Support declarative HTTP Service clients

Add auto-configuration support for Spring Framework's HTTP Service
clients, supporting both `RestClient` and `WebClient` client types.

Configuration properties are provided under `spring.http.client.service`
and `spring.http.reactiveclient.service` names. Group specific
properties are available under `....service.group.<name>.`.

Auto-configuration support includes automatic registration of user
defined `HttpServiceGroupConfigurer` beans. `RestClientCustomizer` and
`WebClientCustomizer` beans are also supported.

Closes gh-31337

Co-authored-by: Rossen Stoyanchev <[email protected]>
Co-authored-by: Phillip Webb <[email protected]>

Author: 3 people

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/http/client/ClientHttpRequestFactories.java

@@ -21,7 +21,7 @@
 import java.util.function.Function;
 import java.util.function.Predicate;
 
-import org.springframework.beans.factory.ObjectProvider;
+import org.springframework.beans.factory.ObjectFactory;
 import org.springframework.boot.autoconfigure.http.client.AbstractHttpClientProperties.Ssl;
 import org.springframework.boot.autoconfigure.http.client.AbstractHttpRequestFactoryProperties.Factory;
 import org.springframework.boot.http.client.ClientHttpRequestFactoryBuilder;
@@ -37,25 +37,26 @@
  * {@link ClientHttpRequestFactorySettings}.
  *
  * @author Phillip Webb
+ * @since 4.0.0
  */
-class ClientHttpRequestFactories {
+public final class ClientHttpRequestFactories {
 
-	private final ObjectProvider<SslBundles> sslBundles;
+	private final ObjectFactory<SslBundles> sslBundles;
 
 	private final AbstractHttpRequestFactoryProperties[] orderedProperties;
 
-	ClientHttpRequestFactories(ObjectProvider<SslBundles> sslBundles,
+	public ClientHttpRequestFactories(ObjectFactory<SslBundles> sslBundles,
 			AbstractHttpRequestFactoryProperties... orderedProperties) {
 		this.sslBundles = sslBundles;
 		this.orderedProperties = orderedProperties;
 	}
 
-	ClientHttpRequestFactoryBuilder<?> builder(ClassLoader classLoader) {
+	public ClientHttpRequestFactoryBuilder<?> builder(ClassLoader classLoader) {
 		Factory factory = getProperty(AbstractHttpRequestFactoryProperties::getFactory);
 		return (factory != null) ? factory.builder() : ClientHttpRequestFactoryBuilder.detect(classLoader);
 	}
 
-	ClientHttpRequestFactorySettings settings() {
+	public ClientHttpRequestFactorySettings settings() {
 		HttpRedirects redirects = getProperty(AbstractHttpRequestFactoryProperties::getRedirects);
 		Duration connectTimeout = getProperty(AbstractHttpRequestFactoryProperties::getConnectTimeout);
 		Duration readTimeout = getProperty(AbstractHttpRequestFactoryProperties::getReadTimeout);

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/http/client/reactive/ClientHttpConnectors.java

@@ -21,7 +21,7 @@
 import java.util.function.Function;
 import java.util.function.Predicate;
 
-import org.springframework.beans.factory.ObjectProvider;
+import org.springframework.beans.factory.ObjectFactory;
 import org.springframework.boot.autoconfigure.http.client.AbstractHttpClientProperties.Ssl;
 import org.springframework.boot.autoconfigure.http.client.reactive.AbstractClientHttpConnectorProperties.Connector;
 import org.springframework.boot.http.client.HttpRedirects;
@@ -36,25 +36,26 @@
  * {@link ClientHttpConnectorSettings}.
  *
  * @author Phillip Webb
+ * @since 4.0.0
  */
-class ClientHttpConnectors {
+public final class ClientHttpConnectors {
 
-	private final ObjectProvider<SslBundles> sslBundles;
+	private final ObjectFactory<SslBundles> sslBundles;
 
 	private final AbstractClientHttpConnectorProperties[] orderedProperties;
 
-	ClientHttpConnectors(ObjectProvider<SslBundles> sslBundles,
+	public ClientHttpConnectors(ObjectFactory<SslBundles> sslBundles,
 			AbstractClientHttpConnectorProperties... orderedProperties) {
 		this.sslBundles = sslBundles;
 		this.orderedProperties = orderedProperties;
 	}
 
-	ClientHttpConnectorBuilder<?> builder(ClassLoader classLoader) {
+	public ClientHttpConnectorBuilder<?> builder(ClassLoader classLoader) {
 		Connector connector = getProperty(AbstractClientHttpConnectorProperties::getConnector);
 		return (connector != null) ? connector.builder() : ClientHttpConnectorBuilder.detect(classLoader);
 	}
 
-	ClientHttpConnectorSettings settings() {
+	public ClientHttpConnectorSettings settings() {
 		HttpRedirects redirects = getProperty(AbstractClientHttpConnectorProperties::getRedirects);
 		Duration connectTimeout = getProperty(AbstractClientHttpConnectorProperties::getConnectTimeout);
 		Duration readTimeout = getProperty(AbstractClientHttpConnectorProperties::getReadTimeout);

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/http/client/reactive/service/AbstractHttpReactiveClientServiceProperties.java

@@ -0,0 +1,63 @@
+/*
+ * 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.
+ * 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.boot.autoconfigure.http.client.reactive.service;
+
+import java.util.LinkedHashMap;
+import java.util.List;
+import java.util.Map;
+
+import org.springframework.boot.autoconfigure.http.client.reactive.AbstractClientHttpConnectorProperties;
+
+/**
+ * {@link AbstractClientHttpConnectorProperties} for reactive HTTP Service clients.
+ *
+ * @author Olga Maciaszek-Sharma
+ * @author Rossen Stoyanchev
+ * @author Phillip Webb
+ * @since 4.0.0
+ */
+public abstract class AbstractHttpReactiveClientServiceProperties extends AbstractClientHttpConnectorProperties {
+
+	/**
+	 * Base url to set in the underlying HTTP client group. By default, set to
+	 * {@code null}.
+	 */
+	private String baseUrl;
+
+	/**
+	 * Default request headers for interface client group. By default, set to empty
+	 * {@link Map}.
+	 */
+	private Map<String, List<String>> defaultHeader = new LinkedHashMap<>();
+
+	public String getBaseUrl() {
+		return this.baseUrl;
+	}
+
+	public void setBaseUrl(String baseUrl) {
+		this.baseUrl = baseUrl;
+	}
+
+	public Map<String, List<String>> getDefaultHeader() {
+		return this.defaultHeader;
+	}
+
+	public void setDefaultHeader(Map<String, List<String>> defaultHeaders) {
+		this.defaultHeader = defaultHeaders;
+	}
+
+}

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/http/client/reactive/service/ReactiveHttpClientServiceProperties.java

@@ -0,0 +1,55 @@
+/*
+ * 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.
+ * 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.boot.autoconfigure.http.client.reactive.service;
+
+import java.util.LinkedHashMap;
+import java.util.Map;
+
+import org.springframework.boot.context.properties.ConfigurationProperties;
+
+/**
+ * Properties for Reactive HTTP Service clients.
+ *
+ * @author Olga Maciaszek-Sharma
+ * @author Rossen Stoyanchev
+ * @author Phillip Webb
+ * @since 4.0.0
+ */
+@ConfigurationProperties("spring.http.reactiveclient.service")
+public class ReactiveHttpClientServiceProperties extends AbstractHttpReactiveClientServiceProperties {
+
+	/**
+	 * Group settings.
+	 */
+	private Map<String, Group> group = new LinkedHashMap<>();
+
+	public Map<String, Group> getGroup() {
+		return this.group;
+	}
+
+	public void setGroup(Map<String, Group> group) {
+		this.group = group;
+	}
+
+	/**
+	 * Properties for a single HTTP Service client group.
+	 */
+	public static class Group extends AbstractHttpReactiveClientServiceProperties {
+
+	}
+
+}

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/http/client/reactive/service/ReactiveHttpServiceClientAutoConfiguration.java

@@ -0,0 +1,80 @@
+/*
+ * 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.
+ * 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.boot.autoconfigure.http.client.reactive.service;
+
+import org.springframework.beans.factory.BeanClassLoaderAware;
+import org.springframework.beans.factory.ObjectProvider;
+import org.springframework.boot.autoconfigure.AutoConfiguration;
+import org.springframework.boot.autoconfigure.condition.ConditionalOnBean;
+import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
+import org.springframework.boot.autoconfigure.http.client.reactive.ClientHttpConnectorAutoConfiguration;
+import org.springframework.boot.autoconfigure.http.client.reactive.HttpReactiveClientProperties;
+import org.springframework.boot.autoconfigure.web.reactive.function.client.WebClientAutoConfiguration;
+import org.springframework.boot.context.properties.EnableConfigurationProperties;
+import org.springframework.boot.http.client.reactive.ClientHttpConnectorBuilder;
+import org.springframework.boot.http.client.reactive.ClientHttpConnectorSettings;
+import org.springframework.boot.ssl.SslBundles;
+import org.springframework.boot.web.reactive.function.client.WebClientCustomizer;
+import org.springframework.context.annotation.Bean;
+import org.springframework.web.reactive.function.client.support.WebClientAdapter;
+import org.springframework.web.service.registry.HttpServiceProxyRegistry;
+import org.springframework.web.service.registry.ImportHttpServices;
+
+/**
+ * AutoConfiguration for Spring reactive HTTP Service Clients.
+ * <p>
+ * This will result in the creation of reactive HTTP Service client beans defined by
+ * {@link ImportHttpServices @ImportHttpServices} annotations.
+ *
+ * @author Olga Maciaszek-Sharma
+ * @author Rossen Stoyanchev
+ * @author Phillip Webb
+ * @since 4.0.0
+ */
+@AutoConfiguration(after = { ClientHttpConnectorAutoConfiguration.class, WebClientAutoConfiguration.class })
+@ConditionalOnClass(WebClientAdapter.class)
+@ConditionalOnBean(HttpServiceProxyRegistry.class)
+@EnableConfigurationProperties(ReactiveHttpClientServiceProperties.class)
+public class ReactiveHttpServiceClientAutoConfiguration implements BeanClassLoaderAware {
+
+	private ClassLoader beanClassLoader;
+
+	ReactiveHttpServiceClientAutoConfiguration() {
+	}
+
+	@Override
+	public void setBeanClassLoader(ClassLoader classLoader) {
+		this.beanClassLoader = classLoader;
+	}
+
+	@Bean
+	WebClientPropertiesHttpServiceGroupConfigurer webClientPropertiesHttpServiceGroupConfigurer(
+			ObjectProvider<SslBundles> sslBundles, HttpReactiveClientProperties httpReactiveClientProperties,
+			ReactiveHttpClientServiceProperties serviceProperties,
+			ObjectProvider<ClientHttpConnectorBuilder<?>> clientConnectorBuilder,
+			ObjectProvider<ClientHttpConnectorSettings> clientConnectorSettings) {
+		return new WebClientPropertiesHttpServiceGroupConfigurer(this.beanClassLoader, sslBundles,
+				httpReactiveClientProperties, serviceProperties, clientConnectorBuilder, clientConnectorSettings);
+	}
+
+	@Bean
+	WebClientCustomizerHttpServiceGroupConfigurer webClientCustomizerHttpServiceGroupConfigurer(
+			ObjectProvider<WebClientCustomizer> customizers) {
+		return new WebClientCustomizerHttpServiceGroupConfigurer(customizers);
+	}
+
+}

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/http/client/reactive/service/WebClientCustomizerHttpServiceGroupConfigurer.java

@@ -0,0 +1,61 @@
+/*
+ * 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.
+ * 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.boot.autoconfigure.http.client.reactive.service;
+
+import org.springframework.beans.factory.ObjectProvider;
+import org.springframework.boot.web.client.RestClientCustomizer;
+import org.springframework.boot.web.reactive.function.client.WebClientCustomizer;
+import org.springframework.web.client.RestClient;
+import org.springframework.web.client.support.RestClientHttpServiceGroupConfigurer;
+import org.springframework.web.reactive.function.client.WebClient;
+import org.springframework.web.reactive.function.client.support.WebClientHttpServiceGroupConfigurer;
+
+/**
+ * A {@link RestClientHttpServiceGroupConfigurer} to apply auto-configured
+ * {@link RestClientCustomizer} beans to the group's {@link RestClient}.
+ *
+ * @author Olga Maciaszek-Sharma
+ * @author Phillip Webb
+ */
+class WebClientCustomizerHttpServiceGroupConfigurer implements WebClientHttpServiceGroupConfigurer {
+
+	/**
+	 * Allow user defined configurers to apply before / after ours.
+	 */
+	private static final int ORDER = 0;
+
+	private final ObjectProvider<WebClientCustomizer> customizers;
+
+	WebClientCustomizerHttpServiceGroupConfigurer(ObjectProvider<WebClientCustomizer> customizers) {
+		this.customizers = customizers;
+	}
+
+	@Override
+	public int getOrder() {
+		return ORDER;
+	}
+
+	@Override
+	public void configureGroups(Groups<WebClient.Builder> groups) {
+		groups.configureClient(this::configureClient);
+	}
+
+	private void configureClient(WebClient.Builder builder) {
+		this.customizers.orderedStream().forEach((customizer) -> customizer.customize(builder));
+	}
+
+}