Support for Spring 6 HTTP interface (#5370)

Motivation:

The Spring Framework 6 supports defining declarative HTTP services using Java interfaces like [Feign](https://www.baeldung.com/spring-boot-feignclient-vs-webclient).
That could be an alternative choice for Spring users instead of Retrofit.

Modifications:

- Add `spring6` module to provide `ArmeriaHttpExchangeAdapter`.
- `ArmeriaClientHttpRequest` and `ArmeriaClientHttpRequest` are moved to Spring 6 module from the WebFlux module.
  - The WebFlux module now depends on Spring 6 to share the files.
- `ClientRequest` and `ClientResponse` in Spring 6 are used as a bridge to encode an object into `HttpData` and vice versa.

Result:

You can now create Spring 6 HTTP interface with Armeria `WebClient`. 
```java
import com.linecorp.armeria.client.WebClient;
import org.springframework.web.service.invoker.HttpServiceProxyFactory;

WebClient webClient = ...;
ArmeriaHttpExchangeAdapter adapter = ArmeriaHttpExchangeAdapter.of(webClient);
MyService service =
  HttpServiceProxyFactory.builderFor(adapter)
                         .build()
                         .createClient(MyService.class);
```

dependencies.toml

@@ -1191,9 +1191,18 @@ module = "org.slf4j:slf4j-api"
 version.ref = "slf4j2"
 javadocs = "https://www.javadoc.io/doc/org.slf4j/slf4j-api/2.0.7/"
 
+[libraries.spring6-context]
+module = "org.springframework:spring-context"
+version.ref = "spring6"
+[libraries.spring6-test]
+module = "org.springframework:spring-test"
+version.ref = "spring6"
 [libraries.spring6-web]
 module = "org.springframework:spring-web"
 version.ref = "spring6"
+[libraries.spring6-webflux]
+module = "org.springframework:spring-webflux"
+version.ref = "spring6"
 
 [libraries.spring-boot2-actuator-autoconfigure]
 module = "org.springframework.boot:spring-boot-actuator-autoconfigure"

settings.gradle

@@ -156,6 +156,7 @@ includeWithFlags ':spring:boot3-autoconfigure',          'java17', 'publish', 'r
 includeWithFlags ':spring:boot3-starter',                'java17', 'publish', 'relocate'
 includeWithFlags ':spring:boot3-webflux-autoconfigure',  'java17', 'publish', 'relocate'
 includeWithFlags ':spring:boot3-webflux-starter',        'java17', 'publish', 'relocate'
+includeWithFlags ':spring:spring6',                      'java17', 'publish', 'relocate'
 
 includeWithFlags ':dropwizard1',                         'java', 'publish', 'relocate', 'no_aggregation'
 includeWithFlags ':dropwizard2',                         'java', 'publish', 'relocate'

spring/boot2-webflux-autoconfigure/build.gradle

@@ -64,9 +64,20 @@ task copyBoot3Sources(type: Copy) {
     into "${project.ext.genSrcDir}/main/java"
 }
 
+task copySpring6Sources(type: Copy) {
+    from("${rootProject.projectDir}/spring/spring6/src/main/java") {
+        include '**/ArmeriaClientHttpRequest.java'
+        include '**/ArmeriaClientHttpResponse.java'
+        include '**/DataBufferFactoryWrapper.java'
+    }
+
+    into "${project.ext.genSrcDir}/main/java"
+}
+
 // Copy the main and test sources from ':spring:boot3-webflux-autoconfigure'.
 task generateSources(type: Copy) {
     dependsOn(tasks.copyBoot3Sources)
+    dependsOn(tasks.copySpring6Sources)
     from("${"${rootProject.projectDir}/spring/boot3-webflux-autoconfigure"}/src") {
         exclude '**/AbstractServerHttpResponseVersionSpecific.java'
         exclude '**/AbstractServerHttpRequestVersionSpecific.java'

spring/boot3-webflux-autoconfigure/build.gradle

@@ -10,6 +10,7 @@ dependencies {
     // To let a user choose between thrift and thrift0.9.
     compileOnly project(':thrift0.18')
     implementation project(':logback')
+    implementation project(':spring:spring6')
 
     api libs.spring.boot3.starter.webflux
     api libs.jakarta.inject

spring/boot3-webflux-autoconfigure/src/main/java/com/linecorp/armeria/spring/web/reactive/ArmeriaClientAutoConfiguration.java

@@ -28,6 +28,8 @@
 import org.springframework.web.reactive.function.client.WebClient;
 import org.springframework.web.reactive.function.client.WebClient.Builder;
 
+import com.linecorp.armeria.spring.internal.common.DataBufferFactoryWrapper;
+
 /**
  * An auto-configuration for Armeria-based {@link WebClient}.
  */

spring/boot3-webflux-autoconfigure/src/main/java/com/linecorp/armeria/spring/web/reactive/ArmeriaClientHttpConnector.java

@@ -36,6 +36,9 @@
 import com.linecorp.armeria.client.WebClient;
 import com.linecorp.armeria.client.WebClientBuilder;
 import com.linecorp.armeria.common.HttpResponse;
+import com.linecorp.armeria.spring.internal.client.ArmeriaClientHttpRequest;
+import com.linecorp.armeria.spring.internal.client.ArmeriaClientHttpResponse;
+import com.linecorp.armeria.spring.internal.common.DataBufferFactoryWrapper;
 
 import reactor.core.publisher.Mono;
 
@@ -105,7 +108,7 @@ private ArmeriaClientHttpRequest createRequest(HttpMethod method, URI uri) {
         checkArgument(!Strings.isNullOrEmpty(path), "path is undefined: %s", uri);
         final String pathAndQuery = Strings.isNullOrEmpty(query) ? path : path + '?' + query;
 
-        return new ArmeriaClientHttpRequest(webClient, method, pathAndQuery, uri, factoryWrapper);
+        return new ArmeriaClientHttpRequest(webClient, method, pathAndQuery, uri, factoryWrapper, null);
     }
 
     private CompletableFuture<ArmeriaClientHttpResponse> createResponse(HttpResponse response) {

spring/boot3-webflux-autoconfigure/src/main/java/com/linecorp/armeria/spring/web/reactive/ArmeriaHttpHandlerAdapter.java

@@ -29,6 +29,7 @@
 import com.linecorp.armeria.common.MediaType;
 import com.linecorp.armeria.common.annotation.Nullable;
 import com.linecorp.armeria.server.ServiceRequestContext;
+import com.linecorp.armeria.spring.internal.common.DataBufferFactoryWrapper;
 
 import reactor.core.publisher.Mono;
 

spring/boot3-webflux-autoconfigure/src/main/java/com/linecorp/armeria/spring/web/reactive/ArmeriaReactiveWebServerFactory.java

@@ -69,6 +69,7 @@
 import com.linecorp.armeria.spring.ArmeriaSettings;
 import com.linecorp.armeria.spring.InternalServices;
 import com.linecorp.armeria.spring.MetricCollectingServiceConfigurator;
+import com.linecorp.armeria.spring.internal.common.DataBufferFactoryWrapper;
 
 import io.micrometer.core.instrument.MeterRegistry;
 import io.netty.handler.ssl.ClientAuth;

spring/boot3-webflux-autoconfigure/src/main/java/com/linecorp/armeria/spring/web/reactive/ArmeriaServerHttpRequest.java

@@ -43,6 +43,7 @@
 import com.linecorp.armeria.common.RequestTarget;
 import com.linecorp.armeria.common.annotation.Nullable;
 import com.linecorp.armeria.server.ServiceRequestContext;
+import com.linecorp.armeria.spring.internal.common.DataBufferFactoryWrapper;
 
 import io.netty.handler.codec.http.cookie.ServerCookieDecoder;
 import reactor.core.publisher.Flux;

spring/boot3-webflux-autoconfigure/src/main/java/com/linecorp/armeria/spring/web/reactive/ArmeriaServerHttpResponse.java

@@ -45,6 +45,7 @@
 import com.linecorp.armeria.common.stream.AbortedStreamException;
 import com.linecorp.armeria.common.stream.CancelledSubscriptionException;
 import com.linecorp.armeria.server.ServiceRequestContext;
+import com.linecorp.armeria.spring.internal.common.DataBufferFactoryWrapper;
 
 import reactor.core.publisher.Flux;
 import reactor.core.publisher.Mono;

spring/boot3-webflux-autoconfigure/src/main/java/com/linecorp/armeria/spring/web/reactive/DataBufferFactoryWrapperConfiguration.java

@@ -22,6 +22,8 @@
 import org.springframework.context.annotation.Configuration;
 import org.springframework.core.io.buffer.DataBufferFactory;
 
+import com.linecorp.armeria.spring.internal.common.DataBufferFactoryWrapper;
+
 /**
  * A configuration class which creates an {@link DataBufferFactoryWrapper}.
  */

spring/boot3-webflux-autoconfigure/src/test/java/com/linecorp/armeria/spring/web/reactive/ArmeriaClientHttpRequestTest.java

@@ -17,16 +17,14 @@
 
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.awaitility.Awaitility.await;
-import static org.mockito.ArgumentMatchers.any;
-import static org.mockito.Mockito.mock;
-import static org.mockito.Mockito.when;
 
 import java.net.URI;
 import java.util.List;
 import java.util.Map.Entry;
 
 import org.junit.jupiter.api.BeforeAll;
 import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.RegisterExtension;
 import org.springframework.core.io.buffer.DataBuffer;
 import org.springframework.http.HttpCookie;
 import org.springframework.http.HttpMethod;
@@ -38,6 +36,11 @@
 import com.linecorp.armeria.common.HttpResponse;
 import com.linecorp.armeria.common.HttpStatus;
 import com.linecorp.armeria.common.RequestHeaders;
+import com.linecorp.armeria.server.Route;
+import com.linecorp.armeria.server.ServerBuilder;
+import com.linecorp.armeria.spring.internal.client.ArmeriaClientHttpRequest;
+import com.linecorp.armeria.spring.internal.common.DataBufferFactoryWrapper;
+import com.linecorp.armeria.testing.junit5.server.ServerExtension;
 
 import reactor.core.publisher.Flux;
 import reactor.core.publisher.Mono;
@@ -47,17 +50,28 @@ class ArmeriaClientHttpRequestTest {
 
     private static final String TEST_PATH_AND_QUERY = "/index.html?q=1";
 
+    @RegisterExtension
+    static final ServerExtension server = new ServerExtension() {
+        @Override
+        protected void configure(ServerBuilder sb) {
+            sb.service(Route.ofCatchAll(), (ctx, req) -> HttpResponse.of(HttpStatus.OK));
+        }
+    };
     static WebClient webClient;
 
     @BeforeAll
     public static void beforeClass() {
-        webClient = mock(WebClient.class);
-        when(webClient.execute((HttpRequest) any())).thenReturn(HttpResponse.of(HttpStatus.OK));
+        webClient = WebClient.builder()
+                .decorator((delegate, ctx, req) -> {
+                    return HttpResponse.of(HttpStatus.OK);
+                })
+                .build();
     }
 
     private static ArmeriaClientHttpRequest request() {
         return new ArmeriaClientHttpRequest(webClient, HttpMethod.GET, TEST_PATH_AND_QUERY,
-                                            URI.create("http://localhost"), DataBufferFactoryWrapper.DEFAULT);
+                                            URI.create("http://localhost"), DataBufferFactoryWrapper.DEFAULT,
+                                            null);
     }
 
     @Test

spring/boot3-webflux-autoconfigure/src/test/java/com/linecorp/armeria/spring/web/reactive/ArmeriaClientHttpResponseTest.java

@@ -35,6 +35,8 @@
 import com.linecorp.armeria.common.HttpStatus;
 import com.linecorp.armeria.common.ResponseHeaders;
 import com.linecorp.armeria.common.stream.CancelledSubscriptionException;
+import com.linecorp.armeria.spring.internal.client.ArmeriaClientHttpResponse;
+import com.linecorp.armeria.spring.internal.common.DataBufferFactoryWrapper;
 
 import io.netty.util.concurrent.ImmediateEventExecutor;
 import reactor.core.publisher.Flux;

spring/boot3-webflux-autoconfigure/src/test/java/com/linecorp/armeria/spring/web/reactive/ArmeriaServerHttpRequestTest.java

@@ -36,6 +36,7 @@
 import com.linecorp.armeria.common.stream.CancelledSubscriptionException;
 import com.linecorp.armeria.common.util.EventLoopGroups;
 import com.linecorp.armeria.server.ServiceRequestContext;
+import com.linecorp.armeria.spring.internal.common.DataBufferFactoryWrapper;
 
 import reactor.core.publisher.Flux;
 import reactor.test.StepVerifier;

spring/boot3-webflux-autoconfigure/src/test/java/com/linecorp/armeria/spring/web/reactive/ArmeriaServerHttpResponseTest.java

@@ -46,6 +46,7 @@
 import com.linecorp.armeria.common.ResponseHeaders;
 import com.linecorp.armeria.common.stream.CancelledSubscriptionException;
 import com.linecorp.armeria.server.ServiceRequestContext;
+import com.linecorp.armeria.spring.internal.common.DataBufferFactoryWrapper;
 
 import io.netty.buffer.PooledByteBufAllocator;
 import reactor.core.publisher.Flux;

spring/boot3-webflux-autoconfigure/src/test/java/com/linecorp/armeria/spring/web/reactive/DataBufferFactoryWrapperTest.java

@@ -27,6 +27,7 @@
 import org.springframework.core.io.buffer.NettyDataBufferFactory;
 
 import com.linecorp.armeria.common.HttpData;
+import com.linecorp.armeria.spring.internal.common.DataBufferFactoryWrapper;
 
 import io.netty.buffer.ByteBuf;
 import io.netty.buffer.ByteBufUtil;

spring/spring6/build.gradle.kts

@@ -0,0 +1,5 @@
+dependencies {
+    api(libs.spring6.webflux)
+    testImplementation(libs.spring6.context)
+    testImplementation(libs.spring6.test)
+}