Allow for RestTemplate customization

This commit reuses the `RestTemplateBuilder` infrastructure wherever
a `RestTemplate` is required. This allows to customize the rest template
if necessary.

Closes gh-481

initializr-web/src/main/java/io/spring/initializr/web/autoconfigure/InitializrAutoConfiguration.java

@@ -18,6 +18,7 @@ package io.spring.initializr.web.autoconfigure;
 
 import java.util.ArrayList;
 import java.util.List;
+
 import javax.cache.configuration.MutableConfiguration;
 import javax.cache.expiry.CreatedExpiryPolicy;
 import javax.cache.expiry.Duration;
@@ -43,12 +44,14 @@ import org.springframework.boot.autoconfigure.cache.CacheAutoConfiguration;
 import org.springframework.boot.autoconfigure.cache.JCacheManagerCustomizer;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
+import org.springframework.boot.autoconfigure.condition.ConditionalOnWebApplication;
+import org.springframework.boot.autoconfigure.web.WebClientAutoConfiguration;
 import org.springframework.boot.bind.RelaxedPropertyResolver;
 import org.springframework.boot.context.properties.EnableConfigurationProperties;
+import org.springframework.boot.web.client.RestTemplateBuilder;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.core.env.Environment;
-import org.springframework.web.client.RestTemplate;
 import org.springframework.web.servlet.resource.ResourceUrlProvider;
 
 /**
@@ -64,7 +67,7 @@ import org.springframework.web.servlet.resource.ResourceUrlProvider;
  */
 @Configuration
 @EnableConfigurationProperties(InitializrProperties.class)
-@AutoConfigureAfter(CacheAutoConfiguration.class)
+@AutoConfigureAfter({ CacheAutoConfiguration.class, WebClientAutoConfiguration.class })
 public class InitializrAutoConfiguration {
 
 	private final List<ProjectRequestPostProcessor> postProcessors;
@@ -75,30 +78,6 @@ public class InitializrAutoConfiguration {
 		this.postProcessors = list != null ? list : new ArrayList<>();
 	}
 
-	@Bean
-	public WebConfig webConfig() {
-		return new WebConfig();
-	}
-
-	@Bean
-	@ConditionalOnMissingBean
-	public MainController initializrMainController(
-			InitializrMetadataProvider metadataProvider,
-			TemplateRenderer templateRenderer,
-			ResourceUrlProvider resourceUrlProvider,
-			ProjectGenerator projectGenerator,
-			DependencyMetadataProvider dependencyMetadataProvider) {
-		return new MainController(metadataProvider, templateRenderer, resourceUrlProvider
-				, projectGenerator, dependencyMetadataProvider);
-	}
-
-	@Bean
-	@ConditionalOnMissingBean
-	public UiController initializrUiController(
-			InitializrMetadataProvider metadataProvider) {
-		return new UiController(metadataProvider);
-	}
-
 	@Bean
 	@ConditionalOnMissingBean
 	public ProjectGenerator projectGenerator() {
@@ -130,10 +109,12 @@ public class InitializrAutoConfiguration {
 	@Bean
 	@ConditionalOnMissingBean(InitializrMetadataProvider.class)
 	public InitializrMetadataProvider initializrMetadataProvider(
-			InitializrProperties properties) {
+			InitializrProperties properties,
+			RestTemplateBuilder restTemplateBuilder) {
 		InitializrMetadata metadata = InitializrMetadataBuilder
 				.fromInitializrProperties(properties).build();
-		return new DefaultInitializrMetadataProvider(metadata, new RestTemplate());
+		return new DefaultInitializrMetadataProvider(metadata,
+				restTemplateBuilder.build());
 	}
 
 	@Bean
@@ -142,9 +123,40 @@ public class InitializrAutoConfiguration {
 		return new DefaultDependencyMetadataProvider();
 	}
 
+	@Configuration
+	@ConditionalOnWebApplication
+	static class InitializrWebConfiguration {
+
+
+		@Bean
+		public WebConfig webConfig() {
+			return new WebConfig();
+		}
+
+		@Bean
+		@ConditionalOnMissingBean
+		public MainController initializrMainController(
+				InitializrMetadataProvider metadataProvider,
+				TemplateRenderer templateRenderer,
+				ResourceUrlProvider resourceUrlProvider,
+				ProjectGenerator projectGenerator,
+				DependencyMetadataProvider dependencyMetadataProvider) {
+			return new MainController(metadataProvider, templateRenderer, resourceUrlProvider
+					, projectGenerator, dependencyMetadataProvider);
+		}
+
+		@Bean
+		@ConditionalOnMissingBean
+		public UiController initializrUiController(
+				InitializrMetadataProvider metadataProvider) {
+			return new UiController(metadataProvider);
+		}
+
+	}
+
 	@Configuration
 	@ConditionalOnClass(javax.cache.CacheManager.class)
-	static class CacheConfiguration {
+	static class InitializrCacheConfiguration {
 
 		@Bean
 		public JCacheManagerCustomizer initializrCacheManagerCustomizer() {

initializr-web/src/test/java/io/spring/initializr/web/autoconfigure/InitializrAutoConfigurationTests.java

@@ -0,0 +1,87 @@
+/*
+ * Copyright 2012-2017 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
+ *
+ *      http://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 io.spring.initializr.web.autoconfigure;
+
+import io.spring.initializr.metadata.InitializrMetadataProvider;
+import org.junit.After;
+import org.junit.Test;
+
+import org.springframework.beans.DirectFieldAccessor;
+import org.springframework.boot.autoconfigure.web.WebClientAutoConfiguration;
+import org.springframework.boot.test.util.EnvironmentTestUtils;
+import org.springframework.boot.web.client.RestTemplateCustomizer;
+import org.springframework.context.ConfigurableApplicationContext;
+import org.springframework.context.annotation.AnnotationConfigApplicationContext;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.web.client.ResponseErrorHandler;
+import org.springframework.web.client.RestTemplate;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.mockito.Mockito.mock;
+
+/**
+ * Tests for {@link InitializrAutoConfiguration}.
+ *
+ * @author Stephane Nicoll
+ */
+public class InitializrAutoConfigurationTests {
+
+	private ConfigurableApplicationContext context;
+
+	@After
+	public void close() {
+		if (this.context != null) {
+			this.context.close();
+		}
+	}
+
+	@Test
+	public void customRestTemplateBuilderIsUsed() {
+		load(CustomRestTemplateConfiguration.class);
+		assertThat(this.context.getBeansOfType(InitializrMetadataProvider.class))
+				.hasSize(1);
+		RestTemplate restTemplate = (RestTemplate) new DirectFieldAccessor(
+				this.context.getBean(InitializrMetadataProvider.class))
+				.getPropertyValue("restTemplate");
+		assertThat(restTemplate.getErrorHandler()).isSameAs(
+				CustomRestTemplateConfiguration.errorHandler);
+	}
+
+	private void load(Class<?> config, String... environment) {
+		AnnotationConfigApplicationContext ctx = new AnnotationConfigApplicationContext();
+		EnvironmentTestUtils.addEnvironment(ctx, environment);
+		if (config != null) {
+			ctx.register(config);
+		}
+		ctx.register(WebClientAutoConfiguration.class, InitializrAutoConfiguration.class);
+		ctx.refresh();
+		this.context = ctx;
+	}
+
+	@Configuration
+	static class CustomRestTemplateConfiguration {
+
+		private static final ResponseErrorHandler errorHandler = mock(ResponseErrorHandler.class);
+
+		@Bean
+		public RestTemplateCustomizer testRestTemplateCustomizer() {
+			return b -> b.setErrorHandler(errorHandler);
+		}
+	}
+
+}