Leverage https://github.com/jetty-project/jetty-reactive-httpclient
to add support for Jetty in WebClient via JettyClientHttpConnector.
Implemented with buffer copy instead of optimized buffer wrapping
because the latter hangs since Callback#succeeded doesn't allow
releasing the buffer and requesting more data at different times
(required for Mono<DataBuffer> for example).
See https://github.com/eclipse/jetty.project/issues/2429.
Issue: SPR-15092
Prior to this commit, resolving an argument for a WebFlux controller
that's missing from the request and not required by the handler would
throw a NullPointerException in some cases.
This involves the conversion of the parameter (a `String` parameter type
might not trigger this behavior) and sending a `null` within a reactive
stream, which is illegal per the RS spec.
We now rely on a `Mono.justOrEmpty()` to handle those specific cases.
Issue: SPR-17050
Prior to this commit, `WebClient` would throw `IllegalArgumentException`
when receiving an HTTP response with an unknown HTTP status code.
This commit is a follow up of SPR-16748 (supporting non-standard HTTP
status codes on the reactive `ClientHttpResponse`), and is mirroring
SPR-15978 (supporting non-standard HTTP status codes in `RestTemplate`).
With this change, `WebClient` now tolerates unknown status codes in some
cases, while not offering that choice as a first class citizen:
`HttpStatus` is still the preferred way to deal with HTTP status codes.
Here's how `WebClient` will behave when fetching the full response:
```
// Given a remote endpoint returning a "123" HTTP status code
Mono<ClientResponse> result = this.webClient.get()
.uri("/status/123")
.exchange();
// will still throw an IllegalArgumentException
HttpStatus status = result.block().statusCode();
// is safe and will return 123
int statusCode = result.block().rawStatusCode();
```
Resolving directly the response body with `retrieve()` is different.
```
// will send an error signal with a UnknownHttpStatusCodeException
Mono<String> result = this.webClient.get()
.uri("/status/123")
.retrieve()
.bodyToMono(String.class);
```
In general, `WebClient` will provide high-level support
for well-known HTTP status codes, like error handling with
`WebClient.ResponseSpec#onStatus`.
For such support with unknown status codes, it is better to rely
on lower level constructs such as `ExchangeFilterFunction`.
Issue: SPR-16819
1. Use special category prefix "spring-web.reactivestreams" for logging
of reactive streams signals in spring-web, since those are quite
verbose would fill the logs at TRACE.
2. Add and use loggers in request and websocket session implementations
separate from reactive streams bridge for regular TRACE logging.
3. Improve log messages and add where missing (e.g. for Reactor)
Issue: SPR-16898
Hiding it (at AbstractServerHttpRequest) complicates matters since
requests are often mutated and decorated, plus it's also possible to
implement the interface directly (we've one, albeit corner case).
Issue: SPR-16966
1. Eliminate WebSocketClientSupport base class whose main value was
to provide logging but those methods get in the way of inserting a
log prefix.
2. Remove checks and synchronization in lifecycle methods of Jetty
client since underlying Jetty client already has that.
This commit introduces RouterFunctions.Builder, a new way to build
router functions that does not require static imports, thus being more
discoverable and convenient.
Issue: SPR-16953
Polish a few issue identified when adding checkstyle to the
build. Although checkstyle is not enforcing rules on tests,
these are a few minor changes that are still worth making.
Issue: SPR-16968
Reorganize imports to ensure consistent ordering. This commit also
expands any `.*` static imports in favor of using fully-qualified
method references.
Issue: SPR-16968
Update all classes so that inner classes are always last. Also
ensure that utility classes are always final and have a private
constructor and make exceptions final whenever possible.
Issue: SPR-16968
In SPR-16892, the `EncoderHttpMessageWriter` has been improved to write
`"Content-Length"` HTTP response headers if the response body is of type
`Mono` (i.e. the actual content length is easily accessible without
buffering a possibly large response body). That change was relying on
the fact that the server side is using a `ChannelSendOperator` to delay
the writing of the body until the first signal is received.
This strategy is not effective on the client side, since no such channel
operator is used for `WebClient`. This commit improves
`EncoderHttpMessageWriter` and delays, for `Mono` HTTP message bodies
only, the writing of the body so that we can write the
`"Content-Length"` header information once we've got the body resolved.
Issue: SPR-16949
