Make JDK HttpClient customizable (#1000)

Author: driverpt

spring-cloud-openfeign-core/src/main/java/org/springframework/cloud/openfeign/clientconfig/Http2ClientFeignConfiguration.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2013-2023 the original author or authors.
+ * Copyright 2013-2024 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.
@@ -18,8 +18,10 @@
 
 import java.net.http.HttpClient;
 import java.time.Duration;
+import java.util.List;
 
 import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
+import org.springframework.cloud.openfeign.clientconfig.http2client.Http2ClientCustomizer;
 import org.springframework.cloud.openfeign.support.FeignHttpClientProperties;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
@@ -28,18 +30,26 @@
  * Default configuration for {@link HttpClient}.
  *
  * @author changjin wei(魏昌进)
+ * @author Luis Duarte
  */
 @Configuration(proxyBeanMethods = false)
 @ConditionalOnMissingBean(HttpClient.class)
 public class Http2ClientFeignConfiguration {
 
 	@Bean
-	public HttpClient httpClient(FeignHttpClientProperties httpClientProperties) {
+	@ConditionalOnMissingBean
+	public HttpClient.Builder httpClientBuilder(FeignHttpClientProperties httpClientProperties) {
 		return HttpClient.newBuilder()
 				.followRedirects(httpClientProperties.isFollowRedirects() ? HttpClient.Redirect.ALWAYS
 						: HttpClient.Redirect.NEVER)
 				.version(HttpClient.Version.valueOf(httpClientProperties.getHttp2().getVersion()))
-				.connectTimeout(Duration.ofMillis(httpClientProperties.getConnectionTimeout())).build();
+				.connectTimeout(Duration.ofMillis(httpClientProperties.getConnectionTimeout()));
+	}
+
+	@Bean
+	public HttpClient httpClient(HttpClient.Builder httpClientBuilder, List<Http2ClientCustomizer> customizers) {
+		customizers.forEach(customizer -> customizer.customize(httpClientBuilder));
+		return httpClientBuilder.build();
 	}
 
 }

spring-cloud-openfeign-core/src/main/java/org/springframework/cloud/openfeign/clientconfig/http2client/Http2ClientCustomizer.java

@@ -0,0 +1,38 @@
+/*
+ * Copyright 2013-2024 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.cloud.openfeign.clientconfig.http2client;
+
+import java.net.http.HttpClient;
+
+/**
+ * Callback interface that can be implemented by beans wishing to further customize the
+ * {@link HttpClient} through {@link HttpClient.Builder} retaining its default
+ * auto-configuration.
+ *
+ * @author Luís Duarte
+ * @since 4.1.1
+ */
+@FunctionalInterface
+public interface Http2ClientCustomizer {
+
+	/**
+	 * Customize JDK's HttpClient.
+	 * @param builder the HttpClient.Builder to customize
+	 */
+	void customize(HttpClient.Builder builder);
+
+}

spring-cloud-openfeign-core/src/test/java/org/springframework/cloud/openfeign/FeignHttp2ClientConfigurationTests.java

@@ -32,6 +32,7 @@
 
 /**
  * @author changjin wei(魏昌进)
+ * @author Luis Duarte
  */
 class FeignHttp2ClientConfigurationTests {
 

spring-cloud-openfeign-core/src/test/java/org/springframework/cloud/openfeign/test/Http2ClientConfigurationTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2013-2023 the original author or authors.
+ * Copyright 2013-2024 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.
@@ -16,6 +16,8 @@
 
 package org.springframework.cloud.openfeign.test;
 
+import java.net.InetSocketAddress;
+import java.net.ProxySelector;
 import java.net.http.HttpClient;
 
 import feign.Client;
@@ -27,6 +29,7 @@
 import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
 import org.springframework.boot.test.context.SpringBootTest;
 import org.springframework.cloud.openfeign.FeignClient;
+import org.springframework.cloud.openfeign.clientconfig.http2client.Http2ClientCustomizer;
 import org.springframework.cloud.openfeign.loadbalancer.FeignBlockingLoadBalancerClient;
 import org.springframework.context.annotation.Bean;
 import org.springframework.test.annotation.DirtiesContext;
@@ -45,15 +48,21 @@ class Http2ClientConfigurationTests {
 	@Autowired
 	FeignBlockingLoadBalancerClient feignClient;
 
-	private static final HttpClient defaultHttpClient = HttpClient.newHttpClient();
+	@Autowired
+	HttpClient underlyingHttpClient;
 
 	@Test
 	void shouldInstantiateFeignHttp2Client() {
 		Client delegate = feignClient.getDelegate();
 		assertThat(delegate instanceof Http2Client).isTrue();
 		Http2Client http2Client = (Http2Client) delegate;
 		HttpClient httpClient = getField(http2Client, "client");
-		assertThat(httpClient).isEqualTo(defaultHttpClient);
+		assertThat(httpClient).isEqualTo(underlyingHttpClient);
+	}
+
+	@Test
+	void customizesHttpClient() {
+		assertThat(underlyingHttpClient.proxy()).isNotEmpty();
 	}
 
 	@SuppressWarnings("unchecked")
@@ -72,8 +81,9 @@ interface FooClient {
 	static class TestConfig {
 
 		@Bean
-		public HttpClient client() {
-			return defaultHttpClient;
+		public Http2ClientCustomizer customizer() {
+			return builder -> builder
+				.proxy(ProxySelector.of(new InetSocketAddress("localhost", 1234)));
 		}
 
 	}