Baseline API

In one sentence

The baseline endpoints are the production-shaped service that the anti-patterns are injected into. Nothing here is slow; use them to set the scene.

The baseline lives in app/routers/orders.py, mounted at /orders. Each handler gets a session from the lifespan-scoped sessionmaker through Depends(get_session), which is the correct AP2 pattern.

Endpoints

Method	Path	Purpose	Status
POST	/orders	Create an order and its items	201
GET	/orders	List recent orders, newest first	200
GET	/orders/{order_id}	Order detail with items	200, or 404

GET /orders takes limit (default 50). It orders by created_at descending.

GET /orders/{order_id} uses selectinload(Order.items), so the items come from one extra query, not one per order. This is the "good" loading strategy from AP3.

Try it

Run these after setup, from any terminal:

curl "localhost:8000/orders?limit=3"

Fetch the newest order's ID and its detail:

ORDER=$(curl -s "localhost:8000/orders?limit=1" | python3 -c "import sys,json;print(json.load(sys.stdin)[0]['id'])")
curl localhost:8000/orders/$ORDER

Create an order for an existing customer:

CUSTOMER=$(curl -s "localhost:8000/orders?limit=1" | python3 -c "import sys,json;print(json.load(sys.stdin)[0]['customer_id'])")
curl -X POST localhost:8000/orders -H 'content-type: application/json' \
  -d "{\"customer_id\":\"$CUSTOMER\",\"items\":[{\"sku\":\"SKU-0001AB\",\"quantity\":2,\"unit_price\":9.5}]}"

SKU format

The AP4 transforms validate SKUs against ^SKU-\d{4}[A-Za-z]{2}$, for example SKU-0001AB. The baseline POST endpoint does not enforce it.

Response shapes

These come from app/schemas.py. Values are placeholders.

GET /orders returns a list of OrderRead:

[
  {
    "id": "<uuid>",
    "customer_id": "<uuid>",
    "status": "pending",
    "created_at": "<ISO-8601 datetime>"
  }
]

GET /orders/{id} and POST /orders return OrderDetailRead, which adds items:

{
  "id": "<uuid>",
  "customer_id": "<uuid>",
  "status": "pending",
  "created_at": "<ISO-8601 datetime>",
  "items": [
    { "id": "<uuid>", "sku": "SKU-0001AB", "quantity": 2, "unit_price": 9.5 }
  ]
}

A missing order returns 404 with {"detail": "Order not found"}.

Related

• Architecture: where these handlers sit in the app
• AP3 — Lazy loading: why the detail endpoint uses selectinload
• Endpoints reference: every endpoint, including the demos