Maps all unique content-types for operations and set passthroughBehavior to never in CORS preflight integration

docs/source-2.0/guides/model-translations/converting-to-openapi.rst

@@ -1550,6 +1550,29 @@ additionalAllowedCorsHeaders (``[string]``)
             }
         }
 
+
+.. _generate-openapi-apigateway-setting-syncCorsPreflightIntegration:
+
+syncCorsPreflightIntegration (``boolean``)
+    Set to true to sync CORS preflight integration request templates with all possible content-types
+    from other methods within the same path resource.
+
+    .. code-block:: json
+        :caption: smithy-build.json
+
+        {
+            "version": "1.0",
+            "plugins": {
+                "openapi": {
+                    "service": "example.weather#Weather",
+                    "syncCorsPreflightIntegration": true
+                }
+            }
+        }
+
+    With this enabled, the `integration's passthroughBehavior`_ for CORS preflight integration
+    will be set to ``never``.
+
 Binary types
 ============
 
@@ -1648,6 +1671,10 @@ additions during the OpenAPI conversion:
 * Adds static CORS response headers to API Gateway "gateway" responses.  These are added only when
   no gateway responses are defined in the OpenAPI model.
 
+.. note::
+    If :ref:`syncCorsPreflightIntegration <generate-openapi-apigateway-setting-syncCorsPreflightIntegration>` is
+    set to ``true``, the CORS preflight `integration's passthroughBehavior`_ will be set to ``never`` and the integration's
+    request templates will be synced with all possible content-types from other methods within the same path resource.
 
 .. _authorizers:
 
@@ -2037,4 +2064,5 @@ The conversion process is highly extensible through
 .. _Lambda authorizers: https://docs.aws.amazon.com/apigateway/latest/developerguide/api-gateway-swagger-extensions-authorizer.html
 .. _API Gateway's API key usage plans: https://docs.aws.amazon.com/apigateway/latest/developerguide/api-gateway-api-usage-plans.html
 .. _OpenAPI specification extension: https://spec.openapis.org/oas/v3.1.0#specification-extensions
+.. _integration's passthroughBehavior: https://docs.aws.amazon.com/apigateway/latest/developerguide/integration-passthrough-behaviors.html
 .. _gradle installed: https://gradle.org/install/

smithy-aws-apigateway-openapi/src/main/java/software/amazon/smithy/aws/apigateway/openapi/AddCorsPreflightIntegration.java

@@ -31,6 +31,7 @@
 import software.amazon.smithy.jsonschema.Schema;
 import software.amazon.smithy.model.Model;
 import software.amazon.smithy.model.knowledge.TopDownIndex;
+import software.amazon.smithy.model.node.Node;
 import software.amazon.smithy.model.node.ObjectNode;
 import software.amazon.smithy.model.shapes.OperationShape;
 import software.amazon.smithy.model.traits.CorsTrait;
@@ -45,6 +46,7 @@
 import software.amazon.smithy.openapi.model.ResponseObject;
 import software.amazon.smithy.utils.CaseUtils;
 import software.amazon.smithy.utils.ListUtils;
+import software.amazon.smithy.utils.SetUtils;
 
 /**
  * Adds CORS-preflight OPTIONS requests using mock API Gateway integrations.
@@ -70,6 +72,7 @@ final class AddCorsPreflightIntegration implements ApiGatewayMapper {
     private static final Logger LOGGER = Logger.getLogger(AddCorsPreflightIntegration.class.getName());
     private static final String API_GATEWAY_DEFAULT_ACCEPT_VALUE = "application/json";
     private static final String INTEGRATION_EXTENSION = "x-amazon-apigateway-integration";
+    private static final String REQUEST_TEMPLATES_KEY = "requestTemplates";
     private static final String PREFLIGHT_SUCCESS = "{\"statusCode\":200}";
 
     @Override
@@ -95,7 +98,7 @@ private static PathItem addPreflightIntegration(
         LOGGER.fine(() -> "Adding CORS-preflight OPTIONS request and API Gateway integration for " + path);
         Map<CorsHeader, String> headers = deduceCorsHeaders(context, path, pathItem, corsTrait);
         return pathItem.toBuilder()
-                .options(createPreflightOperation(path, pathItem, headers))
+                .options(createPreflightOperation(context, path, pathItem, headers))
                 .build();
     }
 
@@ -170,15 +173,15 @@ private static String getAllowMethods(PathItem item) {
     }
 
     private static OperationObject createPreflightOperation(
-            String path, PathItem pathItem, Map<CorsHeader, String> headers) {
+            Context<? extends Trait> context, String path, PathItem pathItem, Map<CorsHeader, String> headers) {
         return OperationObject.builder()
                 .tags(ListUtils.of("CORS"))
                 .security(Collections.emptyList())
                 .description("Handles CORS-preflight requests")
                 .operationId(createOperationId(path))
                 .putResponse("200", createPreflightResponse(headers))
                 .parameters(findPathParameters(pathItem))
-                .putExtension(INTEGRATION_EXTENSION, createPreflightIntegration(headers, pathItem))
+                .putExtension(INTEGRATION_EXTENSION, createPreflightIntegration(context, headers, pathItem))
                 .build();
     }
 
@@ -214,21 +217,43 @@ private static ResponseObject createPreflightResponse(Map<CorsHeader, String> he
         return builder.build();
     }
 
-    private static ObjectNode createPreflightIntegration(Map<CorsHeader, String> headers, PathItem pathItem) {
+    private static ObjectNode createPreflightIntegration(
+            Context<? extends Trait> context, Map<CorsHeader, String> headers, PathItem pathItem) {
         IntegrationResponse.Builder responseBuilder = IntegrationResponse.builder().statusCode("200");
 
         // Add each CORS header to the mock integration response.
         for (Map.Entry<CorsHeader, String> e : headers.entrySet()) {
             responseBuilder.putResponseParameter("method.response.header." + e.getKey(), "'" + e.getValue() + "'");
         }
 
+        boolean isPreflightSynced = Boolean.TRUE.equals(context.getConfig().getSyncCorsPreflightIntegration());
         MockIntegrationTrait.Builder integration = MockIntegrationTrait.builder()
                 // See https://forums.aws.amazon.com/thread.jspa?threadID=256140
                 .contentHandling("CONVERT_TO_TEXT")
-                .passThroughBehavior("when_no_match")
+                // Passthrough behavior "never" will fail the request with unsupported content type more appropriately.
+                // https://docs.aws.amazon.com/apigateway/latest/developerguide/integration-passthrough-behaviors.html
+                .passThroughBehavior(isPreflightSynced ? "never" : "when_no_match")
                 .putResponse("default", responseBuilder.build())
                 .putRequestTemplate(API_GATEWAY_DEFAULT_ACCEPT_VALUE, PREFLIGHT_SUCCESS);
 
+        if (isPreflightSynced) {
+            // Adds request template for every unique Content-Type supported by all path operations.
+            // This ensures that for Content-Type(s) other than 'application/json', the entire request payload
+            // is not sent to APIGW mock integration as stipulated by 'when_no_match' passthroughBehavior.
+            // APIGW throws an error if the mock integration request does not follow a set contract,
+            // example {"statusCode":200}.
+            for (OperationObject operation : pathItem.getOperations().values()) {
+                ObjectNode extensionNode = operation.getExtension(INTEGRATION_EXTENSION)
+                        .flatMap(Node::asObjectNode)
+                        .orElse(Node.objectNode());
+                Set<String> mimeTypes = extensionNode.getObjectMember(REQUEST_TEMPLATES_KEY)
+                        .map(ObjectNode::getStringMap)
+                        .map(Map::keySet)
+                        .orElse(SetUtils.of());
+                mimeTypes.forEach(mimeType -> integration.putRequestTemplate(mimeType, PREFLIGHT_SUCCESS));
+            }
+        }
+
         // Add a request template for every mime-type of every response.
         for (OperationObject operation : pathItem.getOperations().values()) {
             for (ResponseObject response : operation.getResponses().values()) {

smithy-aws-apigateway-openapi/src/test/java/software/amazon/smithy/aws/apigateway/openapi/CorsTest.java

@@ -112,4 +112,37 @@ public OpenApi after(Context context, OpenApi openapi) {
 
         Node.assertEquals(result, expectedNode);
     }
+
+    @Test
+    public void withPreflightIntegrationSync() {
+        Model model = Model.assembler(getClass().getClassLoader())
+                .discoverModels(getClass().getClassLoader())
+                .addImport(getClass().getResource("cors-with-multi-request-templates.json"))
+                .assemble()
+                .unwrap();
+        OpenApiConfig config = new OpenApiConfig();
+        config.setService(ShapeId.from("example.smithy#MyService"));
+        config.setSyncCorsPreflightIntegration(true);
+        ObjectNode result = OpenApiConverter.create().config(config).convertToNode(model);
+        Node expectedNode = Node.parse(IoUtils.toUtf8String(
+                getClass().getResourceAsStream("cors-with-preflight-sync.openapi.json")));
+
+        Node.assertEquals(result, expectedNode);
+    }
+
+    @Test
+    public void withoutPreflightIntegrationSync() {
+        Model model = Model.assembler(getClass().getClassLoader())
+                .discoverModels(getClass().getClassLoader())
+                .addImport(getClass().getResource("cors-with-multi-request-templates.json"))
+                .assemble()
+                .unwrap();
+        OpenApiConfig config = new OpenApiConfig();
+        config.setService(ShapeId.from("example.smithy#MyService"));
+        ObjectNode result = OpenApiConverter.create().config(config).convertToNode(model);
+        Node expectedNode = Node.parse(IoUtils.toUtf8String(
+                getClass().getResourceAsStream("cors-without-preflight-sync.openapi.json")));
+
+        Node.assertEquals(result, expectedNode);
+    }
 }

smithy-aws-apigateway-openapi/src/test/resources/software/amazon/smithy/aws/apigateway/openapi/cors-with-multi-request-templates.json

@@ -0,0 +1,102 @@
+{
+    "smithy": "2.0",
+    "shapes": {
+        "example.smithy#MyService": {
+            "type": "service",
+            "version": "2006-03-01",
+            "operations": [
+                {
+                    "target": "example.smithy#MockPut"
+                },
+                {
+                    "target": "example.smithy#MockGet"
+                }
+            ],
+            "traits": {
+                "aws.protocols#restJson1": {},
+                "aws.auth#sigv4": {
+                    "name": "myservice"
+                },
+                "smithy.api#cors": {
+                    "origin": "https://www.example.com",
+                    "maxAge": 86400,
+                    "additionalAllowedHeaders": [
+                        "X-Service-Input-Metadata"
+                    ],
+                    "additionalExposedHeaders": [
+                        "X-Service-Output-Metadata"
+                    ]
+                }
+            }
+        },
+        "example.smithy#MockGet": {
+            "type": "operation",
+            "output": {
+                "target": "example.smithy#MockOutput"
+            },
+            "traits": {
+                "aws.apigateway#mockIntegration": {
+                    "passThroughBehavior": "never",
+                    "requestTemplates": {
+                        "application/json": "{\"statusCode\": 200}",
+                        "application/x-www-form-urlencoded": "{\"statusCode\": 200}"
+                    },
+                    "responses": {
+                        "default": {
+                            "statusCode": "200",
+                            "responseTemplates": {
+                                "application/json": "{\"extendedRequestId\": \"$context.extendedRequestId\"}"
+                            }
+                        }
+                    }
+                },
+                "smithy.api#http": {
+                    "code": 200,
+                    "method": "GET",
+                    "uri": "/mock"
+                },
+                "smithy.api#readonly": {}
+            }
+        },
+        "example.smithy#MockPut": {
+            "type": "operation",
+            "output": {
+                "target": "example.smithy#MockOutput"
+            },
+            "traits": {
+                "aws.apigateway#mockIntegration": {
+                    "passThroughBehavior": "never",
+                    "requestTemplates": {
+                        "text/plain": "{\"statusCode\": 200}",
+                        "application/xml": "{\"statusCode\": 200}"
+                    },
+                    "responses": {
+                        "default": {
+                            "statusCode": "200",
+                            "responseTemplates": {
+                                "application/json": "{\"extendedRequestId\": \"$context.extendedRequestId\"}"
+                            }
+                        }
+                    }
+                },
+                "smithy.api#http": {
+                    "code": 201,
+                    "method": "PUT",
+                    "uri": "/mock"
+                },
+                "smithy.api#idempotent": {}
+            }
+        },
+        "example.smithy#MockOutput": {
+            "type": "structure",
+            "members": {
+                "extendedRequestId": {
+                    "target": "smithy.api#String",
+                    "traits": {
+                        "smithy.api#required": {}
+                    }
+                }
+            }
+        }
+    }
+}