Happy to announce that from now Java Reactive Feign client is officially backed by Playtika. All development will be conducted in Playtika fork https://github.com/Playtika/feign-reactive

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feign-reactive

Use Feign with Spring WebFlux

Overview

Implementation of Feign on Spring WebClient. Brings you the best of two worlds together : concise syntax of Feign to write client side API on fast, asynchronous and non-blocking HTTP client of Spring WebClient.

Modules

feign-reactor-core : base classes and interfaces that should allow to implement alternative reactor Feign

feign-reactor-webclient : Spring WebClient based implementation of reactor Feign

feign-reactor-cloud : Spring Cloud implementation of reactor Feign (Ribbon/Hystrix)

feign-reactor-rx2 : Rx2 compatible implementation of reactor Feign (depends on feign-reactor-webclient)

feign-reactor-jetty : experimental Reactive Jetty client based implementation of reactor Feign (doesn't depend on feign-reactor-webclient). In future will allow to write pure Rx2 version.

• have greater reactivity level then Spring WebClient. By default don't collect body to list instead starts sending request body as stream.
• starts receiving reactive response before all reactive request body has been sent
• process Flux<String> correctly in request and response body

Usage

Write Feign API as usual, but every method of interface

• may accept org.reactivestreams.Publisher as body
• must return reactor.core.publisher.Mono or reactor.core.publisher.Flux.

@Headers({ "Accept: application/json" })
public interface IcecreamServiceApi {

  @RequestLine("GET /icecream/flavors")
  Flux<Flavor> getAvailableFlavors();

  @RequestLine("GET /icecream/mixins")
  Flux<Mixin> getAvailableMixins();

  @RequestLine("POST /icecream/orders")
  @Headers("Content-Type: application/json")
  Mono<Bill> makeOrder(IceCreamOrder order);

  @RequestLine("GET /icecream/orders/{orderId}")
  Mono<IceCreamOrder> findOrder(@Param("orderId") int orderId);

  @RequestLine("POST /icecream/bills/pay")
  @Headers("Content-Type: application/json")
  Mono<Void> payBill(Publisher<Bill> bill);
}

Build the client :

/* Create instance of your API */
IcecreamServiceApi client = ReactiveFeign
    .builder()
    .target(IcecreamServiceApi.class, "http://www.icecreame.com")

/* Execute nonblocking requests */
Flux<Flavor> flavors = icecreamApi.getAvailableFlavors();
Flux<Mixin> mixins = icecreamApi.getAvailableMixins();

or cloud aware client :

 IcecreamServiceApi client = CloudReactiveFeign.<IcecreamServiceApi>builder()
    .setFallback(new TestInterface() {
        @Override
        public Mono<String> get() {
            return Mono.just("fallback");
        }
    })
    .setLoadBalancerCommand(
         LoadBalancerCommand.builder()
                 .withLoadBalancer(AbstractLoadBalancer.class.cast(getNamedLoadBalancer(serviceName)))
                 .withRetryHandler(new DefaultLoadBalancerRetryHandler(1, 1, true))
                 .build()
    )
    .target(IcecreamServiceApi.class, "http://" + serviceName);

/* Execute nonblocking requests */
Flux<Flavor> flavors = icecreamApi.getAvailableFlavors();
Flux<Mixin> mixins = icecreamApi.getAvailableMixins();

Rx2 Usage

Write Feign API as usual, but every method of interface

• may accept Flowable, Observable, Single or Maybe as body
• must return Flowable, Observable, Single or Maybe.

@Headers({"Accept: application/json"})
public interface IcecreamServiceApi {

  @RequestLine("GET /icecream/flavors")
  Flowable<Flavor> getAvailableFlavors();

  @RequestLine("GET /icecream/mixins")
  Observable<Mixin> getAvailableMixins();

  @RequestLine("POST /icecream/orders")
  @Headers("Content-Type: application/json")
  Single<Bill> makeOrder(IceCreamOrder order);

  @RequestLine("GET /icecream/orders/{orderId}")
  Maybe<IceCreamOrder> findOrder(@Param("orderId") int orderId);

  @RequestLine("POST /icecream/bills/pay")
  @Headers("Content-Type: application/json")
  Single<Long> payBill(Bill bill);

Build the client :

/* Create instance of your API */
IcecreamServiceApi client = Rx2ReactiveFeign
    .builder()
    .target(IcecreamServiceApi.class, "http://www.icecreame.com")

/* Execute nonblocking requests */
Flowable<Flavor> flavors = icecreamApi.getAvailableFlavors();
Observable<Mixin> mixins = icecreamApi.getAvailableMixins();

Maven

<repositories>
    <repository>
        <id>bintray-kptfh-feign-reactive</id>
        <name>bintray</name>
        <url>https://dl.bintray.com/kptfh/feign-reactive</url>
    </repository>
</repositories>
...
<dependencies>
    ...
    
    <dependency>
        <groupId>io.github.reactivefeign</groupId>
        <artifactId>feign-reactor-cloud</artifactId>
        <version>1.0.0</version>
    </dependency>
    
    or if you don't need cloud specific functionality
    
    <dependency>
        <groupId>io.github.reactivefeign</groupId>
        <artifactId>feign-reactor-webclient</artifactId>
        <version>1.0.0</version>
    </dependency>
    
    or if you tend to use Rx2 interfaces
    
    <dependency>
            <groupId>io.github.reactivefeign</groupId>
            <artifactId>feign-reactor-rx2</artifactId>
            <version>1.0.0</version>
        </dependency>
    ...
</dependencies>

License

Library distributed under Apache License Version 2.0.