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1   /*
2    * Copyright 2012 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    *   https://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  package io.netty5.handler.codec.http;
17  
18  import io.netty5.buffer.api.Buffer;
19  
20  import static io.netty5.handler.codec.http.HttpConstants.SP;
21  
22  /**
23   * Encodes an {@link HttpResponse} or an {@link HttpContent} into a {@link Buffer}.
24   */
25  public class HttpResponseEncoder extends HttpObjectEncoder<HttpResponse> {
26  
27      @Override
28      public boolean acceptOutboundMessage(Object msg) throws Exception {
29          return super.acceptOutboundMessage(msg) && !(msg instanceof HttpRequest);
30      }
31  
32      @Override
33      protected void encodeInitialLine(Buffer buf, HttpResponse response) throws Exception {
34          response.protocolVersion().encode(buf);
35          buf.writeByte(SP);
36          response.status().encode(buf);
37          buf.writeShort(CRLF_SHORT);
38      }
39  
40      @Override
41      protected void sanitizeHeadersBeforeEncode(HttpResponse msg, boolean isAlwaysEmpty) {
42          if (isAlwaysEmpty) {
43              HttpResponseStatus status = msg.status();
44              if (status.codeClass() == HttpStatusClass.INFORMATIONAL ||
45                      status.code() == HttpResponseStatus.NO_CONTENT.code()) {
46  
47                  // Stripping Content-Length:
48                  // See https://tools.ietf.org/html/rfc7230#section-3.3.2
49                  msg.headers().remove(HttpHeaderNames.CONTENT_LENGTH);
50  
51                  // Stripping Transfer-Encoding:
52                  // See https://tools.ietf.org/html/rfc7230#section-3.3.1
53                  msg.headers().remove(HttpHeaderNames.TRANSFER_ENCODING);
54              } else if (status.code() == HttpResponseStatus.RESET_CONTENT.code()) {
55  
56                  // Stripping Transfer-Encoding:
57                  msg.headers().remove(HttpHeaderNames.TRANSFER_ENCODING);
58  
59                  // Set Content-Length: 0
60                  // https://httpstatuses.com/205
61                  msg.headers().setInt(HttpHeaderNames.CONTENT_LENGTH, 0);
62              }
63          }
64      }
65  
66      @Override
67      protected boolean isContentAlwaysEmpty(HttpResponse msg) {
68          // Correctly handle special cases as stated in:
69          // https://tools.ietf.org/html/rfc7230#section-3.3.3
70          HttpResponseStatus status = msg.status();
71  
72          if (status.codeClass() == HttpStatusClass.INFORMATIONAL) {
73  
74              if (status.code() == HttpResponseStatus.SWITCHING_PROTOCOLS.code()) {
75                  // We need special handling for WebSockets version 00 as it will include a body.
76                  // Fortunately, this version should not really be used in the wild very often.
77                  // See https://tools.ietf.org/html/draft-ietf-hybi-thewebsocketprotocol-00#section-1.2
78                  return msg.headers().contains(HttpHeaderNames.SEC_WEBSOCKET_VERSION);
79              }
80              return true;
81          }
82          return status.code() == HttpResponseStatus.NO_CONTENT.code() ||
83                  status.code() == HttpResponseStatus.NOT_MODIFIED.code() ||
84                  status.code() == HttpResponseStatus.RESET_CONTENT.code();
85      }
86  }