Add inspector for the Body request parameter

README.md

@@ -108,15 +108,16 @@ Take in account that you need to use **Java 11 or greater**.
 
 We have the following attributes to create a CleverClient object:
 
-| Attribute          | Description                                      | Required  |
-| -------------------|--------------------------------------------------|-----------|
-| baseUrl            | Api's url                                        | mandatory |
-| headers            | Map of headers (name/value)                      | optional  |
-| header             | Single header as a name and a value              | optional  |
-| httpClient         | Java HttpClient object                           | optional  |
-| requestInterceptor | Function to modify the request once is built     | optional  |
-| endsOfStream       | List of texts used to mark the end of streams    | optional  |
-| endOfStream        | Text used to mark the end of streams             | optional  |
+| Attribute          | Description                                       | Required  |
+| -------------------|---------------------------------------------------|-----------|
+| baseUrl            | Api's url                                         | mandatory |
+| headers            | Map of headers (name/value)                       | optional  |
+| header             | Single header as a name and a value               | optional  |
+| httpClient         | Java HttpClient object                            | optional  |
+| requestInterceptor | Function to modify the request once is built      | optional  |
+| bodyInspector      | Function to inspect the `@Body` request parameter | optional  |
+| endsOfStream       | List of texts used to mark the end of streams     | optional  |
+| endOfStream        | Text used to mark the end of streams              | optional  |
 
 The attribute ```end(s)OfStream``` is required when you have endpoints sending back streams of data (Server Sent Events - SSE).
 

src/main/java/io/github/sashirestela/cleverclient/CleverClient.java

@@ -16,6 +16,7 @@
 import java.util.List;
 import java.util.Map;
 import java.util.Optional;
+import java.util.function.Consumer;
 import java.util.function.UnaryOperator;
 
 /**
@@ -31,6 +32,7 @@ public class CleverClient {
     private final Map<String, String> headers;
     private final HttpClient httpClient;
     private final UnaryOperator<HttpRequestData> requestInterceptor;
+    private final Consumer<Object> bodyInspector;
     private final HttpProcessor httpProcessor;
 
     /**
@@ -41,21 +43,25 @@ public class CleverClient {
      * @param httpClient         Custom Java's HttpClient component. One is created by default if none
      *                           is passed. Optional.
      * @param requestInterceptor Function to modify the request once it has been built.
+     * @param bodyInspector      Function to inspect the Body request parameter.
      * @param endsOfStream       Texts used to mark the final of streams when handling server sent
      *                           events (SSE). Optional.
      */
     @Builder
     public CleverClient(@NonNull String baseUrl, @Singular Map<String, String> headers, HttpClient httpClient,
-            UnaryOperator<HttpRequestData> requestInterceptor, @Singular("endOfStream") List<String> endsOfStream) {
+            UnaryOperator<HttpRequestData> requestInterceptor, Consumer<Object> bodyInspector,
+            @Singular("endOfStream") List<String> endsOfStream) {
         this.baseUrl = baseUrl;
         this.headers = Optional.ofNullable(headers).orElse(Map.of());
         this.httpClient = Optional.ofNullable(httpClient).orElse(HttpClient.newHttpClient());
         this.requestInterceptor = requestInterceptor;
+        this.bodyInspector = bodyInspector;
         this.httpProcessor = HttpProcessor.builder()
                 .baseUrl(this.baseUrl)
                 .headers(CommonUtil.mapToListOfString(this.headers))
                 .httpClient(this.httpClient)
                 .requestInterceptor(this.requestInterceptor)
+                .bodyInspector(bodyInspector)
                 .build();
         Configurator.builder()
                 .endsOfStream(Optional.ofNullable(endsOfStream).orElse(Arrays.asList()))

src/main/java/io/github/sashirestela/cleverclient/http/HttpProcessor.java

@@ -16,6 +16,7 @@
 import java.net.http.HttpClient;
 import java.util.ArrayList;
 import java.util.List;
+import java.util.function.Consumer;
 import java.util.function.UnaryOperator;
 
 /**
@@ -30,6 +31,7 @@ public class HttpProcessor implements InvocationHandler {
     private final List<String> headers;
     private final HttpClient httpClient;
     private final UnaryOperator<HttpRequestData> requestInterceptor;
+    private final Consumer<Object> bodyInspector;
 
     /**
      * Creates a generic dynamic proxy with this HttpProcessor object acting as an InvocationHandler to
@@ -99,8 +101,9 @@ private Object resolve(Method method, Object[] arguments) {
         var url = baseUrl + URLBuilder.one().build(urlMethod, methodMetadata, arguments);
         var httpMethod = methodMetadata.getHttpAnnotationName();
         var returnType = methodMetadata.getReturnType();
-        var bodyObject = calculateBodyObject(methodMetadata, arguments);
         var contentType = methodMetadata.getContentType();
+        var body = getAndInspectBody(methodMetadata, arguments);
+        var bodyObject = getBodyObject(body, contentType);
         var fullHeaders = new ArrayList<>(this.headers);
         fullHeaders.addAll(calculateHeaderContentType(contentType));
         fullHeaders.addAll(interfaceMetadata.getFullHeadersByMethod(methodMetadata));
@@ -117,14 +120,24 @@ private Object resolve(Method method, Object[] arguments) {
         return httpConnector.sendRequest();
     }
 
-    private Object calculateBodyObject(MethodMetadata methodMetadata, Object[] arguments) {
+    private Object getAndInspectBody(MethodMetadata methodMetadata, Object[] arguments) {
         var bodyIndex = methodMetadata.getBodyIndex();
-        var bodyObject = bodyIndex >= 0 ? arguments[bodyIndex] : null;
-        if (bodyObject != null) {
-            if (methodMetadata.getContentType() == ContentType.MULTIPART_FORMDATA) {
-                bodyObject = JsonUtil.objectToMap(bodyObject);
-            } else if (methodMetadata.getContentType() == ContentType.APPLICATION_JSON) {
-                bodyObject = JsonUtil.objectToJson(bodyObject);
+        var body = bodyIndex >= 0 ? arguments[bodyIndex] : null;
+
+        if (body != null && bodyInspector != null) {
+            bodyInspector.accept(body);
+        }
+
+        return body;
+    }
+
+    private Object getBodyObject(Object body, ContentType contentType) {
+        Object bodyObject = null;
+        if (body != null) {
+            if (contentType == ContentType.MULTIPART_FORMDATA) {
+                bodyObject = JsonUtil.objectToMap(body);
+            } else if (contentType == ContentType.APPLICATION_JSON) {
+                bodyObject = JsonUtil.objectToJson(body);
             }
         }
         return bodyObject;

src/test/java/io/github/sashirestela/cleverclient/CleverClientTest.java

@@ -17,8 +17,10 @@
 import java.net.http.HttpResponse;
 import java.util.Map;
 import java.util.concurrent.CompletableFuture;
+import java.util.function.Consumer;
 import java.util.function.UnaryOperator;
 
+import static org.junit.jupiter.api.Assertions.assertDoesNotThrow;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertNotNull;
 import static org.junit.jupiter.api.Assertions.assertNull;
@@ -41,6 +43,7 @@ void shouldSetPropertiesToDefaultValuesWhenBuilderIsCalledWithoutThoseProperties
         assertNotNull(cleverClient.getBaseUrl());
         assertNotNull(cleverClient.getHttpProcessor());
         assertNull(cleverClient.getRequestInterceptor());
+        assertNull(cleverClient.getBodyInspector());
     }
 
     @Test
@@ -122,6 +125,44 @@ void shouldModifyRequestWhenPassingInterceptorFunction() {
         assertEquals(expectedBody, actualBody);
     }
 
+    @SuppressWarnings("unchecked")
+    @Test
+    void shouldNotThrownExceptionWhenBodyInspectorEndsSuccessfully() {
+        var httpClient = mock(HttpClient.class);
+        Consumer<Object> bodyInspector = body -> {
+            var sample = (Sample) body;
+            if (sample.getModel() == null) {
+                throw new IllegalArgumentException("The parameter model must not be null.");
+            }
+        };
+        var cleverClient = CleverClient.builder()
+                .baseUrl("https://test")
+                .bodyInspector(bodyInspector)
+                .httpClient(httpClient)
+                .build();
+        when(httpClient.sendAsync(any(), any()))
+                .thenReturn(CompletableFuture.completedFuture(mock(HttpResponse.class)));
+        var testService = cleverClient.create(TestCleverClient.class);
+        assertDoesNotThrow(() -> testService.getText(Sample.builder().model("abc").build(), "math"));
+    }
+
+    @Test
+    void shouldThrownExceptionWhenBodyInspectorFails() {
+        Consumer<Object> bodyInspector = body -> {
+            var sample = (Sample) body;
+            if (sample.getModel() == null) {
+                throw new IllegalArgumentException("The parameter model must not be null.");
+            }
+        };
+        var cleverClient = CleverClient.builder()
+                .baseUrl("https://test")
+                .bodyInspector(bodyInspector)
+                .build();
+        var testService = cleverClient.create(TestCleverClient.class);
+        assertThrows(IllegalArgumentException.class,
+                () -> testService.getText(Sample.builder().build(), "math"));
+    }
+
     @Value
     @Builder
     static class Sample {