Motivation:
The responsibility for retaining the settings values and enforcing the settings constraints is spread out in different areas of the code and may be initialized with different values than the default specified in the RFC. This should not be allowed by default and interfaces which are responsible for maintaining/enforcing settings state should clearly indicate the restrictions that they should only be set by the codec upon receipt of a SETTINGS ACK frame.
Modifications:
- Encoder, Decoder, and the Headers Encoder/Decoder no longer expose public constructors that allow the default settings to be changed.
- Http2HeadersDecoder#maxHeaderSize() exists to provide some bound when headers/continuation frames are being aggregated. However this is roughly the same as SETTINGS_MAX_HEADER_LIST_SIZE (besides the 32 byte octet for each header field) and can be used instead of attempting to keep the two independent values in sync.
- Encoding headers now enforces SETTINGS_MAX_HEADER_LIST_SIZE at the octect level. Previously the header encoder compared the number of header key/value pairs against SETTINGS_MAX_HEADER_LIST_SIZE instead of the number of octets (plus 32 bytes overhead).
- DefaultHttp2ConnectionDecoder#onData calls shouldIgnoreHeadersOrDataFrame but may swallow exceptions from this method. This means a STREAM_RST frame may not be sent when it should for an unknown stream and thus violate the RFC. The exception is no longer swallowed.
Result:
Default settings state is enforced and interfaces related to settings state are clarified.
Motivation:
Some codecs should be considered unstable as these are relative new. For this purpose we should introduce an annotation which these codecs should us to be marked as unstable in terms of API.
Modifications:
- Add UnstableApi annotation and use it on codecs that are not stable
- Move http2.hpack to http2.internal.hpack as it is internal.
Result:
Better document unstable APIs.
Motivation:
HTTP/2 codec was implemented in master branch.
Since, master is not yet stable and will be some time before it gets released, backporting it to 4.1, enables people to use the codec with a stable netty version.
Modification:
The code has been copied from master branch as is, with minor modifications to suit the `ChannelHandler` API in 4.x.
Apart from that change, there are two backward incompatible API changes included, namely,
- Added an abstract method:
`public abstract Map.Entry<CharSequence, CharSequence> forEachEntry(EntryVisitor<CharSequence> visitor)
throws Exception;`
to `HttpHeaders` and implemented the same in `DefaultHttpHeaders` as a delegate to the internal `TextHeader` instance.
- Added a method:
`FullHttpMessage copy(ByteBuf newContent);`
in `FullHttpMessage` with the implementations copied from relevant places in the master branch.
- Added missing abstract method related to setting/adding short values to `HttpHeaders`
Result:
HTTP/2 codec can be used with netty 4.1
