Support multi-view rendering

See gh-33162

spring-webflux/src/test/java/org/springframework/web/reactive/result/view/FragmentResolutionResultHandlerTests.java

@@ -0,0 +1,132 @@
+/*
+ * Copyright 2002-2024 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.web.reactive.result.view;
+
+import java.time.Duration;
+import java.util.List;
+import java.util.Locale;
+import java.util.Map;
+import java.util.stream.Stream;
+
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
+import reactor.core.publisher.Flux;
+import reactor.core.publisher.Mono;
+import reactor.core.scheduler.Schedulers;
+
+import org.springframework.context.annotation.AnnotationConfigApplicationContext;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.context.support.ResourceBundleMessageSource;
+import org.springframework.http.MediaType;
+import org.springframework.web.reactive.BindingContext;
+import org.springframework.web.reactive.HandlerResult;
+import org.springframework.web.reactive.accept.HeaderContentTypeResolver;
+import org.springframework.web.reactive.accept.RequestedContentTypeResolver;
+import org.springframework.web.reactive.result.view.script.ScriptTemplateConfigurer;
+import org.springframework.web.reactive.result.view.script.ScriptTemplateViewResolver;
+import org.springframework.web.testfixture.http.server.reactive.MockServerHttpRequest;
+import org.springframework.web.testfixture.server.MockServerWebExchange;
+
+import static org.assertj.core.api.AssertionsForClassTypes.assertThat;
+import static org.junit.jupiter.api.Named.named;
+import static org.springframework.web.testfixture.method.ResolvableMethod.on;
+
+/**
+ * Tests for multi-view rendering through {@link ViewResolutionResultHandler}.
+ *
+ * @author Rossen Stoyanchev
+ */
+public class FragmentResolutionResultHandlerTests {
+
+		static Stream<Arguments> arguments() {
+			Fragment f1 = Fragment.create("fragment1", Map.of("foo", "Foo"));
+			Fragment f2 = Fragment.create("fragment2", Map.of("bar", "Bar"));
+			return Stream.of(
+					Arguments.of(named("Flux",
+							FragmentRendering.fromPublisher(Flux.just(f1, f2).subscribeOn(Schedulers.boundedElastic()))
+									.headers(headers -> headers.setContentType(MediaType.TEXT_HTML))
+									.build())),
+					Arguments.of(named("List",
+							FragmentRendering.fromCollection(List.of(f1, f2))
+									.headers(headers -> headers.setContentType(MediaType.TEXT_HTML))
+									.build()))
+			);}
+
+
+	@ParameterizedTest
+	@MethodSource("arguments")
+	void render(FragmentRendering rendering) {
+
+		Locale locale = Locale.ENGLISH;
+		MockServerHttpRequest request = MockServerHttpRequest.get("/").acceptLanguageAsLocales(locale).build();
+		MockServerWebExchange exchange = MockServerWebExchange.from(request);
+
+		HandlerResult result = new HandlerResult(
+				new Handler(), rendering, on(Handler.class).resolveReturnType(FragmentRendering.class),
+				new BindingContext());
+
+		String body = initHandler().handleResult(exchange, result)
+				.then(Mono.defer(() -> exchange.getResponse().getBodyAsString()))
+				.block(Duration.ofSeconds(60));
+
+		assertThat(body).isEqualTo("<p>Hello Foo</p><p>Hello Bar</p>");
+	}
+
+	private ViewResolutionResultHandler initHandler() {
+
+		AnnotationConfigApplicationContext context =
+				new AnnotationConfigApplicationContext(ScriptTemplatingConfiguration.class);
+
+		String prefix = "org/springframework/web/reactive/result/view/script/kotlin/";
+		ScriptTemplateViewResolver viewResolver = new ScriptTemplateViewResolver(prefix, ".kts");
+		viewResolver.setApplicationContext(context);
+
+		RequestedContentTypeResolver contentTypeResolver = new HeaderContentTypeResolver();
+		return new ViewResolutionResultHandler(List.of(viewResolver), contentTypeResolver);
+	}
+
+
+	private static class Handler {
+
+		FragmentRendering rendering() { return null; }
+
+	}
+
+
+	@Configuration
+	static class ScriptTemplatingConfiguration {
+
+		@Bean
+		public ScriptTemplateConfigurer kotlinScriptConfigurer() {
+			ScriptTemplateConfigurer configurer = new ScriptTemplateConfigurer();
+			configurer.setEngineName("kotlin");
+			configurer.setScripts("org/springframework/web/reactive/result/view/script/kotlin/render.kts");
+			configurer.setRenderFunction("render");
+			return configurer;
+		}
+
+		@Bean
+		public ResourceBundleMessageSource messageSource() {
+			ResourceBundleMessageSource messageSource = new ResourceBundleMessageSource();
+			messageSource.setBasename("org/springframework/web/reactive/result/view/script/messages");
+			return messageSource;
+		}
+	}
+
+}

spring-webflux/src/test/java/org/springframework/web/reactive/result/view/ViewResolutionResultHandlerTests.java

@@ -79,6 +79,7 @@ class ViewResolutionResultHandlerTests {
 		testSupports(on(Handler.class).resolveReturnType(Mono.class, String.class));
 
 		testSupports(on(Handler.class).resolveReturnType(Rendering.class));
+		testSupports(on(Handler.class).resolveReturnType(FragmentRendering.class));
 		testSupports(on(Handler.class).resolveReturnType(Mono.class, Rendering.class));
 
 		testSupports(on(Handler.class).resolveReturnType(View.class));
@@ -434,6 +435,8 @@ class ViewResolutionResultHandlerTests {
 		Rendering rendering() { return null; }
 		Mono<Rendering> monoRendering() { return null; }
 
+		FragmentRendering fragmentRendering() { return null; }
+
 		View view() { return null; }
 		Mono<View> monoView() { return null; }
 

spring-webflux/src/test/resources/org/springframework/web/reactive/result/view/script/kotlin/fragment1.kts

@@ -0,0 +1,3 @@
+import org.springframework.web.reactive.result.view.script.*
+
+"""<p>${i18n("hello")} $foo</p>"""

spring-webflux/src/test/resources/org/springframework/web/reactive/result/view/script/kotlin/fragment2.kts

@@ -0,0 +1,3 @@
+import org.springframework.web.reactive.result.view.script.*
+
+"""<p>${i18n("hello")} $bar</p>"""