This module wraps Feign's http requests in a Reactive Streams
Publisher, enabling the use of Reactive Stream Publisher return types. Supported Reactive Streams implementations are:
- Reactor (
MonoandFlux) - ReactiveX (RxJava) (
Flowableonly)
To use these wrappers, add the feign-reactive-wrappers module, and your desired reactive-streams
implementation to your classpath. Then configure Feign to use the reactive streams wrappers.
public interface GitHubReactor {
@RequestLine("GET /repos/{owner}/{repo}/contributors")
Flux<Contributor> contributors(@Param("owner") String owner, @Param("repo") String repo);
class Contributor {
String login;
public Contributor(String login) {
this.login = login;
}
}
}
public class ExampleReactor {
public static void main(String args[]) {
GitHubReactor gitHub = ReactorFeign.builder()
.target(GitHubReactor.class, "https://api.github.com");
List<Contributor> contributors = gitHub.contributors("OpenFeign", "feign")
.collect(Collectors.toList())
.block();
}
}
public interface GitHubReactiveX {
@RequestLine("GET /repos/{owner}/{repo}/contributors")
Flowable<Contributor> contributors(@Param("owner") String owner, @Param("repo") String repo);
class Contributor {
String login;
public Contributor(String login) {
this.login = login;
}
}
}
public class ExampleRxJava2 {
public static void main(String args[]) {
GitHubReactiveX gitHub = RxJavaFeign.builder()
.target(GitHub.class, "https://api.github.com");
List<Contributor> contributors = gitHub.contributors("OpenFeign", "feign")
.collect(Collectors.toList())
.block();
}
}These wrappers are not reactive all the way down, given that Feign generated requests are
synchronous. Requests still block, but execution is controlled by the Publisher and their
related Scheduler. While this may not be ideal in terms of a fully reactive application, providing these
wrappers provide an intermediate upgrade path for Feign.
Methods that return java.util.streams Types are not supported. Responses are read fully,
the wrapped in the appropriate reactive wrappers.
Due to the Synchronous nature of Feign requests, methods that return Iterable types must specify the collection
in the Publisher. For Reactor types, this limits the use of Flux as a response type. If you
want to use Flux, you will need to manually convert the Mono or Iterable response types into
Flux using the fromIterable method.
public interface GitHub {
@RequestLine("GET /repos/{owner}/{repo}/contributors")
Mono<List<Contributor>> contributors(@Param("owner") String owner, @Param("repo") String repo);
class Contributor {
String login;
public Contributor(String login) {
this.login = login;
}
}
}
public class ExampleApplication {
public static void main(String[] args) {
GitHub gitHub = ReactorFeign.builder()
.target(GitHub.class, "https://api.github.com");
Mono<List<Contributor>> contributors = gitHub.contributors("OpenFeign", "feign");
Flux<Contributor> contributorFlux = Flux.fromIterable(contributors.block());
}
}