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 * 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.base64;
17
18 import org.jboss.netty.buffer.ChannelBuffer;
19 import org.jboss.netty.buffer.ChannelBuffers;
20 import org.jboss.netty.channel.Channel;
21 import org.jboss.netty.channel.ChannelHandler.Sharable;
22 import org.jboss.netty.channel.ChannelHandlerContext;
23 import org.jboss.netty.channel.ChannelPipeline;
24 import org.jboss.netty.handler.codec.frame.DelimiterBasedFrameDecoder;
25 import org.jboss.netty.handler.codec.frame.Delimiters;
26 import org.jboss.netty.handler.codec.frame.FrameDecoder;
27 import org.jboss.netty.handler.codec.oneone.OneToOneDecoder;
28 import org.jboss.netty.util.CharsetUtil;
29
30 /**
31 * Decodes a Base64-encoded {@link ChannelBuffer} or US-ASCII {@link String}
32 * into a {@link ChannelBuffer}. Please note that this decoder must be used
33 * with a proper {@link FrameDecoder} such as {@link DelimiterBasedFrameDecoder}
34 * if you are using a stream-based transport such as TCP/IP. A typical decoder
35 * setup for TCP/IP would be:
36 * <pre>
37 * {@link ChannelPipeline} pipeline = ...;
38 *
39 * // Decoders
40 * pipeline.addLast("frameDecoder", new {@link DelimiterBasedFrameDecoder}(80, {@link Delimiters#nulDelimiter()}));
41 * pipeline.addLast("base64Decoder", new {@link Base64Decoder}());
42 *
43 * // Encoder
44 * pipeline.addLast("base64Encoder", new {@link Base64Encoder}());
45 * </pre>
46 * @apiviz.landmark
47 * @apiviz.uses org.jboss.netty.handler.codec.base64.Base64
48 */
49 @Sharable
50 public class Base64Decoder extends OneToOneDecoder {
51
52 private final Base64Dialect dialect;
53
54 public Base64Decoder() {
55 this(Base64Dialect.STANDARD);
56 }
57
58 public Base64Decoder(Base64Dialect dialect) {
59 if (dialect == null) {
60 throw new NullPointerException("dialect");
61 }
62 this.dialect = dialect;
63 }
64
65 @Override
66 protected Object decode(ChannelHandlerContext ctx, Channel channel, Object msg)
67 throws Exception {
68 if (msg instanceof String) {
69 msg = ChannelBuffers.copiedBuffer((String) msg, CharsetUtil.US_ASCII);
70 } else if (!(msg instanceof ChannelBuffer)) {
71 return msg;
72 }
73
74 ChannelBuffer src = (ChannelBuffer) msg;
75 return Base64.decode(
76 src, src.readerIndex(), src.readableBytes(), dialect);
77 }
78
79 }