Add `redirects(...)` method to `RestTemplateBuilder`

Add `redirects(...)` method to `RestTemplateBuilder` to allow redirect
customization. This new method is required in 3.4 since the default
redirect strategy for some clients has changed and users need a way
to restore the old behavior.

See gh-43258

spring-boot-project/spring-boot-test/src/main/java/org/springframework/boot/test/web/client/TestRestTemplate.java

@@ -47,6 +47,7 @@ import org.apache.hc.core5.ssl.SSLContextBuilder;
 import org.apache.hc.core5.ssl.TrustStrategy;
 
 import org.springframework.boot.http.client.ClientHttpRequestFactorySettings;
+import org.springframework.boot.http.client.ClientHttpRequestFactorySettings.Redirects;
 import org.springframework.boot.web.client.RestTemplateBuilder;
 import org.springframework.boot.web.client.RootUriTemplateHandler;
 import org.springframework.core.ParameterizedTypeReference;
@@ -92,6 +93,7 @@ import org.springframework.web.util.UriTemplateHandler;
  * @author Andy Wilkinson
  * @author Kristine Jetzke
  * @author Dmytro Nosan
+ * @author Yanming Zhou
  * @since 1.4.0
  */
 public class TestRestTemplate {
@@ -946,6 +948,22 @@ public class TestRestTemplate {
 		return template;
 	}
 
+	/**
+	 * Creates a new {@code TestRestTemplate} with the same configuration as this one,
+	 * except that it will use the given {@code redirects} strategies. The request factory
+	 * used is a new instance of the underlying {@link RestTemplate}'s request factory
+	 * type (when possible).
+	 * @param redirects the redirects
+	 * @return the new template
+	 * @since 3.4.1
+	 */
+	public TestRestTemplate withRedirects(Redirects redirects) {
+		TestRestTemplate template = new TestRestTemplate(this.builder.redirects(redirects), null, null,
+				this.httpClientOptions);
+		template.setUriTemplateHandler(getRestTemplate().getUriTemplateHandler());
+		return template;
+	}
+
 	@SuppressWarnings({ "rawtypes", "unchecked" })
 	private RequestEntity<?> createRequestEntityWithRootAppliedUri(RequestEntity<?> requestEntity) {
 		return new RequestEntity(requestEntity.getBody(), requestEntity.getHeaders(), requestEntity.getMethod(),
@@ -988,7 +1006,10 @@ public class TestRestTemplate {
 
 		/**
 		 * Enable redirects.
+		 * @deprecated since 3.4.1 for removal in 3.6.0 in favor of
+		 * {@link #withRedirects(Redirects)}
 		 */
+		@Deprecated(since = "3.4.1", forRemoval = true)
 		ENABLE_REDIRECTS,
 
 		/**
@@ -1032,7 +1053,8 @@ public class TestRestTemplate {
 			Set<HttpClientOption> options = new HashSet<>(Arrays.asList(httpClientOptions));
 			this.cookieSpec = (options.contains(HttpClientOption.ENABLE_COOKIES) ? StandardCookieSpec.STRICT
 					: StandardCookieSpec.IGNORE);
-			this.enableRedirects = options.contains(HttpClientOption.ENABLE_REDIRECTS);
+			this.enableRedirects = options.contains(HttpClientOption.ENABLE_REDIRECTS)
+					|| settings.redirects() != Redirects.DONT_FOLLOW;
 			boolean ssl = options.contains(HttpClientOption.SSL);
 			if (settings.readTimeout() != null || ssl) {
 				setHttpClient(createHttpClient(settings.readTimeout(), ssl));

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

@@ -26,6 +26,7 @@ import java.util.stream.Stream;
 import org.apache.hc.client5.http.config.RequestConfig;
 import org.junit.jupiter.api.Test;
 
+import org.springframework.boot.http.client.ClientHttpRequestFactorySettings.Redirects;
 import org.springframework.boot.test.web.client.TestRestTemplate.CustomHttpComponentsClientHttpRequestFactory;
 import org.springframework.boot.test.web.client.TestRestTemplate.HttpClientOption;
 import org.springframework.boot.web.client.RestTemplateBuilder;
@@ -66,6 +67,7 @@ import static org.mockito.Mockito.mock;
  * @author Stephane Nicoll
  * @author Andy Wilkinson
  * @author Kristine Jetzke
+ * @author Yanming Zhou
  */
 class TestRestTemplateTests {
 
@@ -129,6 +131,7 @@ class TestRestTemplateTests {
 		assertBasicAuthorizationCredentials(restTemplate, "user", "password");
 	}
 
+	@SuppressWarnings("deprecation")
 	@Test
 	void options() {
 		TestRestTemplate template = new TestRestTemplate(HttpClientOption.ENABLE_REDIRECTS);
@@ -139,6 +142,21 @@ class TestRestTemplateTests {
 		assertThat(config.isRedirectsEnabled()).isTrue();
 	}
 
+	@Test
+	void redirects() {
+		TestRestTemplate template = new TestRestTemplate().withRedirects(Redirects.DONT_FOLLOW);
+		CustomHttpComponentsClientHttpRequestFactory factory = (CustomHttpComponentsClientHttpRequestFactory) template
+			.getRestTemplate()
+			.getRequestFactory();
+		RequestConfig config = factory.createRequestConfig();
+		assertThat(config.isRedirectsEnabled()).isFalse();
+
+		template = new TestRestTemplate().withRedirects(Redirects.FOLLOW);
+		factory = (CustomHttpComponentsClientHttpRequestFactory) template.getRestTemplate().getRequestFactory();
+		config = factory.createRequestConfig();
+		assertThat(config.isRedirectsEnabled()).isTrue();
+	}
+
 	@Test
 	void restOperationsAreAvailable() {
 		RestTemplate delegate = mock(RestTemplate.class);

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

@@ -33,6 +33,7 @@ import java.util.function.Supplier;
 import org.springframework.beans.BeanUtils;
 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.SslBundle;
 import org.springframework.http.client.ClientHttpRequest;
 import org.springframework.http.client.ClientHttpRequestFactory;
@@ -64,6 +65,7 @@ import org.springframework.web.util.UriTemplateHandler;
  * @author Kevin Strijbos
  * @author Ilya Lukyanovich
  * @author Scott Frederick
+ * @author Yanming Zhou
  * @since 1.4.0
  */
 public class RestTemplateBuilder {
@@ -501,6 +503,19 @@ public class RestTemplateBuilder {
 				this.defaultHeaders, this.customizers, this.requestCustomizers);
 	}
 
+	/**
+	 * Sets the redirect strategy on the underlying {@link ClientHttpRequestFactory}.
+	 * @param redirects the redirect strategy
+	 * @return a new builder instance.
+	 * @since 3.4.1
+	 */
+	public RestTemplateBuilder redirects(Redirects redirects) {
+		return new RestTemplateBuilder(this.requestFactorySettings.withRedirects(redirects), this.detectRequestFactory,
+				this.rootUri, this.messageConverters, this.interceptors, this.requestFactoryBuilder,
+				this.uriTemplateHandler, this.errorHandler, this.basicAuthentication, this.defaultHeaders,
+				this.customizers, this.requestCustomizers);
+	}
+
 	/**
 	 * Sets the SSL bundle on the underlying {@link ClientHttpRequestFactory}.
 	 * @param sslBundle the SSL bundle

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

@@ -32,6 +32,7 @@ import org.mockito.Mock;
 import org.mockito.junit.jupiter.MockitoExtension;
 
 import org.springframework.boot.http.client.ClientHttpRequestFactorySettings;
+import org.springframework.boot.http.client.ClientHttpRequestFactorySettings.Redirects;
 import org.springframework.http.HttpHeaders;
 import org.springframework.http.HttpMethod;
 import org.springframework.http.MediaType;
@@ -73,6 +74,7 @@ import static org.springframework.test.web.client.response.MockRestResponseCreat
  * @author Kevin Strijbos
  * @author Ilya Lukyanovich
  * @author Brian Clozel
+ * @author Yanming Zhou
  */
 @ExtendWith(MockitoExtension.class)
 class RestTemplateBuilderTests {
@@ -486,6 +488,13 @@ class RestTemplateBuilderTests {
 		assertThat(template.getRequestFactory()).isInstanceOf(BufferingClientHttpRequestFactory.class);
 	}
 
+	@Test
+	void configureRedirects() {
+		assertThat(this.builder.redirects(Redirects.DONT_FOLLOW)).extracting("requestFactorySettings")
+			.extracting("redirects")
+			.isSameAs(Redirects.DONT_FOLLOW);
+	}
+
 	private ClientHttpRequest createRequest(RestTemplate template) {
 		return ReflectionTestUtils.invokeMethod(template, "createRequest", URI.create("http://localhost"),
 				HttpMethod.GET);