Robyn¶

hare.contrib.frameworks.robyn connects hare to a Robyn application. Install it with the robyn extra (Robyn 0.88, pydantic).

from pydantic import BaseModel, ConfigDict

from hare.contrib.frameworks import PageSchema
from hare.contrib.frameworks.robyn import HareRobyn
from hare.contrib.request_query import Page

HARE_CONFIG = {
    "connections": {"default": "postgresql://library:secret@localhost:5432/library"},
    "apps": {"library": {"models": ["library.models"], "default_connection": "default"}},
}

app = HareRobyn(__file__, hare_config=HARE_CONFIG, atomic_requests=True)


class BookSchema(BaseModel):
    model_config = ConfigDict(from_attributes=True)

    id: int
    title: str


@app.get("/books", response_model=PageSchema[BookSchema])
async def list_books(books: BookQuery) -> Page[Book]:
    return await books.page()

`HareRobyn`¶

class HareRobyn(Robyn):
    def __init__(
        self,
        file_object: str,
        *,
        hare_config: Mapping[str, Any] | HareConfig | str,
        atomic_requests: bool | Sequence[str] = False,
        openapi: OpenAPI | None = None,
        health_routes: HealthRoutes | None = None,
        **kwargs: Any,
    ) -> None: ...

HareRobyn is a Robyn application; hare_config is what Hare.init(config=...) takes, file_object and kwargs what Robyn() takes.

The HareContext. The models are bound when the application is created; the context opens when a worker process starts — before the application's own startup_handler — and closes when it stops, after its own shutdown_handler. The context is the global fallback, so every request sees it. On shutdown Hare.close_connections() also waits for the background observers still running.
Request queries are checked at startup. RequestQuery.check_declarations() runs once the models are set up: a wrong request query stops the process from starting.
Request queries for handlers and their parameters in the OpenAPI schema — see below.
Responses validated with the route's response_model — see below.
ORM errors as HTTP answers (HareExceptionHandlers):

Error	Answer
`InvalidRequestQuery`	`422 Unprocessable Content` as Robyn answers an invalid pydantic body itself: `{"error": "Validation Error", "detail": [{"type", "loc": ["query", name], "msg", "input"}]}`; an error of the whole query (a model validator's) has `"loc": ["query"]` and the query's parameters as `input`
`DoesNotExist`	`404 Not Found`, `{"detail": "Not Found"}`
`IntegrityError` (unique, foreign key, protected relation)	`409 Conflict`, `{"detail": "Conflict"}` — without the database's message, which names tables and constraints
`TransactionRetryError` (a serialization failure or deadlock — the request may be sent again)	`409 Conflict`, `{"detail": "Conflict"}`
`ValidationError` (a value a field refuses: out of its range, too long, a null byte PostgreSQL refuses)	`422 Unprocessable Content`, the field's message in `detail`
`RequestQueryForbidden` (a parameter asks for what the request may not see: deleted rows without `may_see_deleted()`)	`403 Forbidden`, the reason in `detail`
`ApiGetterError` (a value of another service a request query's `Meta.api_getter` requires couldn't be loaded)	`502 Bad Gateway`, without the error's message, which names the service and the values asked

Any other error is left to Robyn (500). Robyn keeps one exception handler per application and hands it to each route when the route is declared: an application answering errors itself sets its handler with exception() before declaring routes and calls HareExceptionHandlers.get_response(error) first in it. - A request's own state. Each request starts with an empty count of RepeatedQueryDetector (a before_request hook). Only its own writes send its reads to the connection written through (reading your own writes) — not the writes of the requests its task served before or of the application's startup. - A transaction per request with atomic_requests — see below.

A router of the application is a HareSubRouter — a SubRouter whose routes get the same, and its transactions once the application includes it:

from hare.contrib.frameworks.robyn import HareSubRouter

chapters = HareSubRouter(prefix="/chapters")


@chapters.get("/:pk", response_model=ChapterSchema)
async def get_chapter(chapter: ChapterQuery) -> Chapter:
    return await chapter.get()


app.include_router(chapters)

Request queries for handlers¶

A handler's parameter annotated with a request query class (books: BookQuery) gets the query built from the request: its query string — a repeated name for each value of a list, ?status__in=draft&status__in=published — and its path parameters, for the parameters marked InPath() (pk: Annotated[KeyColumns[int, int], InPath()] with /chapters/:pk). Robyn itself would read a pydantic model from the request's body. The query gets the request (query.request) and the request's whole address for a page's next and previous. A value the query refuses is answered with 422.

The OpenAPI schema (HareOpenAPI, the application's by default) lists each parameter of the query — a query parameter, a path parameter for one marked InPath() — with its type, limits, enum and description.

Responses¶

A route's response — a row, a list, a page — is validated with its response_model from its attributes and answered as JSON with the route's status_code (200 by default); Robyn itself only validates a returned dict. A returned Response is sent as it is. The schemas of a row, a list and a page — see Web frameworks.

A transaction per request: `atomic_requests`¶

HareRobyn(..., atomic_requests=True) runs each handler in a transaction, committed before Robyn sends the response; a handler marked RequestTransaction.skip runs without it, and so does a const route:

from hare.contrib.frameworks import RequestTransaction


@app.post("/imports")
@RequestTransaction.skip
async def import_books(request: Request) -> None: ...

When the transaction commits or rolls back — see Web frameworks.

A tenant per request¶

Robyn runs a request's before_request hooks apart from its handler: a scope a synchronous hook sets with Tenancy.set() reaches the handler, one an async hook sets doesn't. HareRobyn starts every request with no tenant scope and no query tags — before the application's own hooks — so a request without a tenant never reads the previous request's rows:

@app.before_request()
def set_tenant(request: Request) -> Request:
    company = request.headers.get("x-company")
    if company:
        Tenancy.set(int(company))
    return request

A request the hook gives no tenant queries a tenant-scoped model with no scope and gets QueryError. A handler may also open the scope itself — with Tenancy.scope(company_id): ....

Health routes: `health_routes`¶

from hare.contrib.frameworks.health_routes import HealthRoutes
from hare.health import HealthCheck

app = HareRobyn(__file__, hare_config=HARE_CONFIG, health_routes=HealthRoutes(HealthCheck()))

The readiness and liveness routes it adds — see Web frameworks.

Tests¶

Robyn's TestClient runs the application in an event loop of its own — with hare's pytest plugin take hare_app_transactional_db: the application takes the test's context, its writes commit, and every table is emptied when the test ends — see Application tests. It needs a server database or a SQLite file.