src/arnhem/arnhem.py
"""Asynchronous Python client providing Open Data information of Arnhem."""
from __future__ import annotations
import asyncio
import socket
from dataclasses import dataclass
from importlib import metadata
from typing import Any, Self, cast
from aiohttp import ClientError, ClientSession
from aiohttp.hdrs import METH_GET
from yarl import URL
from .exceptions import (
ODPArnhemConnectionError,
ODPArnhemError,
ODPArnhemNoResultsError,
)
from .models import ParkingSpot
@dataclass
class ODPArnhem:
"""Main class for handling data fetchting from Open Data Platform of Arnhem."""
request_timeout: float = 10.0
session: ClientSession | None = None
_close_session: bool = False
async def _request(
self,
uri: str,
*,
method: str = METH_GET,
params: dict[str, Any] | None = None,
) -> Any:
"""Handle a request to the Open Data Platform API of Arnhem.
Args:
----
uri: Request URI, without '/', for example, 'status'
method: HTTP method to use, for example, 'GET'
params: Extra options to improve or limit the response.
Returns:
-------
A Python dictionary with the response from
the Open Data Platform API of Arnhem.
Raises:
------
ODPArnhemConnectionError: An error occurred while
communicating with the Open Data Platform API of Arnhem.
ODPArnhemError: Received an unexpected response from
the Open Data Platform API of Arnhem.
"""
version = metadata.version(__package__)
url = URL.build(
scheme="https",
host="geo.arnhem.nl",
path="/arcgis/rest/services/",
).join(
URL(uri),
)
headers = {
"Accept": "application/json",
"User-Agent": f"PythonODPArnhem/{version}",
}
if self.session is None:
self.session = ClientSession()
self._close_session = True
try:
async with asyncio.timeout(self.request_timeout):
response = await self.session.request(
method,
url,
params=params,
headers=headers,
ssl=True,
)
response.raise_for_status()
except TimeoutError as exception:
msg = "Timeout occurred while connecting to the Open Data Platform API."
raise ODPArnhemConnectionError(msg) from exception
except (ClientError, socket.gaierror) as exception:
msg = "Error occurred while communicating with the Open Data Platform API."
raise ODPArnhemConnectionError(msg) from exception
content_type = response.headers.get("Content-Type", "")
if "application/json" not in content_type:
text = await response.text()
msg = "Unexpected content type response from the Open Data Platform API."
raise ODPArnhemError(msg, {"Content-Type": content_type, "response": text})
return cast(dict[str, Any], await response.json())
async def locations(
self,
limit: int = 10,
set_filter: str = "1=1",
) -> list[ParkingSpot]:
"""Get all the parking locations.
Args:
----
limit: The number of results to return.
filter: A filter to apply to the results.
Returns:
-------
A list of ParkingSpot objects.
"""
msg: str = "No results found, check your filter."
locations = await self._request(
"OpenData/Parkeervakken/MapServer/0/query",
params={
"where": set_filter,
"outFields": "*",
"outSR": "4326",
"f": "json",
"resultRecordCount": limit,
},
)
try:
results: list[ParkingSpot] = [
ParkingSpot.from_json(item) for item in locations["features"]
]
except KeyError as exception:
# when wrong filter is given
raise ODPArnhemNoResultsError(msg) from exception
# when filter is incorrect/empty
if locations["features"] == []:
raise ODPArnhemNoResultsError(msg)
return results
async def close(self) -> None:
"""Close open client session."""
if self.session and self._close_session:
await self.session.close()
async def __aenter__(self) -> Self:
"""Async enter.
Returns
-------
The Open Data Platform Arnhem object.
"""
return self
async def __aexit__(self, *_exc_info: object) -> None:
"""Async exit.
Args:
----
_exc_info: Exec type.
"""
await self.close()