This commit harmonizes the `HeadersAdapter` implementations across all
supported servers with regards to the `get(Object key)` contract; some
server implementations are not sticking to a `Map`-like contract and
return empty `List` instead of `null` when a header is not present.
This also fixes the `size()` implementations to reflect the number of
header keys, as some implementations consider multiple values for the
same header as different entries.
Issue: SPR-17396
This commit adds special processing of some HTTP response headers in
Jetty and Tomcat; they both consider some headers like "Content-Length"
as specific and require explicit calls on the `HttpServletResponse`
itself on top of setting the HTTP response header.
Issue: SPR-17250
This commit avoids copying HTTP headers when mutating an HTTP request.
Instead, we're now unwrapping the `ReadOnlyHttpHeaders` (which is most
likely backed by the native request headers).
Issue: SPR-17250
Several benchmarks underlined a few hotspots for CPU and GC pressure in
the Spring Framework codebase:
1. `org.springframework.util.MimeType.<init>(String, String, Map)`
2. `org.springframework.util.LinkedCaseInsensitiveMap.convertKey(String)`
Both are linked with HTTP request headers parsing and response headers
writin during the exchange processing phase.
1) is linked to repeated calls to `HttpHeaders.getContentType`
within a single request handling. The media type parsing operation
is expensive and the result doesn't change between calls, since
the request headers are immutable at that point.
This commit improves this by caching the parsed `MediaType` for the
`"Content-Type"` request header in the `ReadOnlyHttpHeaders` class.
This change is available for both Spring MVC and Spring WebFlux.
2) is linked to insertions/lookups in the `LinkedCaseInsensitiveMap`,
which is the data structure behind `HttpHeaders`.
Those operations are creating a lot of garbage (including a lot of
`String` created by `toLowerCase`). We could choose a more efficient
data structure for storing HTTP headers data.
As a first step, this commit is focusing on Spring WebFlux and
introduces `MultiValueMap` implementations mapped by native HTTP headers
for the following servers: Tomcat, Jetty, Netty and Undertow.
Such implementations avoid unnecessary copying of the headers
and leverages as much as possible optimized operations provided by the
native implementations.
This change has a few consequences:
* `HttpHeaders` can now wrap a `MultiValueMap` directly
* The default constructor of `HttpHeaders` is still backed by a
`LinkedCaseInsensitiveMap`
* The HTTP request headers for the websocket HTTP handshake now need to
be cloned, because native headers are likely to be pooled/recycled by
the server implementation, hence gone when the initial HTTP exchange is
done
Issue: SPR-17250
In order to be able to leverage WebFlux configuration in a functional
way, WebHttpHandlerBuilder and RouterFunctionMapping should leverage
new ObjectProvider capabilities to get a sorted list of beans by type
instead of using autowired containers.
Issue: SPR-17327
1. Helper method to eliminate duplication in formatting (de-)serialized
values for logging introduced with prior commit #e62298.
2. Helper method for TRACE vs DEBUG logging with different details.
Issue: SPR-17254
At DEBUG show up to 100 chars, at TRACE show full formatted value.
Note that the formatValue helper method is duplicated a number of times
in this commit. A utility method will likely be added in spring-core
through an extra commit.
Issue: SPR-17254
1. Rename globalResources to useGlobalResources.
2. Use of global resources is mutually exlusive with explicit config.
3. Allow Consumer<HttpResources> to configure global resources.
4. Allow ConnectionProvider + LoopResources Supplier to customize
creation and initialization.
5. Do not manage externally provided ConnectionProvider + LoopResources
instances.
Issue: SPR-17243
This commit optimizes Flux <-> Mono conversions in our codebase by
avoiding to hide that conversion from Reactor.
This tries to keep conversions sequentially so that they can be detected
by Reactor and optimized. In Spring WebFlux, this means keeping the
conversions at the edges of a method implementation (right when getting
an input parameter, and before returning it as a result). If those
conversions are made between other operators, Reactor might not be able
to detect those conversions and optimize them.
Issue: SPR-17203
Prior to this commit, an bug introduced in SPR-16949 prevented
`Mono.empty` bodies from being written to the response.
This commit ensures that empty bodies still trigger the writing to the
response and does not hang the processing of the exchange.
Issue: SPR-17220
This commit represents a best effort attempt at fixing remaining
"a" vs. "an" grammatical errors related links specified via a fully
qualified class name.
Issue: SPR-17208
When used as global Netty resources, ReactorResourceFactory creates and
sets those resources on Reactor's HttpResources directly.
When that ReactorResourceFactory bean is destroyed, those resources are
disposed but HttpResources still holds a reference to those and may try
to use them again.
This commit uses HttpResources to clear those resources and its
references to it, when the ReactorResourceFactory is treating those as
global.
Issue: SPR-17199
JettyResourceFactory, similar to ReactorResourceFactory, allows
to share resources (Executor, ByteBufferPool, Scheduler) between
Jetty clients and servers.
Issue: SPR-17179
Prior to this commit, when using the `SimpleClientHttpRequestFactory`
as a driver for `RestTemplate`, the HTTP response body would only be
drained if there was an attempt to read it in the first place.
This commit ensures that, even if there's no attempt at reading the
response body, it is properly drained when the response is closed to
make sure that the connection is released in a proper state and can be
put back in the connection pool for reuse.
Issue: SPR-17181
When dealing with `Optional` values in a Controller handler (for
example, values coming from a Spring Data repository), developers might
reuse this code snippet quite often:
```
@GetMapping("/user")
public ResponseEntity<Optional<User>> fetchUser() {
Optional<User> user = //...
return user.map(ResponseEntity::ok).orElse(notFound().build());
}
```
This commit adds a new static method on `ResponseEntity` for that,
simplifying the previous snippet with `return ResponseEntity.of(user);`
Note that in case more specific HTTP response headers are required by
the application, developers should use other static methods to
explicitly tell which headers should be used in each case.
Issue: SPR-17187
Rename "Builder" sub-section to "Configuration" and move it in the
beginning before all others since it explains how to create a client
in the first place.
Update content on Reactor Netty connector based on the API in 0.8 and
specifically address Reactor Netty resources and lifecycle.
Issue: SPR-16963
