alti3 Custom Types
Execution Workflow
- Define the domain type and its canonical wire representation.
- Register type decoders/encoders at the appropriate layer.
- Ensure OpenAPI schema generation remains accurate for custom values.
- Add round-trip tests for decode, business usage, and encode output.
Implementation Rules
- Keep serialization behavior stable and backward compatible.
- Fail fast with actionable error messages on invalid input.
- Avoid ambiguous representations that vary by locale/timezone.
- Keep custom type support centralized to prevent drift.
Example Pattern
from datetime import datetime
from litestar import Litestar, get
def parse_timestamp(value: str) -> datetime:
return datetime.fromisoformat(value)
@get("/echo-ts/{value:str}")
async def echo_timestamp(value: datetime) -> dict[str, str]:
return {"value": value.isoformat()}
app = Litestar(route_handlers=[echo_timestamp], type_decoders=[(datetime, parse_timestamp)])
Validation Checklist
- Confirm valid payloads decode to the intended Python types.
- Confirm invalid payloads return deterministic client errors.
- Confirm encoded responses and generated schemas match actual runtime behavior.
Cross-Skill Handoffs
- Use
litestar-openapiif schema customization is substantial. - Use
litestar-requestsandlitestar-responseswhen custom types appear at API boundaries.