[FEATURE] Pydantic backend to Data Validation

pyproject.toml

@@ -21,6 +21,7 @@ requires-python = ">=3.7"
 dependencies = [
     "numpy",        # for vector math
     "jsonschema",   # for spec validation
+    "pydantic>=2.5",
 ]
     [project.urls]
     repository = "https://github.com/sigmf/sigmf-python"

sigmf/component/__init__.py

@@ -0,0 +1,6 @@
+# Copyright: Multiple Authors
+#
+# This file is part of sigmf-python. https://github.com/sigmf/sigmf-python
+#
+# SPDX-License-Identifier: LGPL-3.0-or-later
+"""Contains pydantic.BaseModel components for defining the SigMF schema."""

sigmf/component/extensions/__init__.py

@@ -0,0 +1,6 @@
+# Copyright: Multiple Authors
+#
+# This file is part of sigmf-python. https://github.com/sigmf/sigmf-python
+#
+# SPDX-License-Identifier: LGPL-3.0-or-later
+"""Contains core:extensions pydantic.BaseModel components for defining the SigMF schema."""

sigmf/component/extensions/core.py

@@ -0,0 +1,24 @@
+# Copyright: Multiple Authors
+#
+# This file is part of sigmf-python. https://github.com/sigmf/sigmf-python
+#
+# SPDX-License-Identifier: LGPL-3.0-or-later
+"""Core:extension definition for SigMFGlobal in Pydantic."""
+
+from pydantic import BaseModel, ConfigDict, Field
+
+from sigmf.component.pydantic_types import VERSION_STR
+
+
+class SigMFCoreExtension(BaseModel):
+    """core:extensions to a Global Object."""
+
+    model_config = ConfigDict(extra="forbid")
+
+    name: str = Field(..., description="The name of the SigMF extension namespace.", frozen=True)
+    version: VERSION_STR = Field(
+        ..., description="The version of the extension namespace specification used.", examples=["1.0.0"], frozen=True
+    )
+    optional: bool = Field(
+        ..., description="If this field is `true`, the extension is REQUIRED to parse this Recording.", frozen=True
+    )

sigmf/component/geo_json.py

@@ -0,0 +1,66 @@
+# Copyright: Multiple Authors
+#
+# This file is part of sigmf-python. https://github.com/sigmf/sigmf-python
+#
+# SPDX-License-Identifier: LGPL-3.0-or-later
+"""GEOJson Definitions in Pydantic."""
+
+from typing import List, Optional, Dict, Any
+from typing_extensions import Literal
+from pydantic import (
+    BaseModel,
+    Field,
+    AliasPath,
+    AliasChoices,
+    model_serializer,
+    model_validator,
+)
+
+
+class WGS84Coordinate(BaseModel):
+    """Defines latitude, longitude and altitude using the WGS84 coordinate reference system."""
+
+    latitude: float = Field(
+        ...,
+        description="latitude in decimal degrees",
+        validation_alias=AliasChoices("latitude", AliasPath("coordinates", 0)),
+    )
+    longitude: float = Field(
+        ...,
+        description="longitude in decimal degrees",
+        validation_alias=AliasChoices("longitude", AliasPath("coordinates", 1)),
+    )
+    altitude: Optional[float] = Field(
+        None,
+        description="in meters above the WGS84 ellipsoid",
+        validation_alias=AliasChoices("altitude", AliasPath("coordinates", 2)),
+    )
+
+    @model_serializer
+    def ser_model(self) -> List[float]:
+        """serialize the whole model into a list of floats"""
+        if self.altitude:
+            return [self.latitude, self.longitude, self.altitude]
+        return [self.latitude, self.longitude]
+
+
+class GeoJSONPoint(BaseModel):
+    """GeoJsonPoint object as defined by RFC 7946."""
+
+    # for Python 3.8+ - replace "type" with "Literal['point']"
+    type_: Literal["Point"] = Field(
+        "Point", alias="type", description="Type of GeoJSON object as per RFC 5870", frozen=True
+    )
+    coordinates: WGS84Coordinate = Field(..., description="WGS84 coordinate reference system.")
+
+    @model_validator(mode="before")
+    @classmethod
+    def convert_coordinate_to_dict(cls, data: Dict[str, Any]) -> Dict[str, Any]:
+        """Converts {"coordinates": [x, y, _z]} to {"coordinates": {"coordinates": [x, y, _z]}}"""
+        # check that the length is >=2 and < 4
+        if "coordinates" not in data:
+            raise KeyError("key `coordinates` not found.")
+        if not 1 < len(data["coordinates"]) < 4:
+            raise ValueError(f"`coordinates` length must be 2 or 3 (lat, lon, <alt>), not {len(data['coordinates'])}.")
+        data["coordinates"] = {"coordinates": data["coordinates"]}
+        return data