protected override void Decode(IChannelHandlerContext context, IByteBuffer buffer, List <object> output)
{
if (SharedConstants.False < (uint)Volatile.Read(ref _resetRequested))
{
ResetNow();
}
switch (_currentState)
{
case State.SkipControlChars:
// Fall through
case State.ReadInitial:
{
try
{
AppendableCharSequence line = _lineParser.Parse(buffer);
if (line is null)
{
return;
}
AsciiString[] initialLine = SplitInitialLine(line);
if ((uint)initialLine.Length < 3u)
{
// Invalid initial line - ignore.
_currentState = State.SkipControlChars;
return;
}
_message = CreateMessage(initialLine);
_currentState = State.ReadHeader;
goto case State.ReadHeader; // Fall through
}
catch (Exception e)
{
output.Add(InvalidMessage(buffer, e));
return;
}
}
case State.ReadHeader:
{
try
{
State?nextState = ReadHeaders(buffer);
if (nextState is null)
{
return;
}
_currentState = nextState.Value;
switch (nextState.Value)
{
case State.SkipControlChars:
{
// fast-path
// No content is expected.
output.Add(_message);
output.Add(EmptyLastHttpContent.Default);
ResetNow();
return;
}
case State.ReadChunkSize:
{
if (!_chunkedSupported)
{
ThrowHelper.ThrowArgumentException_ChunkedMsgNotSupported();
}
// Chunked encoding - generate HttpMessage first. HttpChunks will follow.
output.Add(_message);
return;
}
default:
{
// <a href="https://tools.ietf.org/html/rfc7230#section-3.3.3">RFC 7230, 3.3.3</a> states that if a
// request does not have either a transfer-encoding or a content-length header then the message body
// length is 0. However for a response the body length is the number of octets received prior to the
// server closing the connection. So we treat this as variable length chunked encoding.
long length = ContentLength();
if (0u >= (uint)length || length == -1 && IsDecodingRequest())
{
output.Add(_message);
output.Add(EmptyLastHttpContent.Default);
ResetNow();
return;
}
Debug.Assert(nextState.Value == State.ReadFixedLengthContent ||
nextState.Value == State.ReadVariableLengthContent);
output.Add(_message);
if (nextState == State.ReadFixedLengthContent)
{
// chunkSize will be decreased as the READ_FIXED_LENGTH_CONTENT state reads data chunk by chunk.
_chunkSize = length;
}
// We return here, this forces decode to be called again where we will decode the content
return;
}
}
}
catch (Exception exception)
{
output.Add(InvalidMessage(buffer, exception));
return;
}
}
case State.ReadVariableLengthContent:
{
// Keep reading data as a chunk until the end of connection is reached.
int toRead = Math.Min(buffer.ReadableBytes, _maxChunkSize);
if (toRead > 0)
{
IByteBuffer content = buffer.ReadRetainedSlice(toRead);
output.Add(new DefaultHttpContent(content));
}
return;
}
case State.ReadFixedLengthContent:
{
int readLimit = buffer.ReadableBytes;
// Check if the buffer is readable first as we use the readable byte count
// to create the HttpChunk. This is needed as otherwise we may end up with
// create an HttpChunk instance that contains an empty buffer and so is
// handled like it is the last HttpChunk.
//
// See https://github.com/netty/netty/issues/433
if (0u >= (uint)readLimit)
{
return;
}
int toRead = Math.Min(readLimit, _maxChunkSize);
if (toRead > _chunkSize)
{
toRead = (int)_chunkSize;
}
IByteBuffer content = buffer.ReadRetainedSlice(toRead);
_chunkSize -= toRead;
if (0ul >= (ulong)_chunkSize)
{
// Read all content.
output.Add(new DefaultLastHttpContent(content, ValidateHeaders));
ResetNow();
}
else
{
output.Add(new DefaultHttpContent(content));
}
return;
}
// everything else after this point takes care of reading chunked content. basically, read chunk size,
// read chunk, read and ignore the CRLF and repeat until 0
case State.ReadChunkSize:
{
try
{
AppendableCharSequence line = _lineParser.Parse(buffer);
if (line is null)
{
return;
}
int size = GetChunkSize(line.ToAsciiString());
_chunkSize = size;
if (0u >= (uint)size)
{
_currentState = State.ReadChunkFooter;
return;
}
_currentState = State.ReadChunkedContent;
goto case State.ReadChunkedContent; // fall-through
}
catch (Exception e)
{
output.Add(InvalidChunk(buffer, e));
return;
}
}
case State.ReadChunkedContent:
{
Debug.Assert(_chunkSize <= int.MaxValue);
int toRead = Math.Min((int)_chunkSize, _maxChunkSize);
toRead = Math.Min(toRead, buffer.ReadableBytes);
if (0u >= (uint)toRead)
{
return;
}
IHttpContent chunk = new DefaultHttpContent(buffer.ReadRetainedSlice(toRead));
_chunkSize -= toRead;
output.Add(chunk);
if (_chunkSize != 0)
{
return;
}
_currentState = State.ReadChunkDelimiter;
goto case State.ReadChunkDelimiter; // fall-through
}
case State.ReadChunkDelimiter:
{
int wIdx = buffer.WriterIndex;
int rIdx = buffer.ReaderIndex;
// TODO ForEachByte
while (wIdx > rIdx)
{
byte next = buffer.GetByte(rIdx++);
if (next == HttpConstants.LineFeed)
{
_currentState = State.ReadChunkSize;
break;
}
}
_ = buffer.SetReaderIndex(rIdx);
return;
}
case State.ReadChunkFooter:
{
try
{
ILastHttpContent lastTrialer = ReadTrailingHeaders(buffer);
if (lastTrialer is null)
{
return;
}
output.Add(lastTrialer);
ResetNow();
return;
}
catch (Exception exception)
{
output.Add(InvalidChunk(buffer, exception));
return;
}
}
case State.BadMessage:
{
// Keep discarding until disconnection.
_ = buffer.SkipBytes(buffer.ReadableBytes);
break;
}
case State.Upgraded:
{
int readableBytes = buffer.ReadableBytes;
if (readableBytes > 0)
{
// Keep on consuming as otherwise we may trigger an DecoderException,
// other handler will replace this codec with the upgraded protocol codec to
// take the traffic over at some point then.
// See https://github.com/netty/netty/issues/2173
output.Add(buffer.ReadBytes(readableBytes));
}
break;
}
}
}