Add support for RestClient API (#75)

Fixes #74.

belgif-rest-problem-it/belgif-rest-problem-spring-boot-3-it/src/main/java/io/github/belgif/rest/problem/Client.java

@@ -2,6 +2,6 @@
 
 public enum Client {
 
-    REST_TEMPLATE, WEB_CLIENT
+    REST_TEMPLATE, WEB_CLIENT, REST_CLIENT
 
 }

belgif-rest-problem-it/belgif-rest-problem-spring-boot-3-it/src/main/java/io/github/belgif/rest/problem/FrontendController.java

@@ -11,6 +11,7 @@
 import org.springframework.http.ResponseEntity;
 import org.springframework.validation.annotation.Validated;
 import org.springframework.web.bind.annotation.*;
+import org.springframework.web.client.RestClient;
 import org.springframework.web.client.RestTemplate;
 import org.springframework.web.reactive.function.client.WebClient;
 
@@ -33,13 +34,20 @@ public class FrontendController implements ControllerInterface {
 
     private final WebClient.Builder webClientBuilder;
 
+    private final RestClient.Builder restClientBuilder;
+
     private RestTemplate restTemplate;
 
     private WebClient webClient;
 
-    public FrontendController(RestTemplateBuilder restTemplateBuilder, WebClient.Builder webClientBuilder) {
+    private RestClient restClient;
+
+    public FrontendController(RestTemplateBuilder restTemplateBuilder,
+            WebClient.Builder webClientBuilder,
+            RestClient.Builder restClientBuilder) {
         this.restTemplateBuilder = restTemplateBuilder;
         this.webClientBuilder = webClientBuilder;
+        this.restClientBuilder = restClientBuilder;
     }
 
     @EventListener
@@ -48,7 +56,11 @@ public void onApplicationEvent(ServletWebServerInitializedEvent event) {
                 .rootUri("http://localhost:" + event.getWebServer().getPort() + "/spring/backend")
                 .build();
         this.webClient = webClientBuilder
-                .baseUrl("http://localhost:" + event.getWebServer().getPort() + "/spring/backend").build();
+                .baseUrl("http://localhost:" + event.getWebServer().getPort() + "/spring/backend")
+                .build();
+        this.restClient = restClientBuilder
+                .baseUrl("http://localhost:" + event.getWebServer().getPort() + "/spring/backend")
+                .build();
     }
 
     @GetMapping("/badRequest")
@@ -90,6 +102,8 @@ public void badRequestFromBackend(@RequestParam("client") Client client) {
                 restTemplate.getForObject("/badRequest", String.class);
             } else if (client == Client.WEB_CLIENT) {
                 webClient.get().uri("/badRequest").retrieve().toEntity(String.class).block();
+            } else if (client == Client.REST_CLIENT) {
+                restClient.get().uri("/badRequest").retrieve().toEntity(String.class);
             }
             throw new IllegalStateException(ILLEGAL_STATE_MESSAGE_PREFIX + client);
         } catch (BadRequestProblem e) {
@@ -105,6 +119,8 @@ public void customFromBackend(@RequestParam("client") Client client) {
                 restTemplate.getForObject("/custom", String.class);
             } else if (client == Client.WEB_CLIENT) {
                 webClient.get().uri("/custom").retrieve().toEntity(String.class).block();
+            } else if (client == Client.REST_CLIENT) {
+                restClient.get().uri("/custom").retrieve().toEntity(String.class);
             }
             throw new IllegalStateException(ILLEGAL_STATE_MESSAGE_PREFIX + client);
         } catch (CustomProblem e) {
@@ -120,6 +136,8 @@ public void unmappedFromBackend(@RequestParam("client") Client client) {
                 restTemplate.getForObject("/unmapped", String.class);
             } else if (client == Client.WEB_CLIENT) {
                 webClient.get().uri("/unmapped").retrieve().toEntity(String.class).block();
+            } else if (client == Client.REST_CLIENT) {
+                restClient.get().uri("/unmapped").retrieve().toEntity(String.class);
             }
             throw new IllegalStateException(ILLEGAL_STATE_MESSAGE_PREFIX + client);
         } catch (DefaultProblem e) {

belgif-rest-problem-spring-boot-3/pom.xml

@@ -46,6 +46,11 @@
       <artifactId>spring-webmvc</artifactId>
       <scope>provided</scope>
     </dependency>
+    <dependency>
+      <groupId>com.fasterxml.jackson.core</groupId>
+      <artifactId>jackson-databind</artifactId>
+      <scope>provided</scope>
+    </dependency>
     <dependency>
       <groupId>jakarta.platform</groupId>
       <artifactId>jakarta.jakartaee-api</artifactId>

belgif-rest-problem-spring-boot-3/src/main/java/io/github/belgif/rest/problem/spring/ProblemRestClientCustomizer.java

@@ -0,0 +1,26 @@
+package io.github.belgif.rest.problem.spring;
+
+import org.springframework.boot.web.client.RestClientCustomizer;
+import org.springframework.stereotype.Component;
+import org.springframework.web.client.RestClient;
+
+/**
+ * RestClientCustomizer that registers the {@link ProblemResponseErrorHandler}.
+ *
+ * @see ProblemResponseErrorHandler
+ */
+@Component
+public class ProblemRestClientCustomizer implements RestClientCustomizer {
+
+    private final ProblemResponseErrorHandler errorHandler;
+
+    public ProblemRestClientCustomizer(ProblemResponseErrorHandler errorHandler) {
+        this.errorHandler = errorHandler;
+    }
+
+    @Override
+    public void customize(RestClient.Builder restClientBuilder) {
+        restClientBuilder.defaultStatusHandler(errorHandler);
+    }
+
+}

belgif-rest-problem-spring-boot-3/src/test/java/io/github/belgif/rest/problem/spring/ProblemRestClientCustomizerTest.java

@@ -0,0 +1,26 @@
+package io.github.belgif.rest.problem.spring;
+
+import static org.assertj.core.api.Assertions.*;
+
+import java.util.List;
+
+import org.junit.jupiter.api.Test;
+import org.springframework.test.util.ReflectionTestUtils;
+import org.springframework.web.client.RestClient;
+
+import com.fasterxml.jackson.databind.ObjectMapper;
+
+class ProblemRestClientCustomizerTest {
+
+    @Test
+    void customize() {
+        ProblemResponseErrorHandler handler = new ProblemResponseErrorHandler(new ObjectMapper());
+        ProblemRestClientCustomizer customizer = new ProblemRestClientCustomizer(handler);
+        RestClient.Builder builder = RestClient.builder();
+        customizer.customize(builder);
+
+        List<?> statusHandlers = (List<?>) ReflectionTestUtils.getField(builder, "statusHandlers");
+        assertThat(statusHandlers).hasSize(1);
+    }
+
+}

src/main/asciidoc/index.adoc

@@ -39,6 +39,7 @@ To benefit from Spring Boot 2.x or 3.x specific features, replace dependencies t
 *belgif-rest-problem-spring-boot-3:*
 
 * Map NoResourceFoundException to 404 `urn:problem-type:belgif:resourceNotFound`
+* Added support for https://docs.spring.io/spring-framework/reference/integration/rest-clients.html#rest-restclient[RestClient] API
 
 === Version 0.4
 
@@ -348,7 +349,7 @@ io.github.belgif.rest.problem.scan-additional-problem-packages=com.acme.custom
 * *BeanValidationExceptionsHandler:* an exception handler for RestControllers that converts bean validation related exceptions to HTTP 400 BadRequestProblem.
 * *RoutingExceptionsHandler:* an exception handler for RestControllers that converts routing related validation exceptions to HTTP 400 BadRequestProblem.
 * *ProblemResponseErrorHandler:* a RestTemplate error handler that converts problem responses to Problem exceptions.
-* *ProblemRestTemplateCustomizer:* a RestTemplateCustomizer that registers the ProblemResponseErrorHandler
+* *ProblemRestTemplateCustomizer:* a RestTemplateCustomizer that registers the ProblemResponseErrorHandler.
 * *ProblemWebClientCustomizer:* a WebClientCustomizer that registers a filter that converts problem responses to Problem exceptions.
 This handles integration with the https://docs.spring.io/spring-framework/reference/web/webflux-webclient.html[Reactive WebClient].
 
@@ -365,6 +366,7 @@ Rather than depending on <<belgif-rest-problem-spring>> directly, Spring Boot 2.
 Rather than depending on <<belgif-rest-problem-spring>> directly, Spring Boot 3.x users are recommended to depend on `belgif-rest-problem-spring-boot-3`, which adds some Spring Boot 3.x specific integrations:
 
 * *NoResourceFoundExceptionHandler:* an exception handler for RestControllers that converts NoResourceFoundException to HTTP 404 ResourceNotFoundProblem.
+* *ProblemRestClientCustomizer:* a RestClientCustomizer that registers the ProblemResponseErrorHandler.
 
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