FastAPI integration

Author: p1c2u

docs/integrations/fastapi.rst

@@ -0,0 +1,58 @@
+FastAPI
+=========
+
+This section describes integration with `FastAPI <https://fastapi.tiangolo.com>`__  ASGI framework.
+
+.. note::
+
+    FastAPI also provides OpenAPI support. The main difference is that, unlike FastAPI's code-first approach, OpenAPI-core allows you to laverage your existing specification that alligns with API-First approach. You can read more about API-first vs. code-first in the [Guide to API-first](https://www.postman.com/api-first/).
+
+Middleware
+----------
+
+FastAPI can be integrated by `middleware <https://fastapi.tiangolo.com/tutorial/middleware/>`__ to apply OpenAPI validation to your entire application.
+
+Add ``FastAPIOpenAPIMiddleware`` with OpenAPI object to your ``middleware`` list.
+
+.. code-block:: python
+  :emphasize-lines: 2,5
+
+    from fastapi import FastAPI
+    from openapi_core.contrib.fastapi.middlewares import FastAPIOpenAPIMiddleware
+
+    app = FastAPI()
+    app.add_middleware(FastAPIOpenAPIMiddleware, openapi=openapi)
+
+After that all your requests and responses will be validated.
+
+Also you have access to unmarshal result object with all unmarshalled request data through ``openapi`` scope of request object.
+
+.. code-block:: python
+
+    async def homepage(request):
+       # get parameters object with path, query, cookies and headers parameters
+       unmarshalled_params = request.scope["openapi"].parameters
+       # or specific location parameters
+       unmarshalled_path_params = request.scope["openapi"].parameters.path
+
+       # get body
+       unmarshalled_body = request.scope["openapi"].body
+
+       # get security data
+       unmarshalled_security = request.scope["openapi"].security
+
+Response validation
+^^^^^^^^^^^^^^^^^^^
+
+You can skip response validation process: by setting ``response_cls`` to ``None``
+
+.. code-block:: python
+  :emphasize-lines: 2
+
+    app = FastAPI()
+    app.add_middleware(FastAPIOpenAPIMiddleware, openapi=openapi, response_cls=None)
+
+Low level
+---------
+
+For low level integration see `Starlette <starlette.rst>`_ integration.

docs/integrations/index.rst

@@ -10,6 +10,7 @@ Openapi-core integrates with your popular libraries and frameworks. Each integra
     bottle
     django
     falcon
+    fastapi
     flask
     pyramid
     requests

openapi_core/contrib/fastapi/__init__.py

@@ -0,0 +1,9 @@
+from openapi_core.contrib.fastapi.middlewares import FastAPIOpenAPIMiddleware
+from openapi_core.contrib.fastapi.requests import FastAPIOpenAPIRequest
+from openapi_core.contrib.fastapi.responses import FastAPIOpenAPIResponse
+
+__all__ = [
+    "FastAPIOpenAPIMiddleware",
+    "FastAPIOpenAPIRequest",
+    "FastAPIOpenAPIResponse",
+]

openapi_core/contrib/fastapi/middlewares.py

@@ -0,0 +1,5 @@
+from openapi_core.contrib.starlette.middlewares import (
+    StarletteOpenAPIMiddleware as FastAPIOpenAPIMiddleware,
+)
+
+__all__ = ["FastAPIOpenAPIMiddleware"]

openapi_core/contrib/fastapi/requests.py

@@ -0,0 +1,10 @@
+from fastapi import Request
+
+from openapi_core.contrib.starlette.requests import (
+    StarletteOpenAPIRequest,
+)
+
+
+class FastAPIOpenAPIRequest(StarletteOpenAPIRequest):
+    def __init__(self, request: Request):
+        super().__init__(request)

openapi_core/contrib/fastapi/responses.py

@@ -0,0 +1,10 @@
+from fastapi import Response
+
+from openapi_core.contrib.starlette.responses import (
+    StarletteOpenAPIResponse,
+)
+
+
+class FastAPIOpenAPIResponse(StarletteOpenAPIResponse):
+    def __init__(self, response: Response, data: Optional[bytes] = None):
+        super().__init__(response, data=data)

poetry.lock

@@ -76,10 +76,12 @@ jsonschema-path = "^0.3.1"
 jsonschema = "^4.18.0"
 multidict = {version = "^6.0.4", optional = true}
 aioitertools = {version = "^0.11.0", optional = true}
+fastapi = {version = "^0.108.0", optional = true}
 
 [tool.poetry.extras]
 django = ["django"]
 falcon = ["falcon"]
+fastapi = ["fastapi"]
 flask = ["flask"]
 requests = ["requests"]
 aiohttp = ["aiohttp", "multidict"]
@@ -108,6 +110,7 @@ aiohttp = "^3.8.4"
 pytest-aiohttp = "^1.0.4"
 bump2version = "^1.0.1"
 pyflakes = "^3.1.0"
+fastapi = "^0.108.0"
 
 [tool.poetry.group.docs.dependencies]
 sphinx = ">=5.3,<8.0"

pyproject.toml

@@ -0,0 +1,9 @@
+from fastapi import FastAPI
+from fastapiproject.openapi import openapi
+from fastapiproject.routers import pets
+
+from openapi_core.contrib.fastapi.middlewares import FastAPIOpenAPIMiddleware
+
+app = FastAPI()
+app.add_middleware(FastAPIOpenAPIMiddleware, openapi=openapi)
+app.include_router(pets.router)

tests/integration/contrib/fastapi/data/v3.0/fastapiproject/__init__.py

@@ -0,0 +1,9 @@
+from pathlib import Path
+
+import yaml
+
+from openapi_core import OpenAPI
+
+openapi_spec_path = Path("tests/integration/data/v3.0/petstore.yaml")
+spec_dict = yaml.load(openapi_spec_path.read_text(), yaml.Loader)
+openapi = OpenAPI.from_dict(spec_dict)

tests/integration/contrib/fastapi/data/v3.0/fastapiproject/__main__.py

@@ -0,0 +1,105 @@
+from base64 import b64decode
+from typing import Annotated
+
+from fastapi import APIRouter
+from fastapi import Body
+from fastapi import Request
+from fastapi import Response
+from fastapi import status
+
+OPENID_LOGO = b64decode(
+    """
+R0lGODlhEAAQAMQAAO3t7eHh4srKyvz8/P5pDP9rENLS0v/28P/17tXV1dHEvPDw8M3Nzfn5+d3d
+3f5jA97Syvnv6MfLzcfHx/1mCPx4Kc/S1Pf189C+tP+xgv/k1N3OxfHy9NLV1/39/f///yH5BAAA
+AAAALAAAAAAQABAAAAVq4CeOZGme6KhlSDoexdO6H0IUR+otwUYRkMDCUwIYJhLFTyGZJACAwQcg
+EAQ4kVuEE2AIGAOPQQAQwXCfS8KQGAwMjIYIUSi03B7iJ+AcnmclHg4TAh0QDzIpCw4WGBUZeikD
+Fzk0lpcjIQA7
+"""
+)
+
+
+router = APIRouter(
+    prefix="/v1/pets",
+    tags=["pets"],
+    responses={404: {"description": "Not found"}},
+)
+
+
+@router.get("")
+async def list_pets(request: Request, response: Response):
+    assert request.scope["openapi"]
+    assert not request.scope["openapi"].errors
+    assert request.scope["openapi"].parameters.query == {
+        "page": 1,
+        "limit": 12,
+        "search": "",
+    }
+    data = [
+        {
+            "id": 12,
+            "name": "Cat",
+            "ears": {
+                "healthy": True,
+            },
+        },
+    ]
+    response.headers["X-Rate-Limit"] = "12"
+    return {"data": data}
+
+
+@router.post("")
+async def create_pet(request: Request):
+    assert request.scope["openapi"].parameters.cookie == {
+        "user": 1,
+    }
+    assert request.scope["openapi"].parameters.header == {
+        "api-key": "12345",
+    }
+    assert request.scope["openapi"].body.__class__.__name__ == "PetCreate"
+    assert request.scope["openapi"].body.name in ["Cat", "Bird"]
+    if request.scope["openapi"].body.name == "Cat":
+        assert request.scope["openapi"].body.ears.__class__.__name__ == "Ears"
+        assert request.scope["openapi"].body.ears.healthy is True
+    if request.scope["openapi"].body.name == "Bird":
+        assert (
+            request.scope["openapi"].body.wings.__class__.__name__ == "Wings"
+        )
+        assert request.scope["openapi"].body.wings.healthy is True
+
+    headers = {
+        "X-Rate-Limit": "12",
+    }
+    return Response(status_code=status.HTTP_201_CREATED, headers=headers)
+
+
+@router.get("/{petId}")
+async def detail_pet(request: Request, response: Response):
+    assert request.scope["openapi"]
+    assert not request.scope["openapi"].errors
+    assert request.scope["openapi"].parameters.path == {
+        "petId": 12,
+    }
+    data = {
+        "id": 12,
+        "name": "Cat",
+        "ears": {
+            "healthy": True,
+        },
+    }
+    response.headers["X-Rate-Limit"] = "12"
+    return {
+        "data": data,
+    }
+
+
+@router.get("/{petId}/photo")
+async def download_pet_photo():
+    return Response(content=OPENID_LOGO, media_type="image/gif")
+
+
+@router.post("/{petId}/photo")
+async def upload_pet_photo(
+    image: Annotated[bytes, Body(media_type="image/jpg")],
+):
+    assert image == OPENID_LOGO
+    return Response(status_code=status.HTTP_201_CREATED)