Motivation:
There are few duplicated byte[] CRLF fields in code.
Modifications:
Removed duplicated fields as they could be inherited from parent encoder.
Result:
Less static fields.
Motivation:
There currently exists http.HttpUtil, http2.HttpUtil, and http.HttpHeaderUtil. Having 2 HttpUtil methods can be confusing and the utilty methods in the http package could be consolidated.
Modifications:
- Rename http2.HttpUtil to http2.HttpConversionUtil
- Move http.HttpHeaderUtil methods into http.HttpUtil
Result:
Consolidated utilities whose names don't overlap.
Fixes https://github.com/netty/netty/issues/4120
Motivation:
We noticed that the headers implementation in Netty for HTTP/2 uses quite a lot of memory
and that also at least the performance of randomly accessing a header is quite poor. The main
concern however was memory usage, as profiling has shown that a DefaultHttp2Headers
not only use a lot of memory it also wastes a lot due to the underlying hashmaps having
to be resized potentially several times as new headers are being inserted.
This is tracked as issue #3600.
Modifications:
We redesigned the DefaultHeaders to simply take a Map object in its constructor and
reimplemented the class using only the Map primitives. That way the implementation
is very concise and hopefully easy to understand and it allows each concrete headers
implementation to provide its own map or to even use a different headers implementation
for processing requests and writing responses i.e. incoming headers need to provide
fast random access while outgoing headers need fast insertion and fast iteration. The
new implementation can support this with hardly any code changes. It also comes
with the advantage that if the Netty project decides to add a third party collections library
as a dependency, one can simply plug in one of those very fast and memory efficient map
implementations and get faster and smaller headers for free.
For now, we are using the JDK's TreeMap for HTTP and HTTP/2 default headers.
Result:
- Significantly fewer lines of code in the implementation. While the total commit is still
roughly 400 lines less, the actual implementation is a lot less. I just added some more
tests and microbenchmarks.
- Overall performance is up. The current implementation should be significantly faster
for insertion and retrieval. However, it is slower when it comes to iteration. There is simply
no way a TreeMap can have the same iteration performance as a linked list (as used in the
current headers implementation). That's totally fine though, because when looking at the
benchmark results @ejona86 pointed out that the performance of the headers is completely
dominated by insertion, that is insertion is so significantly faster in the new implementation
that it does make up for several times the iteration speed. You can't iterate what you haven't
inserted. I am demonstrating that in this spreadsheet [1]. (Actually, iteration performance is
only down for HTTP, it's significantly improved for HTTP/2).
- Memory is down. The implementation with TreeMap uses on avg ~30% less memory. It also does not
produce any garbage while being resized. In load tests for GRPC we have seen a memory reduction
of up to 1.2KB per RPC. I summarized the memory improvements in this spreadsheet [1]. The data
was generated by [2] using JOL.
- While it was my original intend to only improve the memory usage for HTTP/2, it should be similarly
improved for HTTP, SPDY and STOMP as they all share a common implementation.
[1] https://docs.google.com/spreadsheets/d/1ck3RQklyzEcCLlyJoqDXPCWRGVUuS-ArZf0etSXLVDQ/edit#gid=0
[2] https://gist.github.com/buchgr/4458a8bdb51dd58c82b4
Motivation:
Even if its against the HTTP RFC there are situations where it may be useful to use other chars then US_ASCII in the headers. We should allow to make it possible by allow the user to override the how headers are encoded.
Modifications:
- Add encodeHeaders(...) method and so allow to override it.
Result:
It's now possible to encode headers with other charset then US_ASCII by just extend the encoder and override the encodeHeaders(...) method.
Motivation:
The commit 50e06442c3 changed the type of
the constants in HttpHeaders.Names and HttpHeaders.Values, making 4.1
backward-incompatible with 4.0.
It also introduces newer utility classes such as HttpHeaderUtil, which
deprecates most static methods in HttpHeaders. To ease the migration
between 4.1 and 5.0, we should deprecate all static methods that are
non-existent in 5.0, and provide proper counterpart.
Modification:
- Revert the changes in HttpHeaders.Names and Values
- Deprecate all static methods in HttpHeaders in favor of:
- HttpHeaderUtil
- the member methods of HttpHeaders
- AsciiString
- Add integer and date access methods to HttpHeaders for easier future
migration to 5.0
- Add HttpHeaderNames and HttpHeaderValues which provide standard HTTP
constants in AsciiString
- Deprecate HttpHeaders.Names and Values
- Make HttpHeaderValues.WEBSOCKET lowercased because it's actually
lowercased in all WebSocket versions but the oldest one
- Add RtspHeaderNames and RtspHeaderValues which provide standard RTSP
constants in AsciiString
- Deprecate RtspHeaders.*
- Do not use AsciiString.equalsIgnoreCase(CharSeq, CharSeq) if one of
the parameters are AsciiString
- Avoid using AsciiString.toString() repetitively
- Change the parameter type of some methods from String to
CharSequence
Result:
Backward compatibility is recovered. New classes and methods will make
the migration to 5.0 easier, once (Http|Rtsp)Header(Names|Values) are
ported to master.
Motivation:
The header class hierarchy and algorithm was improved on the master branch for versions 5.x. These improvments should be backported to the 4.1 baseline.
Modifications:
- cherry-pick the following commits from the master branch: 2374e17, 36b4157, 222d258
Result:
Header improvements in master branch are available in 4.1 branch.
Related: #2983
Motivation:
It is a well known idiom to write an empty buffer and add a listener to
its future to close a channel when the last byte has been written out:
ChannelFuture f = channel.writeAndFlush(Unpooled.EMPTY_BUFFER);
f.addListener(ChannelFutureListener.CLOSE);
When HttpObjectEncoder is in the pipeline, this still works, but it
silently raises an IllegalStateException, because HttpObjectEncoder does
not allow writing a ByteBuf when it is expecting an HttpMessage.
Modifications:
- Handle an empty ByteBuf specially in HttpObjectEncoder, so that
writing an empty buffer does not fail even if the pipeline contains an
HttpObjectEncoder
- Add a test
Result:
An exception is not triggered anymore by HttpObjectEncoder, when a user
attempts to write an empty buffer.
Motivation:
Due to integer overflow bug, writes of FileRegions to http server pipeline (eg like one from HttpStaticFileServer example) with length greater than Integer.MAX_VALUE are ignored in 1/2 of cases (ie no data gets sent to client)
Modification:
Correctly handle chunk sized > Integer.MAX_VALUE
Result:
Be able to use FileRegion > Integer.MAX_VALUE when using chunked encoding.
encode of chunked content is not the most common pattern so moving it to an extra method makes it possible to inline the rest as it is a smaller method now.
- write() now accepts a ChannelPromise and returns ChannelFuture as most
users expected. It makes the user's life much easier because it is
now much easier to get notified when a specific message has been
written.
- flush() does not create a ChannelPromise nor returns ChannelFuture.
It is now similar to what read() looks like.
I must admit MesageList was pain in the ass. Instead of forcing a
handler always loop over the list of messages, this commit splits
messageReceived(ctx, list) into two event handlers:
- messageReceived(ctx, msg)
- mmessageReceivedLast(ctx)
When Netty reads one or more messages, messageReceived(ctx, msg) event
is triggered for each message. Once the current read operation is
finished, messageReceivedLast() is triggered to tell the handler that
the last messageReceived() was the last message in the current batch.
Similarly, for outbound, write(ctx, list) has been split into two:
- write(ctx, msg)
- flush(ctx, promise)
Instead of writing a list of message with a promise, a user is now
supposed to call write(msg) multiple times and then call flush() to
actually flush the buffered messages.
Please note that write() doesn't have a promise with it. You must call
flush() to get notified on completion. (or you can use writeAndFlush())
Other changes:
- Because MessageList is completely hidden, codec framework uses
List<Object> instead of MessageList as an output parameter.
The API changes made so far turned out to increase the memory footprint
and consumption while our intention was actually decreasing them.
Memory consumption issue:
When there are many connections which does not exchange data frequently,
the old Netty 4 API spent a lot more memory than 3 because it always
allocates per-handler buffer for each connection unless otherwise
explicitly stated by a user. In a usual real world load, a client
doesn't always send requests without pausing, so the idea of having a
buffer whose life cycle if bound to the life cycle of a connection
didn't work as expected.
Memory footprint issue:
The old Netty 4 API decreased overall memory footprint by a great deal
in many cases. It was mainly because the old Netty 4 API did not
allocate a new buffer and event object for each read. Instead, it
created a new buffer for each handler in a pipeline. This works pretty
well as long as the number of handlers in a pipeline is only a few.
However, for a highly modular application with many handlers which
handles connections which lasts for relatively short period, it actually
makes the memory footprint issue much worse.
Changes:
All in all, this is about retaining all the good changes we made in 4 so
far such as better thread model and going back to the way how we dealt
with message events in 3.
To fix the memory consumption/footprint issue mentioned above, we made a
hard decision to break the backward compatibility again with the
following changes:
- Remove MessageBuf
- Merge Buf into ByteBuf
- Merge ChannelInboundByte/MessageHandler and ChannelStateHandler into ChannelInboundHandler
- Similar changes were made to the adapter classes
- Merge ChannelOutboundByte/MessageHandler and ChannelOperationHandler into ChannelOutboundHandler
- Similar changes were made to the adapter classes
- Introduce MessageList which is similar to `MessageEvent` in Netty 3
- Replace inboundBufferUpdated(ctx) with messageReceived(ctx, MessageList)
- Replace flush(ctx, promise) with write(ctx, MessageList, promise)
- Remove ByteToByteEncoder/Decoder/Codec
- Replaced by MessageToByteEncoder<ByteBuf>, ByteToMessageDecoder<ByteBuf>, and ByteMessageCodec<ByteBuf>
- Merge EmbeddedByteChannel and EmbeddedMessageChannel into EmbeddedChannel
- Add SimpleChannelInboundHandler which is sometimes more useful than
ChannelInboundHandlerAdapter
- Bring back Channel.isWritable() from Netty 3
- Add ChannelInboundHandler.channelWritabilityChanges() event
- Add RecvByteBufAllocator configuration property
- Similar to ReceiveBufferSizePredictor in Netty 3
- Some existing configuration properties such as
DatagramChannelConfig.receivePacketSize is gone now.
- Remove suspend/resumeIntermediaryDeallocation() in ByteBuf
This change would have been impossible without @normanmaurer's help. He
fixed, ported, and improved many parts of the changes.
- Fixes#1282 (not perfectly, but to the extent it's possible with the current API)
- Add AddressedEnvelope and DefaultAddressedEnvelope
- Make DatagramPacket extend DefaultAddressedEnvelope<ByteBuf, InetSocketAddress>
- Rename ByteBufHolder.data() to content() so that a message can implement both AddressedEnvelope and ByteBufHolder (DatagramPacket does) without introducing two getter methods for the content
- Datagram channel implementations now understand ByteBuf and ByteBufHolder as a message with unspecified remote address.
- Rename ChannelHandlerAdapter to ChannelDuplexHandler
- Add ChannelHandlerAdapter that implements only ChannelHandler
- Rename CombinedChannelHandler to CombinedChannelDuplexHandler and
improve runtime validation
- Remove ChannelInbound/OutboundHandlerAdapter which are not useful
- Make ChannelOutboundByteHandlerAdapter similar to
ChannelInboundByteHandlerAdapter
- Make the tail and head handler of DefaultChannelPipeline accept both
bytes and messages. ChannelHandlerContext.hasNext*() were removed
because they always return true now.
- Removed various unnecessary null checks.
- Correct method/field names:
inboundBufferSuspended -> channelReadSuspended
- Rename message types for clarity
- HttpMessage -> FullHttpMessage
- HttpHeader -> HttpMessage
- HttpRequest -> FullHttpRequest
- HttpResponse -> FulllHttpResponse
- HttpRequestHeader -> HttpRequest
- HttpResponseHeader -> HttpResponse
- HttpContent now extends ByteBufHolder; no more content() method
- Make HttpHeaders abstract, make its header access methods public, and
add DefaultHttpHeaders
- Header accessor methods in HttpMessage and LastHttpContent are
replaced with HttpMessage.headers() and
LastHttpContent.trailingHeaders(). Both methods return HttpHeaders.
- Remove setters wherever possible and remove 'get' prefix
- Instead of calling setContent(), a user can either specify the content
when constructing a message or write content into the buffer.
(e.g. m.content().writeBytes(...))
- Overall cleanup & fixes
This commit tries to simplify the handling of Http easier and more consistent. This has a effect of many channges. Including:
- HttpMessage was renamed to HttpHeader and the setContent and getContent methods were removed
- HttpChunk was renamed to HttpContent
- HttpChunkTrailer was renamed to LastHttpContent
- HttpCodecUtil was merged into HttpHeaders
Now a "complete" Http message (request or response) contains of the following parts:
- HttpHeader (HttpRequestHeader or HttpResponseHeader)
- 0 - n HttpContent objects which contains parts of the content of the message
- 1 LastHttpContent which marks the end of the message and contains the remaining data of the content
I also changed the sematic of HttpResponse and HttpRequest, these now represent a "complete" message which contains the HttpHeader and the HttpLastContent, and so can be used to eeasily send requests. The HttpMessageAggregator was renamed to HttpObjectAggregator and produce HttpResponse / HttpRequest message.
