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. Add session count threshold as am extra pre-condition.
2. Check pre-conditions for expiration checks on every request.
Effectively an upper bound on how many sessions can be created before
expiration checks are performed.
Issue: SPR-17020
This commit restricts the support of `"Content-Range"` when returning
`Resource` instances from Controllers - now only "HTTP 200 OK" responses
will be considered, as Controllers might want to handle content range
themselves.
Issue: SPR-16921
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.
Brian Clozel
Juergen Hoeller
Rossen Stoyanchev
Stephane Nicoll
Guilherme Alan Ritter
xiexed
zilong6
Arjen Poutsma
stsypanov
Sam Brannen
Sebastien Deleuze
Violeta Georgieva