fix

http-api/app/middlewares/tenant_middelware.py

@@ -0,0 +1,123 @@
+from http import HTTPStatus
+
+from auth import AuthFlowType
+from aws_lambda_powertools.event_handler.api_gateway import (
+    APIGatewayHttpResolver,
+    Response,
+)
+from aws_lambda_powertools.event_handler.exceptions import (
+    BadRequestError,
+    NotFoundError,
+    ServiceError,
+)
+from aws_lambda_powertools.event_handler.middlewares import (
+    BaseMiddlewareHandler,
+    NextMiddleware,
+)
+from layercake.dynamodb import ComposeKey, DynamoDBCollection, KeyPair
+from pydantic import UUID4, BaseModel
+
+from .authentication_middleware import User
+
+class Tenant(BaseModel):
+    id: UUID4 | str
+    name: str
+
+
+class TenantMiddleware(BaseMiddlewareHandler):
+    """Middleware that associates a Tenant instance with the request context based on the authentication flow.
+
+    For API authentication (`AuthFlowType.API_AUTH`), it assigns tenant information directly from the authorizer context.
+    For user authentication (`AuthFlowType.USER_AUTH`), it gets the Tenant ID from the specified request header.
+
+    Parameters
+    ----------
+    collect : DynamoDBCollection
+        The DynamoDB collection used to validate user access and retrieve tenant information.
+    header : str, optional
+        The request header name containing the tenant ID. Defaults to `'X-Tenant'`.
+    """
+
+    def __init__(
+        self,
+        collect: DynamoDBCollection,
+        /,
+        header: str = 'X-Tenant',
+    ) -> None:
+        self.collect = collect
+        self.header = header
+
+    def handler(
+        self,
+        app: APIGatewayHttpResolver,
+        next_middleware: NextMiddleware,
+    ) -> Response:
+        context = app.current_event.request_context.authorizer.get_lambda
+        auth_flow_type = context.get('auth_flow_type')
+
+        if auth_flow_type == AuthFlowType.API_AUTH:
+            app.append_context(tenant=Tenant(**context['tenant']))
+
+        if auth_flow_type == AuthFlowType.USER_AUTH:
+            app.append_context(
+                tenant=_tenant(
+                    app.current_event.headers.get(self.header),
+                    app.context.get('user'),  # type: ignore
+                    collect=self.collect,
+                )
+            )
+
+        return next_middleware(app)
+
+
+class ForbiddenError(ServiceError):
+    def __init__(self, *args, **kwargs):
+        super().__init__(HTTPStatus.FORBIDDEN, 'Deny')
+
+
+def _tenant(
+    tenant_id: str | None,
+    user: User,
+    /,
+    collect: DynamoDBCollection,
+) -> Tenant:
+    """Get a Tenant instance based on the provided tenant_id and user's access permissions.
+
+    Parameters
+    ----------
+    tenant_id : str | None
+        The identifier of the tenant. Must not be None or empty.
+    user : User
+        The user attempting to access the tenant.
+    collect : DynamoDBCollection
+        The DynamoDB collection used to retrieve tenant information.
+
+    Returns
+    -------
+    Tenant
+        The Tenant instance corresponding to the provided tenant_id.
+
+    Raises
+    ------
+    BadRequestError
+        If tenant_id is not provided.
+    ForbiddenError
+        If the user lacks the necessary ACL permissions for the specified tenant_id.
+    NotFoundError
+        If tenant not found.
+    """
+    if not tenant_id:
+        raise BadRequestError('Missing tenant')
+
+    # Ensure user has ACL
+    collect.get_item(
+        KeyPair(user.id, ComposeKey(tenant_id, prefix='acls')),
+        exception_cls=ForbiddenError,
+    )
+
+    # For root tenant, provide the default Tenant
+    if tenant_id == '*':
+        return Tenant(id=tenant_id, name='default')
+
+    obj = collect.get_item(KeyPair(tenant_id, '0'), exception_cls=NotFoundError)
+    return Tenant.parse_obj(obj)