feat(core): expose request body named examples to templates

modules/openapi-generator/src/main/java/org/openapitools/codegen/DefaultCodegen.java

@@ -2456,6 +2456,18 @@ public void setParameterExamples(CodegenParameter codegenParameter, Parameter pa
         }
     }
 
+    /**
+     * Return the examples of the parameter.
+     *
+     * @param codegenParameter Codegen parameter
+     * @param mediaType        Media type
+     */
+    public void setParameterExamples(CodegenParameter codegenParameter, MediaType mediaType) {
+        if (mediaType.getExamples() != null && !mediaType.getExamples().isEmpty()) {
+            codegenParameter.examples = mediaType.getExamples();
+        }
+    }
+
     /**
      * Return the example value of the parameter.
      *
@@ -7442,13 +7454,33 @@ public void writePropertyBack(String propertyKey, Object value) {
     }
 
     protected String getContentType(RequestBody requestBody) {
-        if (requestBody == null || requestBody.getContent() == null || requestBody.getContent().isEmpty()) {
+        if (!hasMediaType(requestBody)) {
             LOGGER.debug("Cannot determine the content type. Returning null.");
             return null;
         }
         return new ArrayList<>(requestBody.getContent().keySet()).get(0);
     }
 
+    /**
+     *
+     * @param requestBody The request body
+     * @return The first media type of the request body's content, if it exists. Otherwise, returns an empty Optional.
+     */
+    private Optional<MediaType> getFirstContentMediaType(RequestBody requestBody) {
+        if (hasMediaType(requestBody)) {
+            return Optional.of(requestBody.getContent().values().iterator().next());
+        }
+        return Optional.empty();
+    }
+
+    private static boolean hasMediaType(RequestBody requestBody) {
+        return requestBody != null && requestBody.getContent() != null && !requestBody.getContent().isEmpty();
+    }
+
+    private static boolean hasMediaType(ApiResponse apiResponse) {
+        return apiResponse != null && apiResponse.getContent() != null && !apiResponse.getContent().isEmpty();
+    }
+
     private void setOauth2Info(CodegenSecurity codegenSecurity, OAuthFlow flow) {
         codegenSecurity.authorizationUrl = flow.getAuthorizationUrl();
         codegenSecurity.tokenUrl = flow.getTokenUrl();
@@ -7481,7 +7513,7 @@ private void setOpenIdConnectInfo(CodegenSecurity codegenSecurity, OAuthFlow flo
 
     private void addConsumesInfo(Operation operation, CodegenOperation codegenOperation) {
         RequestBody requestBody = ModelUtils.getReferencedRequestBody(this.openAPI, operation.getRequestBody());
-        if (requestBody == null || requestBody.getContent() == null || requestBody.getContent().isEmpty()) {
+        if (!hasMediaType(requestBody)) {
             return;
         }
 
@@ -7512,7 +7544,7 @@ private void addConsumesInfo(Operation operation, CodegenOperation codegenOperat
     public static Set<String> getConsumesInfo(OpenAPI openAPI, Operation operation) {
         RequestBody requestBody = ModelUtils.getReferencedRequestBody(openAPI, operation.getRequestBody());
 
-        if (requestBody == null || requestBody.getContent() == null || requestBody.getContent().isEmpty()) {
+        if (!hasMediaType(requestBody)) {
             return Collections.emptySet(); // return empty set
         }
         return requestBody.getContent().keySet();
@@ -7548,7 +7580,7 @@ public boolean hasBodyParameter(Operation operation) {
 
     private void addProducesInfo(ApiResponse inputResponse, CodegenOperation codegenOperation) {
         ApiResponse response = ModelUtils.getReferencedApiResponse(this.openAPI, inputResponse);
-        if (response == null || response.getContent() == null || response.getContent().isEmpty()) {
+        if (!hasMediaType(response)) {
             return;
         }
 
@@ -8376,6 +8408,9 @@ public CodegenParameter fromRequestBody(RequestBody body, Set<String> imports, S
         // should be overridden by lang codegen
         setParameterExampleValue(codegenParameter, body);
 
+        getFirstContentMediaType(body)
+                .ifPresent(mediaType -> setParameterExamples(codegenParameter, mediaType));
+
         // restore original schema with description, extensions etc
         if (original != null) {
             // evaluate common attributes such as description if defined in the top level

modules/openapi-generator/src/test/java/org/openapitools/codegen/DefaultCodegenTest.java

@@ -1156,6 +1156,26 @@ public void testExample5MultipleResponses() {
         assertEquals("500", examples.get(3).get("statusCode"));
     }
 
+    @Test
+    public void testExample6MultipleRequestBodyExamples() {
+        final OpenAPI openAPI = TestUtils.parseFlattenSpec("src/test/resources/3_0/examples.yaml");
+        final DefaultCodegen codegen = new DefaultCodegen();
+        codegen.setOpenAPI(openAPI);
+        String path = "/example6/multiple_examples";
+
+        Operation operation = openAPI.getPaths().get(path).getPost();
+        CodegenOperation codegenOperation = codegen.fromOperation(path, "POST", operation, null);
+        CodegenParameter bodyParam = codegenOperation.bodyParam;
+
+        assertEquals("An example6 value 1", bodyParam.example);
+
+        // verify all named examples are populated in the body parameter's examples
+        assertEquals(3, bodyParam.examples.size());
+        assertEquals("An example6 value 1", bodyParam.examples.get("FirstExample").getValue());
+        assertEquals("An example6 value 2", bodyParam.examples.get("SecondExample").getValue());
+        assertEquals("An example6 value 3", bodyParam.examples.get("ThirdExample").getValue());
+    }
+
     @Test
     public void testDiscriminator() {
         final OpenAPI openAPI = TestUtils.parseFlattenSpec("src/test/resources/2_0/petstore-with-fake-endpoints-models-for-testing.yaml");

modules/openapi-generator/src/test/resources/3_0/examples.yaml

@@ -139,6 +139,30 @@ paths:
               schema:
                 type: string
                 example: an internal server error response example
+  /example6/multiple_examples:
+    post:
+      operationId: example6PostMultipleExamples
+      requestBody:
+        content:
+          application/json:
+            schema:
+              type: object
+              properties:
+                name:
+                  type: string
+            examples:
+              FirstExample:
+                summary: The first example value
+                value: 'An example6 value 1'
+              SecondExample:
+                summary: The second example value
+                value: 'An example6 value 2'
+              ThirdExample:
+                summary: The third example value
+                value: 'An example6 value 3'
+      responses:
+        '200':
+          description: successful operation
 components:
   schemas:
     User: