flight_summary.get_light and get_full Send Datetime Params in Wrong Format

[jayfiro]

flight_summary.get_light / get_full send datetime params in wrong format, API returns 400

Summary

FlightSummaryResource.get_light() and get_full() accept flight_datetime_from and flight_datetime_to as Python datetime objects, but serialize them with str(), which produces the format 2026-05-17 00:00:00+00:00 (space separator, with tz offset). The Flightradar24 API requires ISO 8601 in the format YYYY-MM-DDTHH:MM:SS (T separator, no offset), so every call with these parameters fails with a 400.

Environment

• fr24sdk version: 0.3.0 (latest as of report)
• Python: 3.10
• httpx: bundled with SDK

Minimal reproduction

from datetime import datetime, timezone
from fr24sdk.client import Client

with Client(api_token="<token>") as client:
    client.flight_summary.get_full(
        flights=["AA123"],
        flight_datetime_from=datetime(2026, 5, 17, tzinfo=timezone.utc),
        flight_datetime_to=datetime(2026, 5, 20, 23, 59, 59, tzinfo=timezone.utc),
    )

Actual outgoing request

GET https://fr24api.flightradar24.com/api/flight-summary/full
    ?flight_datetime_from=2026-05-17%2000%3A00%3A00%2B00%3A00
    &flight_datetime_to=2026-05-20%2023%3A59%3A59%2B00%3A00
    &flights=AA123

Actual response

fr24sdk.exceptions.BadRequestError: 400 Bad Request:
The 'flight_datetime_from' field must be a valid datetime in the format 'YYYY-MM-DDTHH:MM:SS'.,
The 'flight_datetime_to' field must be a valid datetime in the format 'YYYY-MM-DDTHH:MM:SS'.

Expected outgoing request

GET https://fr24api.flightradar24.com/api/flight-summary/full
    ?flight_datetime_from=2026-05-17T00%3A00%3A00
    &flight_datetime_to=2026-05-20T23%3A59%3A59
    &flights=AA123

The reproduction fails the same way when datetime objects are passed naive (no tzinfo) — str(datetime(2026, 5, 17)) produces '2026-05-17 00:00:00', which still uses a space rather than T.

Root cause

src/fr24sdk/resources/flight_summary.py, in _FlightSummaryParams._to_query_dict:

@model_serializer(mode="plain")
def _to_query_dict(self) -> dict[str, Any]:
    query: dict[str, Any] = {}
    for key, value in self.__dict__.items():
        if value is None:
            continue
        if isinstance(value, list):
            query[key] = ",".join(map(str, value))
        else:
            query[key] = str(value)   # ← bug: str(datetime) is not ISO 8601
    return query

str(datetime(...)) uses datetime.__str__, which is equivalent to isoformat(sep=' '). The API requires isoformat(sep='T') (and no timezone suffix).

Suggested fix

Special-case datetime (and date) in the serializer so they're formatted to the API's expected shape:

from datetime import date, datetime

@model_serializer(mode="plain")
def _to_query_dict(self) -> dict[str, Any]:
    query: dict[str, Any] = {}
    for key, value in self.__dict__.items():
        if value is None:
            continue
        if isinstance(value, list):
            query[key] = ",".join(map(str, value))
        elif isinstance(value, datetime):
            # API spec requires YYYY-MM-DDTHH:MM:SS with no timezone
            naive = value.astimezone(timezone.utc).replace(tzinfo=None) if value.tzinfo else value
            query[key] = naive.strftime("%Y-%m-%dT%H:%M:%S")
        elif isinstance(value, date):
            query[key] = value.isoformat()
        else:
            query[key] = str(value)
    return query

(If the API accepts/expects UTC offsets in the future, this can be adjusted, but the current docs and 400 message specify the un-offset format.)

Impact

• flight_summary.get_light(), get_full(), get_count(), and the deprecated count() are all affected.
• Any other resource whose _to_query_dict runs a datetime through str() is likely affected the same way. A grep for model_serializer + str(value) in src/fr24sdk/resources/ would surface any others.

Workaround we're using

Bypassing the typed resource and calling client.transport.request() directly with pre-formatted strings:

client.transport.request(
    "GET",
    "/api/flight-summary/full",
    params={
        "flights": flight_code,
        "flight_datetime_from": window_start.strftime("%Y-%m-%dT%H:%M:%S"),
        "flight_datetime_to": window_end.strftime("%Y-%m-%dT%H:%M:%S"),
    },
)

This works but gives up the typed parameter validation that's the main point of the SDK wrapper.