Refactor radar system

python_app/models/json_fields.py

@@ -0,0 +1,62 @@
+"""Shared strict scalar and object readers for configuration codecs."""
+
+from __future__ import annotations
+
+import math
+from typing import Any
+
+
+def json_object(value: Any, context: str) -> dict[str, Any]:
+    """Read an object; a missing or null section keeps its defaults."""
+    if value is None:
+        return {}
+    if not isinstance(value, dict):
+        raise ValueError(f"{context} must be a JSON object")
+    return value
+
+
+def _value(payload: dict[str, Any], key: str, default: Any) -> Any:
+    value = payload.get(key, default)
+    return default if value is None else value
+
+
+def read_int(payload: dict[str, Any], key: str, default: int) -> int:
+    """Read a JSON integer without truncation or boolean coercion."""
+    value = _value(payload, key, default)
+    if isinstance(value, bool) or not isinstance(value, int):
+        raise ValueError(f"{key} must be a JSON integer")
+    return value
+
+
+def read_str(payload: dict[str, Any], key: str, default: str) -> str:
+    """Read a JSON string without converting other scalar types."""
+    value = _value(payload, key, default)
+    if not isinstance(value, str):
+        raise ValueError(f"{key} must be a JSON string")
+    return value
+
+
+def read_bool(payload: dict[str, Any], key: str, default: bool) -> bool:
+    """Read a JSON boolean."""
+    value = _value(payload, key, default)
+    if not isinstance(value, bool):
+        raise ValueError(f"{key} must be a JSON boolean")
+    return value
+
+
+def read_float(payload: dict[str, Any], key: str, default: float) -> float:
+    """Read a finite JSON number, including overflow-safe integer conversion."""
+    return finite_number(_value(payload, key, default), key)
+
+
+def finite_number(value: Any, context: str) -> float:
+    """Validate a number without accepting booleans, strings or nonfinite values."""
+    if isinstance(value, bool) or not isinstance(value, (int, float)):
+        raise ValueError(f"{context} must be a JSON number")
+    try:
+        result = float(value)
+    except OverflowError as exc:
+        raise ValueError(f"{context} must be a finite number") from exc
+    if not math.isfinite(result):
+        raise ValueError(f"{context} must be a finite number")
+    return result