Add RestClientAdapter

See gh-30869

spring-web/src/main/java/org/springframework/web/client/support/RestClientAdapter.java

@@ -0,0 +1,128 @@
+/*
+ * Copyright 2002-2023 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.web.client.support;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import org.springframework.core.ParameterizedTypeReference;
+import org.springframework.http.HttpCookie;
+import org.springframework.http.HttpHeaders;
+import org.springframework.http.HttpMethod;
+import org.springframework.http.ResponseEntity;
+import org.springframework.util.Assert;
+import org.springframework.web.client.RestClient;
+import org.springframework.web.service.invoker.HttpExchangeAdapter;
+import org.springframework.web.service.invoker.HttpRequestValues;
+import org.springframework.web.service.invoker.HttpServiceProxyFactory;
+
+/**
+ * {@link HttpExchangeAdapter} that enables an {@link HttpServiceProxyFactory} to use
+ * {@link RestClient} for request execution.
+ *
+ * <p>
+ * Use static factory methods in this class to create an {@link HttpServiceProxyFactory}
+ * configured with a given {@link RestClient}.
+ *
+ * @author Olga Maciaszek-Sharma
+ * @since 6.1
+ */
+public final class RestClientAdapter implements HttpExchangeAdapter {
+
+	private final RestClient restClient;
+
+	private RestClientAdapter(RestClient restClient) {
+		this.restClient = restClient;
+	}
+
+	@Override
+	public boolean supportsRequestAttributes() {
+		return true;
+	}
+
+	@Override
+	public void exchange(HttpRequestValues requestValues) {
+		newRequest(requestValues).retrieve().toBodilessEntity();
+	}
+
+	@Override
+	public HttpHeaders exchangeForHeaders(HttpRequestValues requestValues) {
+		return newRequest(requestValues).retrieve().toBodilessEntity().getHeaders();
+	}
+
+	@Override
+	public <T> T exchangeForBody(HttpRequestValues requestValues, ParameterizedTypeReference<T> bodyType) {
+		return newRequest(requestValues).retrieve().body(bodyType);
+	}
+
+	@Override
+	public ResponseEntity<Void> exchangeForBodilessEntity(HttpRequestValues requestValues) {
+		return newRequest(requestValues).retrieve().toBodilessEntity();
+	}
+
+	@Override
+	public <T> ResponseEntity<T> exchangeForEntity(HttpRequestValues requestValues,
+			ParameterizedTypeReference<T> bodyType) {
+		return newRequest(requestValues).retrieve().toEntity(bodyType);
+	}
+
+	private RestClient.RequestBodySpec newRequest(HttpRequestValues requestValues) {
+
+		HttpMethod httpMethod = requestValues.getHttpMethod();
+		Assert.notNull(httpMethod, "HttpMethod is required");
+
+		RestClient.RequestBodyUriSpec uriSpec = this.restClient.method(httpMethod);
+
+		RestClient.RequestBodySpec bodySpec;
+		if (requestValues.getUri() != null) {
+			bodySpec = uriSpec.uri(requestValues.getUri());
+		}
+		else if (requestValues.getUriTemplate() != null) {
+			bodySpec = uriSpec.uri(requestValues.getUriTemplate(), requestValues.getUriVariables());
+		}
+		else {
+			throw new IllegalStateException("Neither full URL nor URI template");
+		}
+
+		bodySpec.headers(headers -> headers.putAll(requestValues.getHeaders()));
+
+		if (!requestValues.getCookies().isEmpty()) {
+			List<String> cookies = new ArrayList<>();
+			requestValues.getCookies().forEach((name, values) -> values.forEach(value -> {
+				HttpCookie cookie = new HttpCookie(name, value);
+				cookies.add(cookie.toString());
+			}));
+			bodySpec.header(HttpHeaders.COOKIE, String.join("; ", cookies));
+		}
+
+		bodySpec.attributes(attributes -> attributes.putAll(requestValues.getAttributes()));
+
+		if (requestValues.getBodyValue() != null) {
+			bodySpec.body(requestValues.getBodyValue());
+		}
+
+		return bodySpec;
+	}
+
+	/**
+	 * Create a {@link RestClientAdapter} with the given {@link RestClient}.
+	 */
+	public static RestClientAdapter create(RestClient restClient) {
+		return new RestClientAdapter(restClient);
+	}
+
+}

spring-web/src/main/java/org/springframework/web/service/invoker/HttpServiceProxyFactory.java

@@ -55,6 +55,7 @@ import org.springframework.web.service.annotation.HttpExchange;
  * @since 6.0
  * @see org.springframework.web.client.support.RestTemplateAdapter
  * @see org.springframework.web.reactive.function.client.support.WebClientAdapter
+ * @see org.springframework.web.client.support.RestClientAdapter
  */
 public final class HttpServiceProxyFactory {