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.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 import io.netty.util.internal.ObjectUtil;
27
28 import java.util.List;
29
30 /**
31 * Decodes a Base64-encoded {@link ByteBuf} or US-ASCII {@link String}
32 * into a {@link ByteBuf}. Please note that this decoder must be used
33 * with a proper {@link ByteToMessageDecoder} 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 */
47 @Sharable
48 public class Base64Decoder extends MessageToMessageDecoder<ByteBuf> {
49
50 private final Base64Dialect dialect;
51
52 public Base64Decoder() {
53 this(Base64Dialect.STANDARD);
54 }
55
56 public Base64Decoder(Base64Dialect dialect) {
57 this.dialect = ObjectUtil.checkNotNull(dialect, "dialect");
58 }
59
60 @Override
61 protected void decode(ChannelHandlerContext ctx, ByteBuf msg, List<Object> out) throws Exception {
62 out.add(Base64.decode(msg, msg.readerIndex(), msg.readableBytes(), dialect));
63 }
64 }