74 lines
3.5 KiB
Plaintext
74 lines
3.5 KiB
Plaintext
[[spring-web-reactive]]
|
|
= Web on Reactive Stack
|
|
|
|
This part of the documentation covers support for reactive-stack web applications built
|
|
on a https://www.reactive-streams.org/[Reactive Streams] API to run on non-blocking
|
|
servers, such as Netty, Undertow, and Servlet containers. Individual chapters cover
|
|
the xref:web/webflux.adoc#webflux[Spring WebFlux] framework,
|
|
the reactive xref:web/webflux-webclient.adoc[`WebClient`], support for xref:web-reactive.adoc#webflux-test[testing],
|
|
and xref:web-reactive.adoc#webflux-reactive-libraries[reactive libraries]. For Servlet-stack web applications,
|
|
see xref:web.adoc[Web on Servlet Stack].
|
|
|
|
|
|
|
|
|
|
[[webflux-http-interface-client]]
|
|
== HTTP Interface Client
|
|
|
|
The Spring Frameworks lets you define an HTTP service as a Java interface with HTTP
|
|
exchange methods. You can then generate a proxy that implements this interface and
|
|
performs the exchanges. This helps to simplify HTTP remote access and provides additional
|
|
flexibility for to choose an API style such as synchronous or reactive.
|
|
|
|
See xref:integration/rest-clients.adoc#rest-http-interface[REST Endpoints] for details.
|
|
|
|
|
|
|
|
|
|
|
|
[[webflux-test]]
|
|
== Testing
|
|
[.small]#xref:web/webmvc-test.adoc[Same in Spring MVC]#
|
|
|
|
The `spring-test` module provides mock implementations of `ServerHttpRequest`,
|
|
`ServerHttpResponse`, and `ServerWebExchange`.
|
|
See xref:testing/unit.adoc#mock-objects-web-reactive[Spring Web Reactive] for a
|
|
discussion of mock objects.
|
|
|
|
xref:testing/webtestclient.adoc[`WebTestClient`] builds on these mock request and
|
|
response objects to provide support for testing WebFlux applications without an HTTP
|
|
server. You can use the `WebTestClient` for end-to-end integration tests, too.
|
|
|
|
|
|
|
|
|
|
[[webflux-reactive-libraries]]
|
|
== Reactive Libraries
|
|
|
|
`spring-webflux` depends on `reactor-core` and uses it internally to compose asynchronous
|
|
logic and to provide Reactive Streams support. Generally, WebFlux APIs return `Flux` or
|
|
`Mono` (since those are used internally) and leniently accept any Reactive Streams
|
|
`Publisher` implementation as input. The use of `Flux` versus `Mono` is important, because
|
|
it helps to express cardinality -- for example, whether a single or multiple asynchronous
|
|
values are expected, and that can be essential for making decisions (for example, when
|
|
encoding or decoding HTTP messages).
|
|
|
|
For annotated controllers, WebFlux transparently adapts to the reactive library chosen by
|
|
the application. This is done with the help of the
|
|
{api-spring-framework}/core/ReactiveAdapterRegistry.html[`ReactiveAdapterRegistry`], which
|
|
provides pluggable support for reactive library and other asynchronous types. The registry
|
|
has built-in support for RxJava 3, Kotlin coroutines and SmallRye Mutiny, but you can
|
|
register others, too.
|
|
|
|
For functional APIs (such as <<webflux-fn>>, the `WebClient`, and others), the general rules
|
|
for WebFlux APIs apply -- `Flux` and `Mono` as return values and a Reactive Streams
|
|
`Publisher` as input. When a `Publisher`, whether custom or from another reactive library,
|
|
is provided, it can be treated only as a stream with unknown semantics (0..N). If, however,
|
|
the semantics are known, you can wrap it with `Flux` or `Mono.from(Publisher)` instead
|
|
of passing the raw `Publisher`.
|
|
|
|
For example, given a `Publisher` that is not a `Mono`, the Jackson JSON message writer
|
|
expects multiple values. If the media type implies an infinite stream (for example,
|
|
`application/json+stream`), values are written and flushed individually. Otherwise,
|
|
values are buffered into a list and rendered as a JSON array.
|