1 /*
2 * Copyright 2009 Red Hat, Inc.
3 *
4 * Red Hat licenses this file to you under the Apache License, version 2.0
5 * (the "License"); you may not use this file except in compliance with the
6 * 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 package org.jboss.netty.handler.codec.http;
17
18 import org.jboss.netty.buffer.ChannelBuffer;
19 import org.jboss.netty.handler.codec.compression.ZlibEncoder;
20 import org.jboss.netty.handler.codec.compression.ZlibWrapper;
21 import org.jboss.netty.handler.codec.embedder.EncoderEmbedder;
22
23 /**
24 * Compresses an {@link HttpMessage} and an {@link HttpChunk} in {@code gzip} or
25 * {@code deflate} encoding while respecting the {@code "Accept-Encoding"} header.
26 * If there is no matching encoding, no compression is done. For more
27 * information on how this handler modifies the message, please refer to
28 * {@link HttpContentEncoder}.
29 *
30 * @author <a href="http://www.jboss.org/netty/">The Netty Project</a>
31 * @author <a href="http://gleamynode.net/">Trustin Lee</a>
32 * @version $Rev: 2121 $, $Date: 2010-02-02 09:38:07 +0900 (Tue, 02 Feb 2010) $
33 */
34 public class HttpContentCompressor extends HttpContentEncoder {
35
36 private final int compressionLevel;
37
38 /**
39 * Creates a new handler with the default compression level (<tt>6</tt>).
40 */
41 public HttpContentCompressor() {
42 this(6);
43 }
44
45 /**
46 * Creates a new handler with the specified compression level.
47 *
48 * @param compressionLevel
49 * {@code 1} yields the fastest compression and {@code 9} yields the
50 * best compression. {@code 0} means no compression. The default
51 * compression level is {@code 6}.
52 */
53 public HttpContentCompressor(int compressionLevel) {
54 if (compressionLevel < 0 || compressionLevel > 9) {
55 throw new IllegalArgumentException(
56 "compressionLevel: " + compressionLevel +
57 " (expected: 0-9)");
58 }
59 this.compressionLevel = compressionLevel;
60 }
61
62 @Override
63 protected EncoderEmbedder<ChannelBuffer> newContentEncoder(String acceptEncoding) throws Exception {
64 ZlibWrapper wrapper = determineWrapper(acceptEncoding);
65 if (wrapper == null) {
66 return null;
67 }
68
69 return new EncoderEmbedder<ChannelBuffer>(new ZlibEncoder(wrapper, compressionLevel));
70 }
71
72 @Override
73 protected String getTargetContentEncoding(String acceptEncoding) throws Exception {
74 ZlibWrapper wrapper = determineWrapper(acceptEncoding);
75 if (wrapper == null) {
76 return null;
77 }
78
79 switch (wrapper) {
80 case GZIP:
81 return "gzip";
82 case ZLIB:
83 return "deflate";
84 default:
85 throw new Error();
86 }
87 }
88
89 private ZlibWrapper determineWrapper(String acceptEncoding) {
90 // FIXME: Use the Q value.
91 if (acceptEncoding.indexOf("gzip") >= 0) {
92 return ZlibWrapper.GZIP;
93 }
94 if (acceptEncoding.indexOf("deflate") >= 0) {
95 return ZlibWrapper.ZLIB;
96 }
97 return null;
98 }
99 }