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hurelhuyag/EnclosedFrameDecoder.java

Created May 25, 2021 08:40
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netty enclosed frame decoder
Raw
EnclosedFrameDecoder.java
import io.netty.buffer.ByteBuf;
import io.netty.buffer.ByteBufUtil;
import io.netty.buffer.Unpooled;
import io.netty.channel.ChannelHandlerContext;
import io.netty.handler.codec.ByteToMessageDecoder;
import java.util.List;
public class EnclosedFrameDecoder extends ByteToMessageDecoder {
private final ByteBuf startFlag, endFlag;
private final int startLength, endLength;
public EnclosedFrameDecoder(byte[] startFlag, byte[] endFlag) {
this(Unpooled.wrappedBuffer(startFlag), Unpooled.wrappedBuffer(endFlag));
}
public EnclosedFrameDecoder(ByteBuf startFlag, ByteBuf endFlag) {
this.startFlag = startFlag;
this.endFlag = endFlag;
this.startLength = startFlag.readableBytes();
this.endLength = endFlag.readableBytes();
}
@Override
protected void decode(ChannelHandlerContext ctx, ByteBuf in, List<Object> out) {
int start = ByteBufUtil.indexOf(startFlag, in);
if (start == -1) {
return;
}
start += startLength;
in.skipBytes(start - in.readerIndex());
int end = ByteBufUtil.indexOf(endFlag, in);
if (end == -1) {
return;
}
int len = end - start;
if (len < 1) {
return;
}
out.add(in.readRetainedSlice(len));
in.skipBytes(endLength);
}
}
Raw
EnclosedFrameDecoderTest.java
import io.netty.buffer.ByteBuf;
import io.netty.buffer.ByteBufUtil;
import io.netty.buffer.Unpooled;
import org.junit.jupiter.api.Assertions;
import org.junit.jupiter.api.Test;
import java.util.ArrayList;
public class EnclosedFrameDecoderTest {
@Test
public void normalFrame() throws Exception {
var decoder = new EnclosedFrameDecoder(new byte[]{0x00, 0x00}, new byte[]{0x00, 0x01});
var input = Unpooled.wrappedBuffer(new byte[] {
0x00, 0x00, 0x7c, (byte) 0xba, 0x04, 0x70, (byte) 0xa3, (byte) 0xf1, 0x69, 0x00, 0x01
});
var output = new ArrayList<>();
decoder.decode(null, input, output);
Assertions.assertEquals(1, output.size());
ByteBuf buf = (ByteBuf) output.get(0);
System.out.println(ByteBufUtil.hexDump(buf));
ByteBuf expected = Unpooled.wrappedBuffer(new byte[] {0x7c, (byte) 0xba, 0x04, 0x70, (byte) 0xa3, (byte) 0xf1, 0x69});
Assertions.assertEquals(expected, buf);
}
@Test
public void multipleNormalFrame() throws Exception {
var decoder = new EnclosedFrameDecoder(new byte[]{0x00, 0x00}, new byte[]{0x00, 0x01});
var input = Unpooled.wrappedBuffer(new byte[] {
0x00, 0x00, 0x04, 0x70, 0x00, 0x01,
0x00, 0x00, 0x05, 0x71, 0x00, 0x01
});
var output = new ArrayList<>();
decoder.decode(null, input, output);
Assertions.assertEquals(1, output.size());
ByteBuf buf = (ByteBuf) output.get(0);
System.out.println(ByteBufUtil.hexDump(buf));
ByteBuf expected = Unpooled.wrappedBuffer(new byte[] {0x04, 0x70});
Assertions.assertEquals(expected, buf);
}
@Test
public void multipleNormalFrameMultipleCall() throws Exception {
var decoder = new EnclosedFrameDecoder(new byte[]{0x00, 0x00}, new byte[]{0x00, 0x01});
var input = Unpooled.wrappedBuffer(new byte[] {
0x00, 0x00, 0x04, 0x70, 0x00, 0x01,
0x00, 0x00, 0x05, 0x71, 0x72, 0x00, 0x01,
0x00, 0x00, 0x06, 0x61, 0x00, 0x01,
});
var output = new ArrayList<>();
decoder.decode(null, input, output);
decoder.decode(null, input, output);
decoder.decode(null, input, output);
Assertions.assertEquals(3, output.size());
ByteBuf buf = (ByteBuf) output.get(0);
ByteBuf expected = Unpooled.wrappedBuffer(new byte[] {0x04, 0x70});
System.out.println(ByteBufUtil.hexDump(buf));
Assertions.assertEquals(expected, buf);
buf = (ByteBuf) output.get(1);
expected = Unpooled.wrappedBuffer(new byte[] {0x05, 0x71, 0x72});
System.out.println(ByteBufUtil.hexDump(buf));
Assertions.assertEquals(expected, buf);
buf = (ByteBuf) output.get(2);
expected = Unpooled.wrappedBuffer(new byte[] {0x06, 0x61});
System.out.println(ByteBufUtil.hexDump(buf));
Assertions.assertEquals(expected, buf);
}
@Test
public void multipleBetweenJunkBytes() throws Exception {
var decoder = new EnclosedFrameDecoder(new byte[]{0x00, 0x00}, new byte[]{0x00, 0x01});
var input = Unpooled.wrappedBuffer(new byte[] {
0x00, 0x00, 0x04, 0x70, 0x00, 0x01,
0x0E,
0x00, 0x00, 0x05, 0x71, 0x72, 0x00, 0x01,
0x3F, 0x2F,
0x00, 0x00, 0x06, 0x61, 0x00, 0x01,
});
var output = new ArrayList<>();
decoder.decode(null, input, output);
decoder.decode(null, input, output);
decoder.decode(null, input, output);
Assertions.assertEquals(3, output.size());
ByteBuf buf = (ByteBuf) output.get(0);
ByteBuf expected = Unpooled.wrappedBuffer(new byte[] {0x04, 0x70});
System.out.println(ByteBufUtil.hexDump(buf));
Assertions.assertEquals(expected, buf);
buf = (ByteBuf) output.get(1);
expected = Unpooled.wrappedBuffer(new byte[] {0x05, 0x71, 0x72});
System.out.println(ByteBufUtil.hexDump(buf));
Assertions.assertEquals(expected, buf);
buf = (ByteBuf) output.get(2);
expected = Unpooled.wrappedBuffer(new byte[] {0x06, 0x61});
System.out.println(ByteBufUtil.hexDump(buf));
Assertions.assertEquals(expected, buf);
}
@Test
public void leadingUnknownBytes() throws Exception {
var decoder = new EnclosedFrameDecoder(new byte[]{0x00, 0x00}, new byte[]{0x00, 0x01});
var input = Unpooled.wrappedBuffer(new byte[] {
(byte) 0x95, 0x51,
0x00, 0x00, 0x04, 0x70, 0x00, 0x01
});
var output = new ArrayList<>();
decoder.decode(null, input, output);
Assertions.assertEquals(1, output.size());
ByteBuf buf = (ByteBuf) output.get(0);
System.out.println(ByteBufUtil.hexDump(buf));
ByteBuf expected = Unpooled.wrappedBuffer(new byte[] {0x04, 0x70});
Assertions.assertTrue(ByteBufUtil.equals(expected, buf));
}
@Test
public void leadingPartialFrame() throws Exception {
var decoder = new EnclosedFrameDecoder(new byte[]{0x00, 0x00}, new byte[]{0x00, 0x01});
var input = Unpooled.wrappedBuffer(new byte[] {
(byte) 0x95, 0x51, 0x00, 0x01,
0x00, 0x00, 0x04, 0x70, 0x00, 0x01
});
var output = new ArrayList<>();
decoder.decode(null, input, output);
decoder.decode(null, input, output);
Assertions.assertEquals(1, output.size());
ByteBuf buf = (ByteBuf) output.get(0);
System.out.println(ByteBufUtil.hexDump(buf));
ByteBuf expected = Unpooled.wrappedBuffer(new byte[] {0x04, 0x70});
Assertions.assertTrue(ByteBufUtil.equals(expected, buf));
}
@Test
public void trailingUnknownBytes() throws Exception {
var decoder = new EnclosedFrameDecoder(new byte[]{0x00, 0x00}, new byte[]{0x00, 0x01});
var input = Unpooled.wrappedBuffer(new byte[] {
0x00, 0x00, 0x04, 0x70, 0x00, 0x01, 0x15, 0x51
});
var output = new ArrayList<>();
decoder.decode(null, input, output);
Assertions.assertEquals(1, output.size());
ByteBuf buf = (ByteBuf) output.get(0);
System.out.println(ByteBufUtil.hexDump(buf));
ByteBuf expected = Unpooled.wrappedBuffer(new byte[] {0x04, 0x70});
Assertions.assertTrue(ByteBufUtil.equals(expected, buf));
}
@Test
public void trailingUnknownBytes2() throws Exception {
var decoder = new EnclosedFrameDecoder(new byte[]{0x00, 0x00}, new byte[]{0x00, 0x01});
var input = Unpooled.wrappedBuffer(new byte[] {
0x00, 0x00, 0x04, 0x70, 0x00, 0x01, 0x15, 0x51
});
var output = new ArrayList<>();
decoder.decode(null, input, output);
decoder.decode(null, input, output);
Assertions.assertEquals(1, output.size());
ByteBuf buf = (ByteBuf) output.get(0);
System.out.println(ByteBufUtil.hexDump(buf));
ByteBuf expected = Unpooled.wrappedBuffer(new byte[] {0x04, 0x70});
Assertions.assertTrue(ByteBufUtil.equals(expected, buf));
}
@Test
public void trailingPartialFrame() throws Exception {
var decoder = new EnclosedFrameDecoder(new byte[]{0x00, 0x00}, new byte[]{0x00, 0x01});
var input = Unpooled.wrappedBuffer(new byte[] {
0x00, 0x00, 0x04, 0x70, 0x00, 0x01, 0x00, 0x00, 0x15, 0x51
});
var output = new ArrayList<>();
decoder.decode(null, input, output);
decoder.decode(null, input, output);
Assertions.assertEquals(1, output.size());
ByteBuf buf = (ByteBuf) output.get(0);
System.out.println(ByteBufUtil.hexDump(buf));
ByteBuf expected = Unpooled.wrappedBuffer(new byte[] {0x04, 0x70});
Assertions.assertTrue(ByteBufUtil.equals(expected, buf));
}
@Test
public void emptyFrame() throws Exception {
var decoder = new EnclosedFrameDecoder(new byte[]{0x00, 0x00}, new byte[]{0x00, 0x01});
var input = Unpooled.wrappedBuffer(new byte[] {
0x00, 0x00, 0x00, 0x01
});
var output = new ArrayList<>();
decoder.decode(null, input, output);
Assertions.assertEquals(0, output.size());
}
@Test
public void singleChar() throws Exception {
var decoder = new EnclosedFrameDecoder(new byte[]{'*'}, new byte[]{'#'});
var input = Unpooled.wrappedBuffer(new byte[] {
'*', 0x00, 0x01, 0x02, '#'
});
var output = new ArrayList<>();
decoder.decode(null, input, output);
Assertions.assertEquals(1, output.size());
ByteBuf buf = (ByteBuf) output.get(0);
System.out.println(ByteBufUtil.hexDump(buf));
ByteBuf expected = Unpooled.wrappedBuffer(new byte[] {0x00, 0x01, 0x02});
Assertions.assertTrue(ByteBufUtil.equals(expected, buf));
}
@Test
public void threeChar() throws Exception {
var decoder = new EnclosedFrameDecoder(new byte[]{0x00, 0x01, 0x02}, new byte[]{0x03, 0x02, 0x01});
var input = Unpooled.wrappedBuffer(new byte[] {
0x00, 0x01, 0x02, 0x0F, 0x0E, 0x0D, 0x03, 0x02, 0x01,
0x00, 0x01, 0x02, 0x1F, 0x1E, 0x1D, 0x03, 0x02, 0x01,
});
var output = new ArrayList<>();
decoder.decode(null, input, output);
decoder.decode(null, input, output);
decoder.decode(null, input, output);
Assertions.assertEquals(2, output.size());
ByteBuf buf = (ByteBuf) output.get(0);
ByteBuf expected = Unpooled.wrappedBuffer(new byte[] {0x0F, 0x0E, 0x0D});
System.out.println(ByteBufUtil.hexDump(buf));
Assertions.assertTrue(ByteBufUtil.equals(expected, buf));
buf = (ByteBuf) output.get(1);
expected = Unpooled.wrappedBuffer(new byte[] {0x1F, 0x1E, 0x1D});
System.out.println(ByteBufUtil.hexDump(buf));
Assertions.assertTrue(ByteBufUtil.equals(expected, buf));
}
}
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