Motivation:
At the moment all methods in `ChannelHandler` declare `throws Exception` as part of their method signature. While this is fine for methods that handle inbound events it is quite confusing for methods that handle outbound events. This comes due the fact that these methods also take a `ChannelPromise` which actually need to be fullfilled to signal back either success or failure. Define `throws...` for these methods is confusing at best. We should just always require the implementation to use the passed in promise to signal back success or failure. Doing so also clears up semantics in general. Due the fact that we can't "forbid" throwing `RuntimeException` we still need to handle this in some way tho. In this case we should just consider it a "bug" and so log it and close the `Channel` in question. The user should never have an exception "escape" their implementation and just use the promise. This also clears up the ownership of the passed in message etc.
As `flush(ChannelHandlerContext)` and `read(ChannelHandlerContext)` don't take a `ChannelPromise` as argument this also means that these methods can never produce an error. This makes kind of sense as these really are just "signals" for the underlying transports to do something. For `RuntimeException` the same rule is used as for other outbound event handling methods, which is logging and closing the `Channel`.
Motifications:
- Remove `throws Exception` from signature
- Adjust code to not throw and just notify the promise directly
- Adjust unit tests
Result:
Much cleaner API and semantics.
Motivation:
This special case implementation of Promise / Future requires the implementations responsible for completing the promise to have knowledge of this class to provide value. It also requires that the implementations are able to provide intermediate status while the work is being done. Even throughout the core of Netty it is not really supported most of the times and so just brings more complexity without real gain.
Let's remove it completely which is better then only support it sometimes.
Modifications:
Remove Progressive* API
Result:
Code cleanup.... Fixes https://github.com/netty/netty/issues/8519
Motivation:
NullChecks resulting in a NullPointerException or IllegalArgumentException, numeric ranges (>0, >=0) checks, not empty strings/arrays checks must never be anonymous but with the parameter or variable name which is checked. They must be specific and should not be done with an "OR-Logic" (if a == null || b == null) throw new NullPointerEx.
Modifications:
* import static relevant checks
* Replace manual checks with ObjectUtil methods
Result:
All checks needed are done with ObjectUtil, some exception texts are improved.
Fixes#11170
Motivation:
At the moment we only expose close(...) methods that take a Channel as paramater. This can be problematic as the write will start at the end of the pipeline which may contain ChannelOutboundHandler implementations that not expect WebSocketFrame objects. We should better also support to pass in a ChannelHandlerContext as starting point for the write which ensures that the WebSocketFrame objects will be handled correctly from this position of the pipeline.
Modifications:
- Add new close(...) methods that take a ChannelHandlerContext
- Add javadoc sentence to point users to the new methods.
Result:
Be able to "start" the close at the right position in the pipeline.
Motivation:
People may use the object serialisation example as a vehicle to test out sending their own objects across the wire.
If those objects are not actually serialisable for some reason, then we need to let the exception propagate so that this becomes obvious to people.
Modification:
Add a listener to the future that sends the first serialisable message, so that we ensure that any exceptions that shows up during serialisation becomes visible.
Without this, the state of the future that sent the first message was never checked or inspected anywhere.
Result:
Serialisation bugs in code derived from the Object Echo example are much easier to diagnose.
This fixes#10777
Motivation:
HTTP is a plaintext protocol which means that someone may be able
to eavesdrop the data. To prevent this, HTTPS should be used whenever
possible. However, maintaining using https:// in all URLs may be
difficult. The nohttp tool can help here. The tool scans all the files
in a repository and reports where http:// is used.
Modifications:
- Added nohttp (via checkstyle) into the build process.
- Suppressed findings for the websites
that don't support HTTPS or that are not reachable
Result:
- Prevent using HTTP in the future.
- Encourage users to use HTTPS when they follow the links they found in
the code.
Motivation:
LGTM reports multiple issues. They need to be triaged,
and real ones should be fixed.
Modifications:
- Fixed multiple issues reported by LGTM, such as redundant conditions,
resource leaks, typos, possible integer overflows.
- Suppressed false-positives.
- Added a few testcases.
Result:
Fixed several possible issues, get rid of false alarms in the LGTM report.
Motivation:
MQTT Specification version 5 was released over a year ago,
netty-codec-mqtt should be changed to support it.
Modifications:
Added more message and header types in `io.netty.handler.codec.mqtt`
package in `netty-coded-mqtt` subproject,
changed `MqttEncoder` and `MqttDecoder` to handle them properly,
added attribute `NETTY_CODEC_MQTT_VERSION` to track protocol version
Result:
`netty-codec-mqtt` supports both MQTT5 and MQTT3 now.
Motivation:
We don't have example code for smtp.
Modifications:
Add SmtpClient and SmtpClientHandler.
Result:
Provide an example for developers who want to write a smtp client.
Motivation:
This request only has headers frame, it should set endOfStream flag, or
it will never get a response.
Modifications:
Set endOfStream=true in header frame.
Result:
Http2FrameClient can get a response now.
Motivation:
Current implementation `StompSubframeEncoder` can encode `StompFrame` into several separate chunks or encode separately `StompHeadersSubframe` and `StompContentSubframe`. But some client libraries (e.g. stomp.js) do not support aggregation.
Modification:
Add StompWebSocketFrameEncoder for integration between origin stomp suframe encoder and `ContinuationWebSocketFrame` to support chunks on transport level.
Result:
Fixes#10261
Motivation:
[DNS-over-TLS (DoT)](https://tools.ietf.org/html/rfc7858.html) encrypts DNS queries and sends it over TLS connection to make sure queries are secure in transit.
[TCP DNS](https://tools.ietf.org/html/rfc7766) sends DNS queries over TCP connection (unencrypted).
Modification:
Add DNS-over-TLS (DoT) Client Example which uses TLSv1.2 and TLSv1.3.
Add TCP DNS Client Example
Result:
DNS-over-TLS (DoT) Client Example
TCP DNS Client Example
Motivation:
Add support for HAProxyMessageEncoder.
This should help java based HAProxy server implementations propagate proxy information.
Modification:
Add public constructors for `HAProxyMessage`, `HAProxyTLV`, `HAProxySSLTLV`.
Add additional argument checks for `HAProxyMessage` and modify exceptions thrown when creating via public constructors directly.
Introduce a `@Sharable` `HAProxyMessageEncoder` which encodes a `HAProxyMessage` into a byte array.
Add an example `HAProxyServer` and `HAProxyClient` to `io.netty.example`
Result:
Fixes#10164
Motivation:
Often people want to use `stomp-codec` with WebSocket transport or other but cannot figure out how can do this staff on Netty.
Modification:
Create example for demonstrating integration between STOMP and WebSocket.
Inspired by https://github.com/jmesnil/stomp-websocket
Result:
Fixes#9383
**Motivation:**
When I was previously working on a project using Netty's HTTP/2 support, I used the newer frames approach but I struggled to find any good examples or documentation online. I did, however, see a few people ask the same (or similar) questions as me on StackOverflow and a couple of older Netty Github issues.
Reading issue [9733](https://github.com/netty/netty/issues/9733) therefore prompted me to pull together a few bits of code into this HTTP/2 frame client example.
**Modification:**
Populated the previously-empty `example/src/main/java/io/netty/example/http2/helloworld/frame/client/` folder with a HTTP/2 frame client example.
**Result:**
Gives a clear example of how the newer HTTP/2 support can be used for Netty clients.
Motivation:
At the moment the next / prev references are not set to "null" in the DefaultChannelHandlerContext once the ChannelHandler is removed. This is bad as it basically let users still use the ChannelHandlerContext of a ChannelHandler after it is removed and may produce very suprising behaviour.
Modifications:
- Fail if someone tries to use the ChannelHandlerContext once the ChannelHandler was removed (for outbound operations fail the promise, for inbound fire the error through the ChannelPipeline)
- Fix some handlers to ensure we not use the ChannelHandlerContext after the handler was removed
- Adjust DefaultChannelPipeline / DefaultChannelHandlerContext to fixes races with removal / replacement of handlers
Result:
Cleanup behaviour and make it more predictable for pipeline modifications
Motivation:
java.io.File.listFiles() may return null and cause a unexpected NPE.
Modification:
Extract a local variable from the return value of File.listFiles() and do a null check.
Result:
Fix the potential NPE.
Motivation:
In next major version of netty users should use ChannelHandler everywhere. We should ensure we do the same
Modifications:
Replace usage of deprecated classes / interfaces with ChannelHandler
Result:
Use non-deprecated code
Motivation:
Since "Http2ClientInitializer" creates a new SSLContext Handler without specifying Host, Netty does not add SNI Extension in TLS Client Hello request and the request fails if the server uses SNI to establish TLS Connection.
Modification:
Specified Host while creating a new SSLContext Handler in "Http2ClientInitializer".
Result:
Netty adds SNI Extension of the Host Specified in new SSLContext Handler and sends it with TLS Client Hello request.
Fixes#9815.
Motivation:
ByteToMessageDecoder requires using an intermediate List to put results into. This intermediate list adds overhead (memory/CPU) which grows as the number of objects increases. This overhead can be avoided by directly propagating events through the ChannelPipeline via ctx.fireChannelRead(...). This also makes the semantics more clear and allows us to keep track if we need to call ctx.read() in all cases.
Modifications:
- Remove List from the method signature of ByteToMessageDecoder.decode(...) and decodeLast(...)
- Adjust all sub-classes
- Adjust unit tests
- Fix javadocs.
Result:
Adjust ByteToMessageDecoder as noted in https://github.com/netty/netty/issues/8525.
Motivation
Per javadoc in 4.1.x SimpleChannelInboundHandler:
"Please keep in mind that channelRead0(ChannelHandlerContext, I) will be
renamed to messageReceived(ChannelHandlerContext, I) in 5.0."
Modifications
Rename aforementioned method and all references/overrides.
Result
Method is renamed.
Motivation:
In many places Netty uses Unpooled.buffer(0) while should use EMPTY_BUFFER. We can't change this due to back compatibility in the constructors but can use Unpooled.EMPTY_BUFFER in some cases to ensure we not allocate at all. In others we can directly use the allocator either from the Channel / ChannelHandlerContext or the request / response.
Modification:
- Use Unpooled.EMPTY_BUFFER where possible
- Use allocator where possible
Result:
Fixes#9345 for websockets and http package
Motivation:
Recently I'm going to build MQTT broker and client based on Netty. I had MQTT encoder and decoder founded, while no basic examples. So I'm going to share my simple heartBeat MQTT broker and client as an example.
Modification:
New MQTT heartBeat example under io.netty.example/mqtt/heartBeat/.
Result:
Client would send CONNECT and PINGREQ(heartBeat message).
- CONNECT: once channel active
- PINGREQ: once IdleStateEvent triggered, which is 20 seconds in this example
Client would discard all messages it received.
MQTT broker could handle CONNECT, PINGREQ and DISCONNECT messages.
- CONNECT: send CONNACK back
- PINGREQ: send PINGRESP back
- DISCONNECT: close the channel
Broker would close the channel if 2 heartBeat lost, which set to 45 seconds in this example.
Motivation:
Some methods that either override others or are implemented as part of implementation an interface did miss the `@Override` annotation
Modifications:
Add missing `@Override`s
Result:
Code cleanup
Motivation:
In the past we had the following class hierarchy:
Http2ConnectionHandler --- Http2FrameCodec -- Http2MultiplexCodec
This hierarchy makes it impossible to plug in any code that would like to act on Http2Frame and Http2StreamFrame which can be quite useful for various situations (like metrics, logging etc). Beside this it also made the implementtion very hacky. To allow easier maintainance and also allow more flexible costumizations we should split Http2MultiplexCodec and Http2FrameCode.
Modifications:
- Introduce Http2MultiplexHandler (which is a replacement for Http2MultiplexCodec when used together with Http2FrameCodec)
- Mark Http2MultiplexCodecBuilder and Http2MultiplexCodec as deprecated. People should use Http2FrameCodecBuilder / Http2FrameCodec together with Http2MultiplexHandlder in the future
- Adjust / Add tests
- Adjust examples
Result:
More flexible usage possible and less hacky / coupled implementation for http2 multiplexing
Motivation:
The io.netty.example.http2.helloworld.client.Http2Client example should work in the h2c (HTTP2 cleartext - non-TLS) mode, which is the default for this example unless you set a -Dssl VM param. As we do not set the HOST header some servers do reject the upgrade request.
Modifications:
Set the HOST header
Result:
Fixes https://github.com/netty/netty/issues/9115.
Motivation:
As brought up in https://github.com/netty/netty/issues/8998, JKS can be substantially faster than pkcs12, JDK's new default. Without an option to set the KeyStore type you must change the configuration of the entire JVM which is impractical.
Modification:
- Allow to specify KeyStore type
- Add test case
Result:
Fixes https://github.com/netty/netty/issues/8998.
Motivation:
HttpHelloWorldServer example works incorrect for HTTP 1.1, the value of header connection is always set to close for each request.
Modification:
Correctly set header
Result:
Fixed HttpHelloWorldServerHandler for handling HTTP 1.0/1.1
Motivation:
"Connection: close" header should be specified each time we're going
to close an underlying TCP connection when sending HTTP/1.1 reply.
Modifications:
Introduces changes made in #8914 for the following examples:
* WebSocket index page and WebSocket server handler
* HelloWorld server
* SPDY server handler
* HTTP/1.1 server handler from HTTP/2 HelloWorld example
* HTTP/1.1 server handler from tiles example
Result:
Keep-Alive connections management conforms with RFCs.
Motivation:
In 42742e233f we already added default methods to Channel*Handler and deprecated the Adapter classes to simplify the class hierarchy. With this change we go even further and merge everything into just ChannelHandler. This simplifies things even more in terms of class-hierarchy.
Modifications:
- Merge ChannelInboundHandler | ChannelOutboundHandler into ChannelHandler
- Adjust code to just use ChannelHandler
- Deprecate old interfaces.
Result:
Cleaner and simpler code in terms of class-hierarchy.
Motivation:
We can just use a local variable in HttpUploadServerHandler and so make the example code a bit cleaner.
Modifications:
Use local variable.
Result:
Fixes https://github.com/netty/netty/issues/8892.
Motivation:
As we now us java8 as minimum java version we can deprecate ChannelInboundHandlerAdapter / ChannelOutboundHandlerAdapter and just move the default implementations into the interfaces. This makes things a bit more flexible for the end-user and also simplifies the class-hierarchy.
Modifications:
- Mark ChannelInboundHandlerAdapter and ChannelOutboundHandlerAdapter as deprecated
- Add default implementations to ChannelInboundHandler / ChannelOutboundHandler
- Refactor our code to not use ChannelInboundHandlerAdapter / ChannelOutboundHandlerAdapter anymore
Result:
Cleanup class-hierarchy and make things a bit more flexible.
Motivation:
Simple rules:
* close the connection when sending any error
* specify "Connection: close" header when closing the connection
* successful responses should keep the connection intact when otherwise is not requested by the client
Modifications:
* "send response and cleanup the connection" logic moved to a helper
* for all successful responses set "Content-Lenght" header
* do not specify "Connection: Keep-Alive" header as far it's a default for HTTP/1.1
* set "Connection: close" header when necessary
Result:
Keep-Alive connections management is inlined with RFCs.
Motivation:
SPDY has been superseded by HTTP/2. Chrome has dropped support in 2016 and GFE no longer negociate it.
Modifications:
* drop codec
* drop examples
* drop constants from `ApplicationProtocolNames`
Result:
SPDY support dropped from Netty 5
Motivation:
We can just use Objects.requireNonNull(...) as a replacement for ObjectUtil.checkNotNull(....)
Modifications:
- Use Objects.requireNonNull(...)
Result:
Less code to maintain.
Motivation:
In most cases, HttpMethod instance is built from the factory method and the same instance is taken for known Http Methods. So we can implement fast path for equals().
Modification:
Replace == checks with HttpMethod.equals;
Use this == o within HttpMethod.equals;
Replaced known new HttpMethod with HttpMethod.valueOf;
Result:
Comparisons should be a bit faster in some cases.
Motivation:
We can use lambdas now as we use Java8.
Modification:
use lambda function for all package, #8751 only migrate transport package.
Result:
Code cleanup.
Motivation:
We need to update to a new checkstyle plugin to allow the usage of lambdas.
Modifications:
- Update to new plugin version.
- Fix checkstyle problems.
Result:
Be able to use checkstyle plugin which supports new Java syntax.
* Decouble EventLoop details from the IO handling for each transport to allow easy re-use of code and customization
Motiviation:
As today extending EventLoop implementations to add custom logic / metrics / instrumentations is only possible in a very limited way if at all. This is due the fact that most implementations are final or even package-private. That said even if these would be public there are the ability to do something useful with these is very limited as the IO processing and task processing are very tightly coupled. All of the mentioned things are a big pain point in netty 4.x and need improvement.
Modifications:
This changeset decoubled the IO processing logic from the task processing logic for the main transport (NIO, Epoll, KQueue) by introducing the concept of an IoHandler. The IoHandler itself is responsible to wait for IO readiness and process these IO events. The execution of the IoHandler itself is done by the SingleThreadEventLoop as part of its EventLoop processing. This allows to use the same EventLoopGroup (MultiThreadEventLoupGroup) for all the mentioned transports by just specify a different IoHandlerFactory during construction.
Beside this core API change this changeset also allows to easily extend SingleThreadEventExecutor / SingleThreadEventLoop to add custom logic to it which then can be reused by all the transports. The ideas are very similar to what is provided by ScheduledThreadPoolExecutor (that is part of the JDK). This allows for example things like:
* Adding instrumentation / metrics:
* how many Channels are registered on an SingleThreadEventLoop
* how many Channels were handled during the IO processing in an EventLoop run
* how many task were handled during the last EventLoop / EventExecutor run
* how many outstanding tasks we have
...
...
* Implementing custom strategies for choosing the next EventExecutor / EventLoop to use based on these metrics.
* Use different Promise / Future / ScheduledFuture implementations
* decorate Runnable / Callables when submitted to the EventExecutor / EventLoop
As a lot of functionalities are folded into the MultiThreadEventLoopGroup and SingleThreadEventLoopGroup this changeset also removes:
* AbstractEventLoop
* AbstractEventLoopGroup
* EventExecutorChooser
* EventExecutorChooserFactory
* DefaultEventLoopGroup
* DefaultEventExecutor
* DefaultEventExecutorGroup
Result:
Fixes https://github.com/netty/netty/issues/8514 .
Motivation:
PlatformDependent.newConcurrentHashMap() is no longer needed so it could be easily removed and new ConcurrentHashMap<>() inlined instead of invoking PlatformDependent.newConcurrentHashMap().
Modification:
Use ConcurrentHashMap provided by the JDK directly.
Result:
Less code to maintain.
Motivation:
We can use the diamond operator these days.
Modification:
Use diamond operator whenever possible.
Result:
More modern code and less boiler-plate.
Motivation:
Since Java 7 we can automatically close resources in try () construction.
Modification:
Changed all try catches in the code with autoclose try (resource)
Result:
Less boiler-plate
Motiviation:
Because of how we implemented the registration / deregistration of an EventLoop it was not possible to wrap an EventLoop implementation and use it with a Channel.
Modification:
- Introduce EventLoop.Unsafe which is responsible for the actual registration.
- Move validation of EventLoop / Channel combo to the EventLoop
- Add unit test that verifies that wrapping works
Result:
Be able to wrap an EventLoop and so add some extra functionality.
Motivation:
ByteBuf supports “marker indexes”. The intended use case for these is if a speculative operation (e.g. decode) is in process the user can “mark” and interface and refer to it later if the operation isn’t successful (e.g. not enough data). However this is rarely used in practice,
requires extra memory to maintain, and introduces complexity in the state management for derived/pooled buffer initialization, resizing, and other operations which may modify reader/writer indexes.
Modifications:
Remove support for marking and adjust testcases / code.
Result:
Fixes https://github.com/netty/netty/issues/8535.
