69 lines
3.2 KiB
Plaintext
69 lines
3.2 KiB
Plaintext
[[spring-web-reactive]]
|
|
= Web on Reactive Stack
|
|
:doc-root: https://docs.spring.io
|
|
:api-spring-framework: {doc-root}/spring-framework/docs/{spring-version}/javadoc-api/org/springframework
|
|
:toc: left
|
|
:toclevels: 4
|
|
:docinfo1:
|
|
|
|
This part of the documentation covers support for reactive stack, web applications built on a
|
|
http://www.reactive-streams.org/[Reactive Streams] API to run on non-blocking
|
|
servers such as Netty, Undertow, and Servlet 3.1+ containers. Individual chapters cover
|
|
the <<webflux-module,Spring WebFlux>> framework,
|
|
the reactive <<webflux-client,WebClient>>, support for <<webflux-test>>,
|
|
and <<webflux-reactive-libraries>>. For Servlet stack, web applications, please see
|
|
<<web.adoc#spring-web,Web on Servlet Stack>>.
|
|
|
|
include::web/webflux.adoc[leveloffset=+1]
|
|
|
|
include::web/webflux-webclient.adoc[leveloffset=+1]
|
|
|
|
|
|
[[webflux-test]]
|
|
== Testing
|
|
|
|
The `spring-test` module provides mock implementations of `ServerHttpRequest`,
|
|
`ServerHttpResponse`, and `ServerWebExchange`.
|
|
See <<testing.adoc#mock-objects-web-reactive,Spring Web Reactive>> mock objects.
|
|
|
|
The <<testing.adoc#webtestclient,WebTestClient>> builds on these mock request and
|
|
response objects to provide support for testing WebFlux applications without and HTTP
|
|
server. The `WebTestClient` can be used for end-to-end integration tests too.
|
|
|
|
|
|
[[webflux-reactive-libraries]]
|
|
== Reactive Libraries
|
|
|
|
Reactor is a required dependency for the `spring-webflux` module and is used internally
|
|
for composing logic and for Reactive Streams support. An easy rule to remember is that
|
|
WebFlux APIs return `Flux` or `Mono` -- since that's what's used internally, and
|
|
leniently accept any Reactive Streams `Publisher` implementation.
|
|
|
|
The use of `Flux` and `Mono` helps to express cardinality -- e.g.
|
|
whether a single or multiple async values are expected. This is important for API design
|
|
but also essential in some cases, e.g. when encoding an HTTP message.
|
|
|
|
For annotated controllers, WebFlux adapts transparently to the reactive library in use
|
|
with proper translation of cardinality. This is done with the help of the
|
|
{api-spring-framework}/core/ReactiveAdapterRegistry.html[ReactiveAdapterRegistry] from
|
|
`spring-core` which provides pluggable support for reactive and async types. The registry
|
|
has built-in support for RxJava and `CompletableFuture` but others can be registered.
|
|
|
|
For functional endpoints, the `WebClient`, and other functional APIs, the general rule
|
|
of thumb for WebFlux APIs applies:
|
|
|
|
* `Flux` or `Mono` as return values -- use them to compose logic or pass to any Reactive
|
|
Streams library (both are `Publisher` implementations).
|
|
* Reactive Streams `Publisher` for input -- if a `Publisher` from another reactive library
|
|
is provided it can only be treated as a stream with unknown semantics (0..N). If the
|
|
semantics are known -- e.g. `io.reactivex.Single`, you can use `Mono.from(Publisher)` and
|
|
pass that in instead of the raw `Publisher`.
|
|
|
|
[NOTE]
|
|
====
|
|
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 -- e.g.
|
|
`"application/json+stream"`, values are written and flushed individually; otherwise
|
|
values are buffered into a list and rendered as a JSON array.
|
|
====
|