseStatus.OK; import static io.netty.handler.codec.http.HttpUtil.setContentLength; import static io.netty.handler.codec.http.HttpVersion.HTTP_1_1; import static java.lang.Integer.parseInt; /** * Handles all the requests for data. It receives a {@link FullHttpRequest}, * which has been converted by a {@link InboundHttp2ToHttpAdapter} before it * arrived here. For further details, check {@link Http2OrHttpHandler} where the * pipeline is setup. */ public class Http2RequestHandler extends SimpleChannelInboundHandler<FullHttpRequest> { private static final String LATENCY_FIELD_NAME = "latency"; private static final int MIN_LATENCY = 0; private static final int MAX_LATENCY = 1000; private static final String IMAGE_COORDINATE_Y = "y"; private static final String IMAGE_COORDINATE_X = "x"; @Override protected void channelRead0(ChannelHandlerContext ctx, FullHttpRequest request) throws Exception { QueryStringDecoder queryString = new QueryStringDecoder(request.uri()); String streamId = streamId(request); int latency = toInt(firstValue(queryString, LATENCY_FIELD_NAME), 0); if (latency < MIN_LATENCY || latency > MAX_LATENCY) { sendBadRequest(ctx, streamId); return; } String x = firstValue(queryString, IMAGE_COORDINATE_X); String y = firstValue(queryString, IMAGE_COORDINATE_Y); if (x == null || y == null) { handlePage(ctx, streamId, latency, request); } else { handleImage(x, y, ctx, streamId, latency, request); } } private void sendBadRequest(ChannelHandlerContext ctx, String streamId) { FullHttpResponse response = new DefaultFullHttpResponse(HTTP_1_1, BAD_REQUEST, EMPTY_BUFFER); streamId(response, streamId); ctx.writeAndFlush(response); } private void handleImage(String x, String y, ChannelHandlerContext ctx, String streamId, int latency, FullHttpRequest request) { ByteBuf image = ImageCache.INSTANCE.image(parseInt(x), parseInt(y)); FullHttpResponse response = new DefaultFullHttpResponse(HTTP_1_1, OK, image.duplicate()); response.headers().set(CONTENT_TYPE, "image/jpeg"); sendResponse(ctx, streamId, latency, response, request); } private void handlePage(ChannelHandlerContext ctx, String streamId, int latency, FullHttpRequest request) { byte[] body = Html.body(latency); ByteBuf content = ctx.alloc().buffer(Html.HEADER.length + body.length + Html.FOOTER.length); content.writeBytes(Html.HEADER); content.writeBytes(body); content.writeBytes(Html.FOOTER); FullHttpResponse response = new DefaultFullHttpResponse(HTTP_1_1, OK, content); response.headers().set(CONTENT_TYPE, "text/html; charset=UTF-8"); sendResponse(ctx, streamId, latency, response, request); } protected void sendResponse(final ChannelHandlerContext ctx, String streamId, int latency, final FullHttpResponse response, final FullHttpRequest request) { setContentLength(response, response.content().readableBytes()); streamId(response, streamId); ctx.executor().schedule(new Runnable() { public void run() { ctx.writeAndFlush(response); } }, latency, TimeUnit.MILLISECONDS); } private static String streamId(FullHttpRequest request) { return request.headers().get(HttpConversionUtil.ExtensionHeaderNames.STREAM_ID.text()); } private static void streamId(FullHttpResponse response, String streamId) { response.headers().set(HttpConversionUtil.ExtensionHeaderNames.STREAM_ID.text(), streamId); } @Override public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception { cause.printStackTrace(); ctx.close(); } }