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 io.netty.handler.codec.base64;
17
18 import io.netty.buffer.ByteBuf;
19 import io.netty.channel.ChannelHandler.Sharable;
20 import io.netty.channel.ChannelHandlerContext;
21 import io.netty.channel.ChannelPipeline;
22 import io.netty.handler.codec.ByteToMessageDecoder;
23 import io.netty.handler.codec.DelimiterBasedFrameDecoder;
24 import io.netty.handler.codec.Delimiters;
25 import io.netty.handler.codec.MessageToMessageDecoder;
26
27 import java.util.List;
28
29 /**
30 * Decodes a Base64-encoded {@link ByteBuf} or US-ASCII {@link String}
31 * into a {@link ByteBuf}. Please note that this decoder must be used
32 * with a proper {@link ByteToMessageDecoder} such as {@link DelimiterBasedFrameDecoder}
33 * if you are using a stream-based transport such as TCP/IP. A typical decoder
34 * setup for TCP/IP would be:
35 * <pre>
36 * {@link ChannelPipeline} pipeline = ...;
37 *
38 * // Decoders
39 * pipeline.addLast("frameDecoder", new {@link DelimiterBasedFrameDecoder}(80, {@link Delimiters#nulDelimiter()}));
40 * pipeline.addLast("base64Decoder", new {@link Base64Decoder}());
41 *
42 * // Encoder
43 * pipeline.addLast("base64Encoder", new {@link Base64Encoder}());
44 * </pre>
45 */
46 @Sharable
47 public class Base64Decoder extends MessageToMessageDecoder<ByteBuf> {
48
49 private final Base64Dialect dialect;
50
51 public Base64Decoder() {
52 this(Base64Dialect.STANDARD);
53 }
54
55 public Base64Decoder(Base64Dialect dialect) {
56 if (dialect == null) {
57 throw new NullPointerException("dialect");
58 }
59 this.dialect = dialect;
60 }
61
62 @Override
63 protected void decode(ChannelHandlerContext ctx, ByteBuf msg, List<Object> out) throws Exception {
64 out.add(Base64.decode(msg, msg.readerIndex(), msg.readableBytes(), dialect));
65 }
66 }