Falcon integration

README.rst

@@ -206,6 +206,48 @@ You can use DjangoOpenAPIResponse as a Django response factory:
    validator = ResponseValidator(spec)
    result = validator.validate(openapi_request, openapi_response)
 
+Falcon
+******
+
+This section describes integration with `Falcon <https://falconframework.org>`__ web framework.
+
+Middleware
+==========
+
+Falcon API can be integrated by `FalconOpenAPIMiddleware` middleware.
+
+.. code-block:: python
+
+   from openapi_core.contrib.falcon.middlewares import FalconOpenAPIMiddleware
+
+   openapi_middleware = FalconOpenAPIMiddleware.from_spec(spec)
+   api = falcon.API(middleware=[openapi_middleware])
+
+Low level
+=========
+
+For Falcon you can use FalconOpenAPIRequest a Falcon request factory:
+
+.. code-block:: python
+
+   from openapi_core.validation.request.validators import RequestValidator
+   from openapi_core.contrib.falcon import FalconOpenAPIRequest
+
+   openapi_request = FalconOpenAPIRequest(falcon_request)
+   validator = RequestValidator(spec)
+   result = validator.validate(openapi_request)
+
+You can use FalconOpenAPIResponse as a Falcon response factory:
+
+.. code-block:: python
+
+   from openapi_core.validation.response.validators import ResponseValidator
+   from openapi_core.contrib.falcon import FalconOpenAPIResponse
+
+   openapi_response = FalconOpenAPIResponse(falcon_response)
+   validator = ResponseValidator(spec)
+   result = validator.validate(openapi_request, openapi_response)
+
 Flask
 *****
 

openapi_core/contrib/falcon/__init__.py

@@ -0,0 +1,5 @@
+from openapi_core.contrib.falcon.requests import FalconOpenAPIRequestFactory
+from openapi_core.contrib.falcon.responses import FalconOpenAPIResponseFactory
+
+
+__all__ = ["FalconOpenAPIRequestFactory", "FalconOpenAPIResponseFactory"]

openapi_core/contrib/falcon/handlers.py

@@ -0,0 +1,52 @@
+"""OpenAPI core contrib falcon handlers module"""
+from json import dumps
+
+from falcon.constants import MEDIA_JSON
+from falcon.status_codes import (
+    HTTP_400, HTTP_404, HTTP_405, HTTP_415,
+)
+from openapi_core.schema.media_types.exceptions import InvalidContentType
+from openapi_core.templating.paths.exceptions import (
+    ServerNotFound, OperationNotFound, PathNotFound,
+)
+
+
+class FalconOpenAPIErrorsHandler(object):
+
+    OPENAPI_ERROR_STATUS = {
+        ServerNotFound: 400,
+        OperationNotFound: 405,
+        PathNotFound: 404,
+        InvalidContentType: 415,
+    }
+
+    FALCON_STATUS_CODES = {
+        400: HTTP_400,
+        404: HTTP_404,
+        405: HTTP_405,
+        415: HTTP_415,
+    }
+
+    @classmethod
+    def handle(cls, req, resp, errors):
+        data_errors = [
+            cls.format_openapi_error(err)
+            for err in errors
+        ]
+        data = {
+            'errors': data_errors,
+        }
+        data_error_max = max(data_errors, key=lambda x: x['status'])
+        resp.content_type = MEDIA_JSON
+        resp.status = cls.FALCON_STATUS_CODES.get(
+            data_error_max['status'], HTTP_400)
+        resp.body = dumps(data)
+        resp.complete = True
+
+    @classmethod
+    def format_openapi_error(cls, error):
+        return {
+            'title': str(error),
+            'status': cls.OPENAPI_ERROR_STATUS.get(error.__class__, 400),
+            'class': str(type(error)),
+        }

openapi_core/contrib/falcon/middlewares.py

@@ -0,0 +1,73 @@
+"""OpenAPI core contrib falcon middlewares module"""
+
+from openapi_core.contrib.falcon.handlers import FalconOpenAPIErrorsHandler
+from openapi_core.contrib.falcon.requests import FalconOpenAPIRequestFactory
+from openapi_core.contrib.falcon.responses import FalconOpenAPIResponseFactory
+from openapi_core.validation.processors import OpenAPIProcessor
+from openapi_core.validation.request.validators import RequestValidator
+from openapi_core.validation.response.validators import ResponseValidator
+
+
+class FalconOpenAPIMiddleware(OpenAPIProcessor):
+
+    def __init__(
+            self,
+            request_validator,
+            response_validator,
+            request_factory,
+            response_factory,
+            openapi_errors_handler,
+    ):
+        super(FalconOpenAPIMiddleware, self).__init__(
+            request_validator, response_validator)
+        self.request_factory = request_factory
+        self.response_factory = response_factory
+        self.openapi_errors_handler = openapi_errors_handler
+
+    def process_request(self, req, resp):
+        openapi_req = self._get_openapi_request(req)
+        req_result = super(FalconOpenAPIMiddleware, self).process_request(
+            openapi_req)
+        if req_result.errors:
+            return self._handle_request_errors(req, resp, req_result)
+        req.openapi = req_result
+
+    def process_response(self, req, resp, resource, req_succeeded):
+        openapi_req = self._get_openapi_request(req)
+        openapi_resp = self._get_openapi_response(resp)
+        resp_result = super(FalconOpenAPIMiddleware, self).process_response(
+            openapi_req, openapi_resp)
+        if resp_result.errors:
+            return self._handle_response_errors(req, resp, resp_result)
+
+    def _handle_request_errors(self, req, resp, request_result):
+        return self.openapi_errors_handler.handle(
+            req, resp, request_result.errors)
+
+    def _handle_response_errors(self, req, resp, response_result):
+        return self.openapi_errors_handler.handle(
+            req, resp, response_result.errors)
+
+    def _get_openapi_request(self, request):
+        return self.request_factory.create(request)
+
+    def _get_openapi_response(self, response):
+        return self.response_factory.create(response)
+
+    @classmethod
+    def from_spec(
+            cls,
+            spec,
+            request_factory=FalconOpenAPIRequestFactory,
+            response_factory=FalconOpenAPIResponseFactory,
+            openapi_errors_handler=FalconOpenAPIErrorsHandler,
+    ):
+        request_validator = RequestValidator(spec)
+        response_validator = ResponseValidator(spec)
+        return cls(
+            request_validator=request_validator,
+            response_validator=response_validator,
+            request_factory=request_factory,
+            response_factory=response_factory,
+            openapi_errors_handler=openapi_errors_handler,
+        )

openapi_core/contrib/falcon/requests.py

@@ -0,0 +1,45 @@
+"""OpenAPI core contrib falcon responses module"""
+from json import dumps
+
+from werkzeug.datastructures import ImmutableMultiDict
+
+from openapi_core.validation.request.datatypes import (
+    OpenAPIRequest, RequestParameters,
+)
+
+
+class FalconOpenAPIRequestFactory:
+
+    @classmethod
+    def create(cls, request):
+        """
+        Create OpenAPIRequest from falcon Request and route params.
+        """
+        method = request.method.lower()
+
+        # gets deduced by path finder against spec
+        path = {}
+
+        # Support falcon-jsonify.
+        body = (
+            dumps(request.json) if getattr(request, "json", None)
+            else request.bounded_stream.read()
+        )
+        mimetype = request.options.default_media_type
+        if request.content_type:
+            mimetype = request.content_type.partition(";")[0]
+
+        query = ImmutableMultiDict(request.params.items())
+        parameters = RequestParameters(
+            query=query,
+            header=request.headers,
+            cookie=request.cookies,
+            path=path,
+        )
+        return OpenAPIRequest(
+            full_url_pattern=request.url,
+            method=method,
+            parameters=parameters,
+            body=body,
+            mimetype=mimetype,
+        )

openapi_core/contrib/falcon/responses.py

@@ -0,0 +1,20 @@
+"""OpenAPI core contrib falcon responses module"""
+from openapi_core.validation.response.datatypes import OpenAPIResponse
+
+
+class FalconOpenAPIResponseFactory(object):
+    @classmethod
+    def create(cls, response):
+        status_code = int(response.status[:3])
+
+        mimetype = ''
+        if response.content_type:
+            mimetype = response.content_type.partition(";")[0]
+        else:
+            mimetype = response.options.default_media_type
+
+        return OpenAPIResponse(
+            data=response.body,
+            status_code=status_code,
+            mimetype=mimetype,
+        )

requirements_dev.txt

@@ -2,6 +2,7 @@ mock==2.0.0
 pytest==3.5.0
 pytest-flake8
 pytest-cov==2.5.1
+falcon==2.0.0
 flask
 django==2.2.10; python_version>="3.0"
 requests==2.22.0

setup.cfg

@@ -38,6 +38,7 @@ tests_require =
     pytest
     pytest-flake8
     pytest-cov
+    falcon
     flask
     webob
 

tests/integration/contrib/falcon/conftest.py

@@ -0,0 +1,51 @@
+from falcon import Request, Response, RequestOptions, ResponseOptions
+from falcon.routing import DefaultRouter
+from falcon.status_codes import HTTP_200
+from falcon.testing import create_environ
+import pytest
+
+
+@pytest.fixture
+def environ_factory():
+    def create_env(method, path, server_name):
+        return create_environ(
+            host=server_name,
+            path=path,
+        )
+    return create_env
+
+
+@pytest.fixture
+def router():
+    router = DefaultRouter()
+    router.add_route("/browse/{id:int}/", lambda x: x)
+    return router
+
+
+@pytest.fixture
+def request_factory(environ_factory, router):
+    server_name = 'localhost'
+
+    def create_request(
+            method, path, subdomain=None, query_string=None,
+            content_type='application/json'):
+        environ = environ_factory(method, path, server_name)
+        options = RequestOptions()
+        # return create_req(options=options, **environ)
+        req = Request(environ, options)
+        resource, method_map, params, req.uri_template = router.find(path, req)
+        return req
+    return create_request
+
+
+@pytest.fixture
+def response_factory(environ_factory):
+    def create_response(
+            data, status_code=200, content_type='application/json'):
+        options = ResponseOptions()
+        resp = Response(options)
+        resp.body = data
+        resp.content_type = content_type
+        resp.status = HTTP_200
+        return resp
+    return create_response

tests/integration/contrib/falcon/data/v3.0/falcon_factory.yaml

@@ -0,0 +1,48 @@
+openapi: "3.0.0"
+info:
+  title: Basic OpenAPI specification used with test_falcon.TestFalconOpenAPIIValidation
+  version: "0.1"
+servers:
+  - url: 'http://localhost'
+paths:
+  '/browse/{id}':
+    parameters:
+      - name: id
+        in: path
+        required: true
+        description: the ID of the resource to retrieve
+        schema:
+          type: integer
+    get:
+      responses:
+        200:
+          description: Return the resource.
+          content:
+            application/json:    
+              schema:
+                type: object
+                required:
+                  - data
+                properties:
+                  data:
+                    type: string
+        default:
+          description: Return errors.
+          content:
+            application/json:
+              schema:
+                type: object
+                required:
+                  - errors
+                properties:
+                  errors:
+                    type: array
+                    items:
+                      type: object
+                      properties:
+                        title:
+                          type: string
+                        code:
+                          type: string
+                        message:
+                          type: string