781a85520c
Motivation: Adding an example that showcases Netty’s HTTP/2 codec and that is slightly more complex than the existing hello-world example. It is based on the Gopher tiles example available here: https://http2.golang.org/gophertiles?latency=0 Modifications: Moved current http2 example to http2/helloworld. Added http2 tiles example under http2/tiles. Result: A Netty tiles example is available.
123 lines
5.3 KiB
Java
123 lines
5.3 KiB
Java
/*
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* Copyright 2015 The Netty Project
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*
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* The Netty Project licenses this file to you under the Apache License,
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* version 2.0 (the "License"); you may not use this file except in compliance
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* with the License. You may obtain a copy of the License at:
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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* License for the specific language governing permissions and limitations
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* under the License.
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*/
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package io.netty.example.http2.tiles;
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import static io.netty.buffer.Unpooled.EMPTY_BUFFER;
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import static io.netty.example.http2.Http2ExampleUtil.firstValue;
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import static io.netty.example.http2.Http2ExampleUtil.toInt;
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import static io.netty.handler.codec.http.HttpHeaderNames.CONTENT_TYPE;
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import static io.netty.handler.codec.http.HttpHeaderUtil.setContentLength;
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import static io.netty.handler.codec.http.HttpResponseStatus.BAD_REQUEST;
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import static io.netty.handler.codec.http.HttpResponseStatus.OK;
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import static io.netty.handler.codec.http.HttpVersion.HTTP_1_1;
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import static java.lang.Integer.valueOf;
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import io.netty.buffer.ByteBuf;
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import io.netty.channel.ChannelHandlerContext;
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import io.netty.channel.SimpleChannelInboundHandler;
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import io.netty.handler.codec.http.DefaultFullHttpResponse;
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import io.netty.handler.codec.http.FullHttpRequest;
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import io.netty.handler.codec.http.FullHttpResponse;
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import io.netty.handler.codec.http.QueryStringDecoder;
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import io.netty.handler.codec.http2.HttpUtil;
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import io.netty.handler.codec.http2.InboundHttp2ToHttpAdapter;
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import java.util.concurrent.TimeUnit;
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/**
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* Handles all the requests for data. It receives a {@link FullHttpRequest},
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* which has been converted by a {@link InboundHttp2ToHttpAdapter} before it
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* arrived here. For further details, check {@link Http2OrHttpHandler} where the
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* pipeline is setup.
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*/
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public class Http2RequestHandler extends SimpleChannelInboundHandler<FullHttpRequest> {
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private static final String LATENCY_FIELD_NAME = "latency";
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private static final int MIN_LATENCY = 0;
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private static final int MAX_LATENCY = 1000;
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private static final String IMAGE_COORDINATE_Y = "y";
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private static final String IMAGE_COORDINATE_X = "x";
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@Override
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protected void channelRead0(ChannelHandlerContext ctx, FullHttpRequest request) throws Exception {
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QueryStringDecoder queryString = new QueryStringDecoder(request.uri());
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String streamId = streamId(request);
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int latency = toInt(firstValue(queryString, LATENCY_FIELD_NAME), 0);
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if (latency < MIN_LATENCY || latency > MAX_LATENCY) {
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sendBadRequest(ctx, streamId);
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return;
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}
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String x = firstValue(queryString, IMAGE_COORDINATE_X);
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String y = firstValue(queryString, IMAGE_COORDINATE_Y);
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if (x == null || y == null) {
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handlePage(ctx, streamId, latency, request);
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} else {
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handleImage(x, y, ctx, streamId, latency, request);
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}
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}
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private void sendBadRequest(ChannelHandlerContext ctx, String streamId) {
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FullHttpResponse response = new DefaultFullHttpResponse(HTTP_1_1, BAD_REQUEST, EMPTY_BUFFER);
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streamId(response, streamId);
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ctx.writeAndFlush(response);
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}
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private void handleImage(String x, String y, ChannelHandlerContext ctx, String streamId, int latency,
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FullHttpRequest request) {
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ByteBuf image = ImageCache.INSTANCE.image(valueOf(x), valueOf(y));
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FullHttpResponse response = new DefaultFullHttpResponse(HTTP_1_1, OK, image.duplicate());
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response.headers().set(CONTENT_TYPE, "image/jpeg");
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sendResponse(ctx, streamId, latency, response, request);
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}
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private void handlePage(ChannelHandlerContext ctx, String streamId, int latency, FullHttpRequest request) {
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byte[] body = Html.body(latency);
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ByteBuf content = ctx.alloc().buffer(Html.HEADER.length + body.length + Html.FOOTER.length);
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content.writeBytes(Html.HEADER);
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content.writeBytes(body);
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content.writeBytes(Html.FOOTER);
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FullHttpResponse response = new DefaultFullHttpResponse(HTTP_1_1, OK, content);
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response.headers().set(CONTENT_TYPE, "text/html; charset=UTF-8");
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sendResponse(ctx, streamId, latency, response, request);
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}
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protected void sendResponse(final ChannelHandlerContext ctx, String streamId, int latency,
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final FullHttpResponse response, final FullHttpRequest request) {
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setContentLength(response, response.content().readableBytes());
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streamId(response, streamId);
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ctx.executor().schedule(new Runnable() {
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@Override
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public void run() {
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ctx.writeAndFlush(response);
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}
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}, latency, TimeUnit.MILLISECONDS);
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}
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private String streamId(FullHttpRequest request) {
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return request.headers().get(HttpUtil.ExtensionHeaderNames.STREAM_ID.text());
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}
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private void streamId(FullHttpResponse response, String streamId) {
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response.headers().set(HttpUtil.ExtensionHeaderNames.STREAM_ID.text(), streamId);
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}
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@Override
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public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
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cause.printStackTrace();
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ctx.close();
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}
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}
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