67 lines
2.9 KiB
Python
67 lines
2.9 KiB
Python
"""Read-only chronological SCADA paging shared by REST and replay processing."""
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from __future__ import annotations
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import base64
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import hashlib
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import json
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import math
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from datetime import datetime
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from app.domain.schemas.scada import ScadaRawPage, ScadaRawReading
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from app.infra.db.timescaledb.repositories.scada import ScadaRepository
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def validate_window(start: datetime, end: datetime) -> None:
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if start.tzinfo is None or end.tzinfo is None or start >= end:
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raise ValueError("需要带时区、结束晚于开始的 SCADA 时间区间")
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def raw_reading(row: dict) -> ScadaRawReading:
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value = row["monitored_value"]
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invalid = value is not None and not math.isfinite(float(value))
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return ScadaRawReading(
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time=row["time"], device_id=row["device_id"],
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monitored_value=None if invalid else value,
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quality="invalid" if invalid else "missing" if value is None else "unvalidated",
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)
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async def read_raw_page(
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conn, *, project_id: str, device_ids: list[str], start: datetime,
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end: datetime, limit: int = 500, cursor: str | None = None,
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through: datetime | None = None,
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) -> ScadaRawPage:
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validate_window(start, end)
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ids = sorted(set(device_ids))
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if not ids or len(ids) > 500 or not 1 <= limit <= 500:
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raise ValueError("请选择 1 至 500 个设备，每页最多 500 条")
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cap = min(through or end, end)
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if cap.tzinfo is None or cap < start:
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raise ValueError("模拟时间不在可读取区间内")
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signature = hashlib.sha256(json.dumps(
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[project_id, ids, start.isoformat(), end.isoformat()], separators=(",", ":")
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).encode()).hexdigest()
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after = None
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if cursor:
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try:
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data = json.loads(base64.urlsafe_b64decode(cursor.encode()))
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frozen = datetime.fromisoformat(data["through"])
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last = datetime.fromisoformat(data["time"])
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if (data["query"] != signature or frozen.tzinfo is None or last.tzinfo is None
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or frozen > cap or not start <= last <= frozen or data["device"] not in ids):
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raise ValueError()
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cap, after = frozen, (last, data["device"])
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except (ValueError, KeyError, TypeError, UnicodeError) as exc:
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raise ValueError("SCADA 分页游标无效或查询范围已改变") from exc
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rows = await ScadaRepository.get_raw_page(conn, ids, start, end, cap, limit + 1, after)
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selected = rows[:limit]
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next_cursor = None
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if len(rows) > limit:
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last = selected[-1]
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next_cursor = base64.urlsafe_b64encode(json.dumps({
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"query": signature, "through": cap.isoformat(),
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"time": last["time"].isoformat(), "device": last["device_id"],
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}, separators=(",", ":")).encode()).decode()
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return ScadaRawPage(items=[raw_reading(row) for row in selected],
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next_cursor=next_cursor, scanned_through=cap)
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