BAEL-9457: Implement handler interceptor for log body

spring-boot-modules/spring-boot-mvc-5/src/main/java/com/baeldung/httplogging/BookController.java

@@ -0,0 +1,26 @@
+package com.baeldung.httplogging;
+
+import org.springframework.http.HttpStatus;
+import org.springframework.http.ResponseEntity;
+import org.springframework.web.bind.annotation.PostMapping;
+import org.springframework.web.bind.annotation.RequestBody;
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RestController;
+
+import java.util.UUID;
+
+@RestController
+@RequestMapping("/api/books")
+public class BookController {
+
+    @PostMapping
+    public ResponseEntity<BookCreatedResponse> create(@RequestBody CreateBookRequest request) {
+        BookCreatedResponse response = new BookCreatedResponse(
+                UUID.randomUUID(),
+                request.title(),
+                request.author()
+        );
+
+        return ResponseEntity.status(HttpStatus.CREATED).body(response);
+    }
+}

spring-boot-modules/spring-boot-mvc-5/src/main/java/com/baeldung/httplogging/BookCreatedResponse.java

@@ -0,0 +1,5 @@
+package com.baeldung.httplogging;
+
+import java.util.UUID;
+
+public record BookCreatedResponse(UUID id, String title, String author) { }

spring-boot-modules/spring-boot-mvc-5/src/main/java/com/baeldung/httplogging/CachingHttpFilter.java

@@ -0,0 +1,35 @@
+package com.baeldung.httplogging;
+
+import jakarta.servlet.FilterChain;
+import jakarta.servlet.ServletException;
+import jakarta.servlet.http.HttpServletRequest;
+import jakarta.servlet.http.HttpServletResponse;
+import org.springframework.stereotype.Component;
+import org.springframework.web.filter.OncePerRequestFilter;
+import org.springframework.web.util.ContentCachingRequestWrapper;
+import org.springframework.web.util.ContentCachingResponseWrapper;
+
+import java.io.IOException;
+
+@Component
+public class CachingHttpFilter extends OncePerRequestFilter {
+
+    @Override
+    protected void doFilterInternal(
+            HttpServletRequest request,
+            HttpServletResponse response,
+            FilterChain filterChain) throws ServletException, IOException {
+
+        ContentCachingRequestWrapper cachingRequest =
+                new ContentCachingRequestWrapper(request);
+
+        ContentCachingResponseWrapper cachingResponse =
+                new ContentCachingResponseWrapper(response);
+
+        try {
+            filterChain.doFilter(cachingRequest, cachingResponse);
+        } finally {
+            cachingResponse.copyBodyToResponse();
+        }
+    }
+}

spring-boot-modules/spring-boot-mvc-5/src/main/java/com/baeldung/httplogging/CreateBookRequest.java

@@ -0,0 +1,3 @@
+package com.baeldung.httplogging;
+
+public record CreateBookRequest(String title, String author) { }

spring-boot-modules/spring-boot-mvc-5/src/main/java/com/baeldung/httplogging/HttpLoggingApplication.java

@@ -0,0 +1,12 @@
+package com.baeldung.httplogging;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+
+@SpringBootApplication
+public class HttpLoggingApplication {
+
+    public static void main(String[] args) {
+        SpringApplication.run(HttpLoggingApplication.class, args);
+    }
+}

spring-boot-modules/spring-boot-mvc-5/src/main/java/com/baeldung/httplogging/HttpLoggingInterceptor.java

@@ -0,0 +1,79 @@
+package com.baeldung.httplogging;
+
+import jakarta.servlet.http.HttpServletRequest;
+import jakarta.servlet.http.HttpServletResponse;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.stereotype.Component;
+import org.springframework.web.servlet.HandlerInterceptor;
+import org.springframework.web.util.ContentCachingRequestWrapper;
+import org.springframework.web.util.ContentCachingResponseWrapper;
+
+import java.io.UnsupportedEncodingException;
+import java.nio.charset.StandardCharsets;
+
+@Component
+public class HttpLoggingInterceptor implements HandlerInterceptor {
+
+    private static final Logger log =
+            LoggerFactory.getLogger(HttpLoggingInterceptor.class);
+
+    @Override
+    public boolean preHandle(
+            HttpServletRequest request,
+            HttpServletResponse response,
+            Object handler) {
+
+        log.info("Incoming {} {}", request.getMethod(), request.getRequestURI());
+        return true;
+    }
+
+    @Override
+    public void afterCompletion(
+            HttpServletRequest request,
+            HttpServletResponse response,
+            Object handler,
+            Exception ex) {
+
+        String requestBody = extractRequestBody(request);
+        String responseBody = extractResponseBody(response);
+
+        log.info(
+                "HTTP {} {} status={} requestBody={} responseBody={}",
+                request.getMethod(),
+                request.getRequestURI(),
+                response.getStatus(),
+                requestBody,
+                responseBody
+        );
+    }
+
+    private String extractRequestBody(HttpServletRequest request) {
+        if (request instanceof ContentCachingRequestWrapper wrapper) {
+            byte[] buf = wrapper.getContentAsByteArray();
+            var encoding = request.getCharacterEncoding();
+            return getStringValueFromBuffer(buf, encoding);
+        }
+        return "";
+    }
+
+    private String extractResponseBody(HttpServletResponse response) {
+        if (response instanceof ContentCachingResponseWrapper wrapper) {
+            byte[] buf = wrapper.getContentAsByteArray();
+            var encoding = response.getCharacterEncoding();
+            return getStringValueFromBuffer(buf, encoding);
+        }
+        return "";
+    }
+
+    private String getStringValueFromBuffer(byte[] buffer, String encoding) {
+        if (buffer.length > 0) {
+            try {
+                return new String(buffer, encoding != null ? encoding : StandardCharsets.UTF_8.name());
+            } catch (UnsupportedEncodingException ex) {
+                return "[unknown-encoding]";
+            }
+        }
+        return "";
+    }
+}

spring-boot-modules/spring-boot-mvc-5/src/main/java/com/baeldung/httplogging/WebConfig.java

@@ -0,0 +1,21 @@
+package com.baeldung.httplogging;
+
+import org.springframework.context.annotation.Configuration;
+import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
+import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;
+
+@Configuration
+public class WebConfig implements WebMvcConfigurer {
+
+    private final HttpLoggingInterceptor loggingInterceptor;
+
+    public WebConfig(HttpLoggingInterceptor loggingInterceptor) {
+        this.loggingInterceptor = loggingInterceptor;
+    }
+
+    @Override
+    public void addInterceptors(InterceptorRegistry registry) {
+        registry.addInterceptor(loggingInterceptor)
+                .addPathPatterns("/api/**");
+    }
+}

spring-boot-modules/spring-boot-mvc-5/src/test/java/com/baeldung/httplogging/BookControllerLoggingTest.java

@@ -0,0 +1,41 @@
+package com.baeldung.httplogging;
+
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.autoconfigure.web.servlet.AutoConfigureMockMvc;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.boot.test.system.CapturedOutput;
+import org.springframework.boot.test.system.OutputCaptureExtension;
+import org.springframework.http.MediaType;
+import org.springframework.test.web.servlet.MockMvc;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.post;
+import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.status;
+
+@SpringBootTest
+@AutoConfigureMockMvc
+@ExtendWith(OutputCaptureExtension.class)
+class BookControllerLoggingTest {
+
+    @Autowired
+    private MockMvc mockMvc;
+
+    @Test
+    void whenCreateBook_thenRequestAndResponseAreLogged(CapturedOutput output) throws Exception {
+        String requestBody = """
+                { "title": "Spring in Action", "author": "Craig Walls" }
+                """;
+
+        mockMvc.perform(post("/api/books")
+                        .contentType(MediaType.APPLICATION_JSON)
+                        .content(requestBody))
+                .andExpect(status().isCreated());
+
+        assertThat(output).contains("Incoming POST /api/books");
+        assertThat(output).contains("HTTP POST /api/books status=201");
+        assertThat(output).contains("\"title\":\"Spring in Action\"");
+        assertThat(output).contains("\"author\":\"Craig Walls\"");
+    }
+}