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.netty.handler.codec.http;
17
18 import io.netty.buffer.ByteBuf;
19 import io.netty.buffer.ByteBufUtil;
20
21 import static io.netty.handler.codec.http.HttpConstants.*;
22
23 /**
24 * Encodes an {@link HttpResponse} or an {@link HttpContent} into
25 * a {@link ByteBuf}.
26 */
27 public class HttpResponseEncoder extends HttpObjectEncoder<HttpResponse> {
28
29 @Override
30 public boolean acceptOutboundMessage(Object msg) throws Exception {
31 // JDK type checks vs non-implemented interfaces costs O(N), where
32 // N is the number of interfaces already implemented by the concrete type that's being tested.
33 // !(msg instanceof HttpRequest) is supposed to always be true (and meaning that msg isn't a HttpRequest),
34 // but sadly was part of the original behaviour of this method and cannot be removed.
35 // We place here exact checks vs DefaultHttpResponse and DefaultFullHttpResponse because bad users can
36 // extends such types and make them to implement HttpRequest (non-sense, but still possible).
37 final Class<?> msgClass = msg.getClass();
38 if (msgClass == DefaultFullHttpResponse.class || msgClass == DefaultHttpResponse.class) {
39 return true;
40 }
41 return super.acceptOutboundMessage(msg) && !(msg instanceof HttpRequest);
42 }
43
44 @Override
45 protected void encodeInitialLine(ByteBuf buf, HttpResponse response) throws Exception {
46 response.protocolVersion().encode(buf);
47 buf.writeByte(SP);
48 response.status().encode(buf);
49 ByteBufUtil.writeShortBE(buf, CRLF_SHORT);
50 }
51
52 @Override
53 protected void sanitizeHeadersBeforeEncode(HttpResponse msg, boolean isAlwaysEmpty) {
54 if (isAlwaysEmpty) {
55 HttpResponseStatus status = msg.status();
56 if (status.codeClass() == HttpStatusClass.INFORMATIONAL ||
57 status.code() == HttpResponseStatus.NO_CONTENT.code()) {
58
59 // Stripping Content-Length:
60 // See https://tools.ietf.org/html/rfc7230#section-3.3.2
61 msg.headers().remove(HttpHeaderNames.CONTENT_LENGTH);
62
63 // Stripping Transfer-Encoding:
64 // See https://tools.ietf.org/html/rfc7230#section-3.3.1
65 msg.headers().remove(HttpHeaderNames.TRANSFER_ENCODING);
66 } else if (status.code() == HttpResponseStatus.RESET_CONTENT.code()) {
67
68 // Stripping Transfer-Encoding:
69 msg.headers().remove(HttpHeaderNames.TRANSFER_ENCODING);
70
71 // Set Content-Length: 0
72 // https://httpstatuses.com/205
73 msg.headers().setInt(HttpHeaderNames.CONTENT_LENGTH, 0);
74 }
75 }
76 }
77
78 @Override
79 protected boolean isContentAlwaysEmpty(HttpResponse msg) {
80 // Correctly handle special cases as stated in:
81 // https://tools.ietf.org/html/rfc7230#section-3.3.3
82 HttpResponseStatus status = msg.status();
83
84 if (status.codeClass() == HttpStatusClass.INFORMATIONAL) {
85
86 if (status.code() == HttpResponseStatus.SWITCHING_PROTOCOLS.code()) {
87 // We need special handling for WebSockets version 00 as it will include an body.
88 // Fortunally this version should not really be used in the wild very often.
89 // See https://tools.ietf.org/html/draft-ietf-hybi-thewebsocketprotocol-00#section-1.2
90 return msg.headers().contains(HttpHeaderNames.SEC_WEBSOCKET_VERSION);
91 }
92 return true;
93 }
94 return status.code() == HttpResponseStatus.NO_CONTENT.code() ||
95 status.code() == HttpResponseStatus.NOT_MODIFIED.code() ||
96 status.code() == HttpResponseStatus.RESET_CONTENT.code();
97 }
98 }