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Application State

Application state is data shared across all requests and handlers. Attach any Python object to the server with app_data(), then read it from any handler via request.app_data.

Setting app data​

from oxapy import Oxapy, Router, get


class AppState:
    def __init__(self):
        self.counter = 0
        self.db_pool = None  # e.g. a database connection pool


@get("/count")
def count(request):
    state = request.app_data
    state.counter += 1
    return {"count": state.counter}


def main():
    (
        Oxapy(("127.0.0.1", 5555))
        .app_data(AppState())
        .attach(Router().route(count))
        .run()
    )


if __name__ == "__main__":
    main()

Every request to /count increments the same counter:

curl http://127.0.0.1:5555/count   # {"count": 1}
curl http://127.0.0.1:5555/count   # {"count": 2}

What to store​

app_data accepts any Python object, which makes it the natural home for:

  • Database connection pools and ORM sessions
  • Caches and in-memory stores
  • Configuration objects
  • Shared services (mailers, queues, external API clients)
class AppState:
    def __init__(self):
        self.counter = 0
        self.db_pool = create_database_pool()

Notes​

  • If no app_data was set, request.app_data returns None.
  • State lives in the server process. With multiple worker processes each worker has its own copy; use a shared store (database, Redis) for data that must be visible across workers.

Next steps​