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1   /*
2    * Copyright 2015 The Netty Project
3    *
4    * The Netty Project licenses this file to you under the Apache License,
5    * version 2.0 (the "License"); you may not use this file except in compliance
6    * with the License. You may obtain a copy of the License at:
7    *
8    *   http://www.apache.org/licenses/LICENSE-2.0
9    *
10   * Unless required by applicable law or agreed to in writing, software
11   * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
12   * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
13   * License for the specific language governing permissions and limitations
14   * under the License.
15   */
16  
17  package io.netty.example.http2.tiles;
18  
19  import static io.netty.buffer.Unpooled.EMPTY_BUFFER;
20  import static io.netty.example.http2.Http2ExampleUtil.firstValue;
21  import static io.netty.example.http2.Http2ExampleUtil.toInt;
22  import static io.netty.handler.codec.http.HttpHeaderNames.CONTENT_TYPE;
23  import static io.netty.handler.codec.http.HttpUtil.setContentLength;
24  import static io.netty.handler.codec.http.HttpResponseStatus.BAD_REQUEST;
25  import static io.netty.handler.codec.http.HttpResponseStatus.OK;
26  import static io.netty.handler.codec.http.HttpVersion.HTTP_1_1;
27  import static java.lang.Integer.parseInt;
28  import io.netty.buffer.ByteBuf;
29  import io.netty.channel.ChannelHandlerContext;
30  import io.netty.channel.SimpleChannelInboundHandler;
31  import io.netty.handler.codec.http.DefaultFullHttpResponse;
32  import io.netty.handler.codec.http.FullHttpRequest;
33  import io.netty.handler.codec.http.FullHttpResponse;
34  import io.netty.handler.codec.http.QueryStringDecoder;
35  import io.netty.handler.codec.http2.HttpConversionUtil;
36  import io.netty.handler.codec.http2.InboundHttp2ToHttpAdapter;
37  
38  import java.util.concurrent.TimeUnit;
39  
40  /**
41   * Handles all the requests for data. It receives a {@link FullHttpRequest},
42   * which has been converted by a {@link InboundHttp2ToHttpAdapter} before it
43   * arrived here. For further details, check {@link Http2OrHttpHandler} where the
44   * pipeline is setup.
45   */
46  public class Http2RequestHandler extends SimpleChannelInboundHandler<FullHttpRequest> {
47  
48      private static final String LATENCY_FIELD_NAME = "latency";
49      private static final int MIN_LATENCY = 0;
50      private static final int MAX_LATENCY = 1000;
51      private static final String IMAGE_COORDINATE_Y = "y";
52      private static final String IMAGE_COORDINATE_X = "x";
53  
54      @Override
55      protected void channelRead0(ChannelHandlerContext ctx, FullHttpRequest request) throws Exception {
56          QueryStringDecoder queryString = new QueryStringDecoder(request.uri());
57          String streamId = streamId(request);
58          int latency = toInt(firstValue(queryString, LATENCY_FIELD_NAME), 0);
59          if (latency < MIN_LATENCY || latency > MAX_LATENCY) {
60              sendBadRequest(ctx, streamId);
61              return;
62          }
63          String x = firstValue(queryString, IMAGE_COORDINATE_X);
64          String y = firstValue(queryString, IMAGE_COORDINATE_Y);
65          if (x == null || y == null) {
66              handlePage(ctx, streamId, latency, request);
67          } else {
68              handleImage(x, y, ctx, streamId, latency, request);
69          }
70      }
71  
72      private static void sendBadRequest(ChannelHandlerContext ctx, String streamId) {
73          FullHttpResponse response = new DefaultFullHttpResponse(HTTP_1_1, BAD_REQUEST, EMPTY_BUFFER);
74          streamId(response, streamId);
75          ctx.writeAndFlush(response);
76      }
77  
78      private void handleImage(String x, String y, ChannelHandlerContext ctx, String streamId, int latency,
79              FullHttpRequest request) {
80          ByteBuf image = ImageCache.INSTANCE.image(parseInt(x), parseInt(y));
81          FullHttpResponse response = new DefaultFullHttpResponse(HTTP_1_1, OK, image.duplicate());
82          response.headers().set(CONTENT_TYPE, "image/jpeg");
83          sendResponse(ctx, streamId, latency, response, request);
84      }
85  
86      private void handlePage(ChannelHandlerContext ctx, String streamId, int latency, FullHttpRequest request) {
87          byte[] body = Html.body(latency);
88          ByteBuf content = ctx.alloc().buffer(Html.HEADER.length + body.length + Html.FOOTER.length);
89          content.writeBytes(Html.HEADER);
90          content.writeBytes(body);
91          content.writeBytes(Html.FOOTER);
92          FullHttpResponse response = new DefaultFullHttpResponse(HTTP_1_1, OK, content);
93          response.headers().set(CONTENT_TYPE, "text/html; charset=UTF-8");
94          sendResponse(ctx, streamId, latency, response, request);
95      }
96  
97      protected void sendResponse(final ChannelHandlerContext ctx, String streamId, int latency,
98              final FullHttpResponse response, final FullHttpRequest request) {
99          setContentLength(response, response.content().readableBytes());
100         streamId(response, streamId);
101         ctx.executor().schedule(new Runnable() {
102             @Override
103             public void run() {
104                 ctx.writeAndFlush(response);
105             }
106         }, latency, TimeUnit.MILLISECONDS);
107     }
108 
109     private static String streamId(FullHttpRequest request) {
110         return request.headers().get(HttpConversionUtil.ExtensionHeaderNames.STREAM_ID.text());
111     }
112 
113     private static void streamId(FullHttpResponse response, String streamId) {
114         response.headers().set(HttpConversionUtil.ExtensionHeaderNames.STREAM_ID.text(), streamId);
115     }
116 
117     @Override
118     public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
119         cause.printStackTrace();
120         ctx.close();
121     }
122 }