Replace FastAPI favicon with /favicon.ico (#85)

CHANGES.md

@@ -5,6 +5,8 @@
 
 - Fixed datatype of ctx.path (it was starlette.URL, now it is pydantic_core.Url).
 
+- Replaced FastAPI's favicon.ico with `/favicon.ico`.
+
 - Deprecate `dramatiq` submodule.
 
 

clean_python/fastapi/schema.py

@@ -3,14 +3,54 @@
 
 import yaml
 from fastapi import FastAPI
+from fastapi import Request
 from fastapi import Response
+from fastapi.openapi.docs import get_redoc_html
+from fastapi.openapi.docs import get_swagger_ui_html
+from fastapi.responses import HTMLResponse
+
+OPENAPI_URL = "/openapi.json"
+FAVICON_URL = "/favicon.ico"
 
 
 def add_cached_openapi_yaml(app: FastAPI) -> None:
-    @app.get("/openapi.yaml", include_in_schema=False)
+    @app.get(OPENAPI_URL.replace(".json", ".yaml"), include_in_schema=False)
     @lru_cache
     def openapi_yaml() -> Response:
         openapi_json = app.openapi()
         yaml_s = StringIO()
         yaml.dump(openapi_json, yaml_s)
         return Response(yaml_s.getvalue(), media_type="text/yaml")
+
+
+def get_openapi_url(request: Request) -> str:
+    root_path = request.scope.get("root_path", "").rstrip("/")
+    return root_path + OPENAPI_URL
+
+
+def add_swagger_ui(app: FastAPI, title: str, client_id: str | None) -> None:
+    # Code below is copied from fastapi.applications to modify the favicon
+    @app.get("/docs", include_in_schema=False)
+    async def swagger_ui_html(request: Request) -> HTMLResponse:
+        return get_swagger_ui_html(
+            openapi_url=get_openapi_url(request),
+            title=f"{title} - Swagger UI",
+            swagger_favicon_url=FAVICON_URL,
+            init_oauth={
+                "clientId": client_id,
+                "usePkceWithAuthorizationCodeGrant": True,
+            }
+            if client_id
+            else None,
+        )
+
+
+def add_redoc(app: FastAPI, title: str) -> None:
+    # Code below is copied from fastapi.applications to modify the favicon
+    @app.get("/redoc", include_in_schema=False)
+    async def redoc_html(request: Request) -> HTMLResponse:
+        return get_redoc_html(
+            openapi_url=get_openapi_url(request),
+            title=f"{title} - ReDoc",
+            redoc_favicon_url=FAVICON_URL,
+        )

clean_python/fastapi/service.py

@@ -35,26 +35,15 @@
 from .resource import clean_resources
 from .resource import Resource
 from .schema import add_cached_openapi_yaml
+from .schema import add_redoc
+from .schema import add_swagger_ui
 from .security import AuthSettings
 from .security import OAuth2Schema
 from .security import set_auth_scheme
 
 __all__ = ["Service"]
 
 
-def get_swagger_ui_init_oauth(
-    auth: AuthSettings | None = None,
-) -> dict[str, Any] | None:
-    return (
-        None
-        if auth is None or not auth.oauth2.login_enabled()
-        else {
-            "clientId": auth.oauth2.client_id,
-            "usePkceWithAuthorizationCodeGrant": True,
-        }
-    )
-
-
 AnyHttpUrlTA = TypeAdapter(AnyHttpUrl)
 
 
@@ -118,6 +107,7 @@ def _create_root_app(
                 for x in self.versions
             ],
             root_path_in_servers=False,
+            openapi_url=None,  # disables redoc and docs as well
         )
         if access_logger_gateway is not None:
             app.middleware("http")(
@@ -127,16 +117,26 @@ def _create_root_app(
         return app
 
     def _create_versioned_app(
-        self, version: APIVersion, auth_scheme: OAuth2Schema | None, **fastapi_kwargs
+        self,
+        version: APIVersion,
+        auth_scheme: OAuth2Schema | None,
+        title: str,
+        description: str,
+        dependencies: list[Depends],
+        client_id: str | None,
     ) -> FastAPI:
         resources = [x for x in self.resources if x.version == version]
         app = FastAPI(
+            title=title,
+            description=description,
+            dependencies=dependencies,
             version=version.prefix,
             tags=sorted(
                 [x.get_openapi_tag().model_dump() for x in resources],
                 key=lambda x: x["name"],
             ),
-            **fastapi_kwargs,
+            redoc_url=None,  # added manually later in add_redoc
+            docs_url=None,  # added manually later in add_swagger_ui
         )
         for resource in resources:
             app.include_router(
@@ -156,6 +156,8 @@ def _create_versioned_app(
         app.add_exception_handler(PermissionDenied, permission_denied_handler)
         app.add_exception_handler(Unauthorized, unauthorized_handler)
         add_cached_openapi_yaml(app)
+        add_swagger_ui(app, title=title, client_id=client_id)
+        add_redoc(app, title=title)
         return app
 
     def create_app(
@@ -177,14 +179,18 @@ def create_app(
             on_shutdown=on_shutdown,
             access_logger_gateway=access_logger_gateway,
         )
-        fastapi_kwargs = {
-            "title": title,
-            "description": description,
-            "dependencies": [Depends(set_request_context)],
-            "swagger_ui_init_oauth": get_swagger_ui_init_oauth(auth),
-        }
+        dependencies = [Depends(set_request_context)]
         versioned_apps = {
-            v: self._create_versioned_app(v, auth_scheme=auth_scheme, **fastapi_kwargs)
+            v: self._create_versioned_app(
+                v,
+                auth_scheme=auth_scheme,
+                title=title,
+                description=description,
+                dependencies=dependencies,
+                client_id=auth.oauth2.client_id
+                if auth and auth.oauth2.login_enabled()
+                else None,
+            )
             for v in self.versions
         }
         for v, versioned_app in versioned_apps.items():

tests/fastapi/test_service_schema.py

@@ -1,3 +1,4 @@
+from html.parser import HTMLParser
 from http import HTTPStatus
 
 import pytest
@@ -150,3 +151,26 @@ def test_schema_yaml(client: TestClient, expected_schema: Json):
     actual = yaml.safe_load(response.content.decode("utf-8"))
 
     assert actual == expected_schema
+
+
+@pytest.mark.parametrize("path", ["/v1/docs", "/v1/redoc"])
+def test_favicon(client: TestClient, path: str):
+    response = client.get(path)
+    assert response.status_code == HTTPStatus.OK
+
+    # parse favicon from html
+    found = set()
+
+    class FaviconParser(HTMLParser):
+        def handle_starttag(self, tag, attrs):
+            if tag == "link":
+                attr_dict = dict(attrs)
+                if (
+                    attr_dict.get("rel") in {"icon", "shortcut icon"}
+                    and "href" in attr_dict
+                ):
+                    found.add(attr_dict["href"])
+
+    FaviconParser().feed(response.text)
+
+    assert found == {"/favicon.ico"}