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1   /*
2    * Copyright 2016 The Netty Project
3    *
4    * The Netty Project licenses this file to you under the Apache License, version 2.0 (the
5    * "License"); you may not use this file except in compliance with the License. You may obtain a
6    * 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 distributed under the License
11   * is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
12   * or implied. See the License for the specific language governing permissions and limitations under
13   * the License.
14   */
15  package io.netty.example.http2.helloworld.multiplex.server;
16  
17  import io.netty.channel.ChannelHandlerContext;
18  import io.netty.example.http2.helloworld.server.HelloWorldHttp1Handler;
19  import io.netty.handler.codec.http.HttpObjectAggregator;
20  import io.netty.handler.codec.http.HttpServerCodec;
21  import io.netty.handler.codec.http2.Http2MultiplexCodecBuilder;
22  import io.netty.handler.ssl.ApplicationProtocolNames;
23  import io.netty.handler.ssl.ApplicationProtocolNegotiationHandler;
24  
25  /**
26   * Negotiates with the browser if HTTP2 or HTTP is going to be used. Once decided, the Netty
27   * pipeline is setup with the correct handlers for the selected protocol.
28   */
29  public class Http2OrHttpHandler extends ApplicationProtocolNegotiationHandler {
30  
31      private static final int MAX_CONTENT_LENGTH = 1024 * 100;
32  
33      protected Http2OrHttpHandler() {
34          super(ApplicationProtocolNames.HTTP_1_1);
35      }
36  
37      @Override
38      protected void configurePipeline(ChannelHandlerContext ctx, String protocol) throws Exception {
39          if (ApplicationProtocolNames.HTTP_2.equals(protocol)) {
40              ctx.pipeline().addLast(Http2MultiplexCodecBuilder.forServer(new HelloWorldHttp2Handler()).build());
41              return;
42          }
43  
44          if (ApplicationProtocolNames.HTTP_1_1.equals(protocol)) {
45              ctx.pipeline().addLast(new HttpServerCodec(),
46                                     new HttpObjectAggregator(MAX_CONTENT_LENGTH),
47                                     new HelloWorldHttp1Handler("ALPN Negotiation"));
48              return;
49          }
50  
51          throw new IllegalStateException("unknown protocol: " + protocol);
52      }
53  }