✨ Add docs/tests extending OpenAPI (#126)

docs/src/extending_openapi/tutorial001.py

@@ -0,0 +1,28 @@
+from fastapi import FastAPI
+from fastapi.openapi.utils import get_openapi
+
+app = FastAPI()
+
+
+@app.get("/items/")
+async def read_items():
+    return [{"name": "Foo"}]
+
+
+def custom_openapi():
+    if app.openapi_schema:
+        return app.openapi_schema
+    openapi_schema = get_openapi(
+        title="Custom title",
+        version="2.5.0",
+        description="This is a very custom OpenAPI schema",
+        routes=app.routes,
+    )
+    openapi_schema["info"]["x-logo"] = {
+        "url": "https://fastapi.tiangolo.com/img/logo-margin/logo-teal.png"
+    }
+    app.openapi_schema = openapi_schema
+    return app.openapi_schema
+
+
+app.openapi = custom_openapi