Merge pull request #44982 from nosan

* pr/44982:
  Polish RestClientAutoConfiguration and RestClientBuilderConfigurer

Closes gh-44982

Author: mhalbritter

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/web/client/RestClientAutoConfiguration.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2024 the original author or authors.
+ * Copyright 2012-2025 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.
@@ -79,11 +79,10 @@ RestClientBuilderConfigurer restClientBuilderConfigurer(
 			ObjectProvider<ClientHttpRequestFactoryBuilder<?>> clientHttpRequestFactoryBuilder,
 			ObjectProvider<ClientHttpRequestFactorySettings> clientHttpRequestFactorySettings,
 			ObjectProvider<RestClientCustomizer> customizerProvider) {
-		RestClientBuilderConfigurer configurer = new RestClientBuilderConfigurer();
-		configurer.setRequestFactoryBuilder(clientHttpRequestFactoryBuilder.getIfAvailable());
-		configurer.setRequestFactorySettings(clientHttpRequestFactorySettings.getIfAvailable());
-		configurer.setRestClientCustomizers(customizerProvider.orderedStream().toList());
-		return configurer;
+		return new RestClientBuilderConfigurer(
+				clientHttpRequestFactoryBuilder.getIfAvailable(ClientHttpRequestFactoryBuilder::detect),
+				clientHttpRequestFactorySettings.getIfAvailable(ClientHttpRequestFactorySettings::defaults),
+				customizerProvider.orderedStream().toList());
 	}
 
 	@Bean

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/web/client/RestClientBuilderConfigurer.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2024 the original author or authors.
+ * Copyright 2012-2025 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.
@@ -16,6 +16,7 @@
 
 package org.springframework.boot.autoconfigure.web.client;
 
+import java.util.Collections;
 import java.util.List;
 
 import org.springframework.boot.http.client.ClientHttpRequestFactoryBuilder;
@@ -32,21 +33,21 @@
  */
 public class RestClientBuilderConfigurer {
 
-	private ClientHttpRequestFactoryBuilder<?> requestFactoryBuilder;
+	private final ClientHttpRequestFactoryBuilder<?> requestFactoryBuilder;
 
-	private ClientHttpRequestFactorySettings requestFactorySettings;
+	private final ClientHttpRequestFactorySettings requestFactorySettings;
 
-	private List<RestClientCustomizer> customizers;
+	private final List<RestClientCustomizer> customizers;
 
-	void setRequestFactoryBuilder(ClientHttpRequestFactoryBuilder<?> requestFactoryBuilder) {
-		this.requestFactoryBuilder = requestFactoryBuilder;
+	public RestClientBuilderConfigurer() {
+		this(ClientHttpRequestFactoryBuilder.detect(), ClientHttpRequestFactorySettings.defaults(),
+				Collections.emptyList());
 	}
 
-	void setRequestFactorySettings(ClientHttpRequestFactorySettings requestFactorySettings) {
+	RestClientBuilderConfigurer(ClientHttpRequestFactoryBuilder<?> requestFactoryBuilder,
+			ClientHttpRequestFactorySettings requestFactorySettings, List<RestClientCustomizer> customizers) {
+		this.requestFactoryBuilder = requestFactoryBuilder;
 		this.requestFactorySettings = requestFactorySettings;
-	}
-
-	void setRestClientCustomizers(List<RestClientCustomizer> customizers) {
 		this.customizers = customizers;
 	}
 
@@ -57,18 +58,14 @@ void setRestClientCustomizers(List<RestClientCustomizer> customizers) {
 	 * @return the configured builder
 	 */
 	public RestClient.Builder configure(RestClient.Builder builder) {
-		ClientHttpRequestFactoryBuilder<?> requestFactoryBuilder = (this.requestFactoryBuilder != null)
-				? this.requestFactoryBuilder : ClientHttpRequestFactoryBuilder.detect();
-		builder.requestFactory(requestFactoryBuilder.build(this.requestFactorySettings));
+		builder.requestFactory(this.requestFactoryBuilder.build(this.requestFactorySettings));
 		applyCustomizers(builder);
 		return builder;
 	}
 
 	private void applyCustomizers(Builder builder) {
-		if (this.customizers != null) {
-			for (RestClientCustomizer customizer : this.customizers) {
-				customizer.customize(builder);
-			}
+		for (RestClientCustomizer customizer : this.customizers) {
+			customizer.customize(builder);
 		}
 	}
 

spring-boot-project/spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/web/client/RestClientAutoConfigurationTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2024 the original author or authors.
+ * Copyright 2012-2025 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.
@@ -24,6 +24,9 @@
 import org.springframework.boot.autoconfigure.http.HttpMessageConverters;
 import org.springframework.boot.autoconfigure.http.HttpMessageConvertersAutoConfiguration;
 import org.springframework.boot.autoconfigure.http.client.HttpClientAutoConfiguration;
+import org.springframework.boot.http.client.ClientHttpRequestFactoryBuilder;
+import org.springframework.boot.http.client.ClientHttpRequestFactorySettings;
+import org.springframework.boot.http.client.ClientHttpRequestFactorySettings.Redirects;
 import org.springframework.boot.ssl.SslBundles;
 import org.springframework.boot.test.context.runner.ApplicationContextRunner;
 import org.springframework.boot.web.client.RestClientCustomizer;
@@ -171,6 +174,57 @@ void whenHasFactoryProperty() {
 			});
 	}
 
+	@Test
+	void shouldSupplyRestClientBuilderConfigurerWithCustomSettings() {
+		ClientHttpRequestFactorySettings clientHttpRequestFactorySettings = ClientHttpRequestFactorySettings.defaults()
+			.withRedirects(Redirects.DONT_FOLLOW);
+		ClientHttpRequestFactoryBuilder<?> clientHttpRequestFactoryBuilder = mock(
+				ClientHttpRequestFactoryBuilder.class);
+		RestClientCustomizer customizer1 = mock(RestClientCustomizer.class);
+		RestClientCustomizer customizer2 = mock(RestClientCustomizer.class);
+		HttpMessageConvertersRestClientCustomizer httpMessageConverterCustomizer = mock(
+				HttpMessageConvertersRestClientCustomizer.class);
+		this.contextRunner.withBean(ClientHttpRequestFactorySettings.class, () -> clientHttpRequestFactorySettings)
+			.withBean(ClientHttpRequestFactoryBuilder.class, () -> clientHttpRequestFactoryBuilder)
+			.withBean("customizer1", RestClientCustomizer.class, () -> customizer1)
+			.withBean("customizer2", RestClientCustomizer.class, () -> customizer2)
+			.withBean("httpMessageConverterCustomizer", HttpMessageConvertersRestClientCustomizer.class,
+					() -> httpMessageConverterCustomizer)
+			.run((context) -> {
+				assertThat(context).hasSingleBean(RestClientBuilderConfigurer.class)
+					.hasSingleBean(ClientHttpRequestFactorySettings.class)
+					.hasSingleBean(ClientHttpRequestFactoryBuilder.class);
+				RestClientBuilderConfigurer configurer = context.getBean(RestClientBuilderConfigurer.class);
+				assertThat(configurer).hasFieldOrPropertyWithValue("requestFactoryBuilder",
+						clientHttpRequestFactoryBuilder);
+				assertThat(configurer).hasFieldOrPropertyWithValue("requestFactorySettings",
+						clientHttpRequestFactorySettings);
+				assertThat(configurer).hasFieldOrPropertyWithValue("customizers",
+						List.of(customizer1, customizer2, httpMessageConverterCustomizer));
+			});
+	}
+
+	@Test
+	void shouldSupplyRestClientBuilderConfigurerWithAutoConfiguredHttpSettings() {
+		RestClientCustomizer customizer1 = mock(RestClientCustomizer.class);
+		RestClientCustomizer customizer2 = mock(RestClientCustomizer.class);
+		this.contextRunner.withBean("customizer1", RestClientCustomizer.class, () -> customizer1)
+			.withBean("customizer2", RestClientCustomizer.class, () -> customizer2)
+			.run((context) -> {
+				assertThat(context).hasSingleBean(RestClientBuilderConfigurer.class)
+					.hasSingleBean(ClientHttpRequestFactorySettings.class)
+					.hasSingleBean(ClientHttpRequestFactoryBuilder.class)
+					.hasSingleBean(HttpMessageConvertersRestClientCustomizer.class);
+				RestClientBuilderConfigurer configurer = context.getBean(RestClientBuilderConfigurer.class);
+				assertThat(configurer).hasFieldOrPropertyWithValue("requestFactoryBuilder",
+						context.getBean(ClientHttpRequestFactoryBuilder.class));
+				assertThat(configurer).hasFieldOrPropertyWithValue("requestFactorySettings",
+						context.getBean(ClientHttpRequestFactorySettings.class));
+				assertThat(configurer).hasFieldOrPropertyWithValue("customizers", List.of(customizer1, customizer2,
+						context.getBean(HttpMessageConvertersRestClientCustomizer.class)));
+			});
+	}
+
 	@Configuration(proxyBeanMethods = false)
 	static class CodecConfiguration {
 

spring-boot-project/spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/web/client/RestClientBuilderConfigurerTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2023 the original author or authors.
+ * Copyright 2012-2025 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.
@@ -19,11 +19,19 @@
 import java.util.List;
 
 import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
+import org.mockito.Mock;
+import org.mockito.junit.jupiter.MockitoExtension;
 
+import org.springframework.boot.http.client.ClientHttpRequestFactoryBuilder;
+import org.springframework.boot.http.client.ClientHttpRequestFactorySettings;
+import org.springframework.boot.ssl.SslBundle;
 import org.springframework.boot.web.client.RestClientCustomizer;
+import org.springframework.http.client.ClientHttpRequestFactory;
 import org.springframework.web.client.RestClient;
 
-import static org.assertj.core.api.Assertions.assertThatCode;
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.mockito.BDDMockito.given;
 import static org.mockito.BDDMockito.then;
 import static org.mockito.Mockito.mock;
 
@@ -32,23 +40,29 @@
  *
  * @author Moritz Halbritter
  */
+@ExtendWith(MockitoExtension.class)
 class RestClientBuilderConfigurerTests {
 
+	@Mock
+	private ClientHttpRequestFactoryBuilder<ClientHttpRequestFactory> clientHttpRequestFactoryBuilder;
+
+	@Mock
+	private ClientHttpRequestFactory clientHttpRequestFactory;
+
 	@Test
-	void shouldApplyCustomizers() {
-		RestClientBuilderConfigurer configurer = new RestClientBuilderConfigurer();
+	void shouldConfigureRestClientBuilder() {
+		ClientHttpRequestFactorySettings settings = ClientHttpRequestFactorySettings.ofSslBundle(mock(SslBundle.class));
 		RestClientCustomizer customizer = mock(RestClientCustomizer.class);
-		configurer.setRestClientCustomizers(List.of(customizer));
+		RestClientCustomizer customizer1 = mock(RestClientCustomizer.class);
+		RestClientBuilderConfigurer configurer = new RestClientBuilderConfigurer(this.clientHttpRequestFactoryBuilder,
+				settings, List.of(customizer, customizer1));
+		given(this.clientHttpRequestFactoryBuilder.build(settings)).willReturn(this.clientHttpRequestFactory);
+
 		RestClient.Builder builder = RestClient.builder();
 		configurer.configure(builder);
+		assertThat(builder.build()).hasFieldOrPropertyWithValue("clientRequestFactory", this.clientHttpRequestFactory);
 		then(customizer).should().customize(builder);
-	}
-
-	@Test
-	void shouldSupportNullAsCustomizers() {
-		RestClientBuilderConfigurer configurer = new RestClientBuilderConfigurer();
-		configurer.setRestClientCustomizers(null);
-		assertThatCode(() -> configurer.configure(RestClient.builder())).doesNotThrowAnyException();
+		then(customizer1).should().customize(builder);
 	}
 
 }