munch-ease-backend/api/openapi.py

from __future__ import annotations

from typing import Any

from fastapi import FastAPI


def extend_with_problem_and_cookie_auth(app: FastAPI) -> None:
    """Augment FastAPI's OpenAPI spec with RFC7807 responses and cookie auth.

    This mutates the app's OpenAPI generation in-place while delegating to the
    original generator for the base schema.
    """
    original_openapi = app.openapi

    def custom_openapi() -> dict[str, Any]:
        spec = original_openapi()
        components = spec.setdefault("components", {})
        responses = components.setdefault("responses", {})
        security_schemes = components.setdefault("securitySchemes", {})

        # Standard ProblemDetails responses
        responses.setdefault(
            "Problem400",
            {
                "description": "Bad Request",
                "content": {
                    "application/problem+json": {},
                    "application/json": {"schema": {"$ref": "#/components/schemas/ProblemDetails"}},
                },
            },
        )
        responses.setdefault(
            "Problem404",
            {
                "description": "Not Found",
                "content": {
                    "application/problem+json": {},
                    "application/json": {"schema": {"$ref": "#/components/schemas/ProblemDetails"}},
                },
            },
        )
        responses.setdefault(
            "Problem422",
            {
                "description": "Validation Error",
                "content": {
                    "application/problem+json": {"schema": {"$ref": "#/components/schemas/ProblemDetails"}},
                    "application/json": {"schema": {"$ref": "#/components/schemas/ProblemDetails"}},
                },
            },
        )

        # Cookie-based auth for documentation (does not enforce at runtime)
        security_schemes.setdefault(
            "cookieAuth",
            {
                "type": "apiKey",
                "in": "cookie",
                "name": "user_id",
                "description": "Authentication via user_id cookie (session-style).",
            },
        )

        # Normalize v1 responses and mark cookie security for known endpoints
        paths = spec.get("paths", {})
        protected_ops: set[str] = {
            "parseRecipe",
            "createRecipe",
            "deleteRecipe",
            "markMealConsumed",
            "deleteMeal",
            "purchaseIngredients",
            "getMyShoppingList",
            "syncMyShoppingList",
            "requestMeal",
            "unrequestMeal",
            "refresh",
        }
        for path, ops in paths.items():
            if not isinstance(path, str) or not path.startswith("/api/v1/"):
                continue
            if not isinstance(ops, dict):
                continue
            for _method, op in ops.items():
                if not isinstance(op, dict):
                    continue
                resp = op.get("responses")
                if not isinstance(resp, dict):
                    continue
                if "400" in resp:
                    resp["400"] = {"$ref": "#/components/responses/Problem400"}
                if "404" in resp:
                    resp["404"] = {"$ref": "#/components/responses/Problem404"}
                if "422" not in resp:
                    resp["422"] = {"$ref": "#/components/responses/Problem422"}

                op_id = op.get("operationId")
                if isinstance(op_id, str) and op_id in protected_ops:
                    security = op.setdefault("security", [])
                    if not any(isinstance(s, dict) and "cookieAuth" in s for s in security):
                        security.append({"cookieAuth": []})

        # Keep endpoint-specific schemas driven by route declarations only (no forced overrides)

        return spec

    # Rebind app.openapi to our generator (FastAPI supports this pattern). Mypy needs a narrow ignore here.
    app.openapi = custom_openapi  # type: ignore[method-assign]