Add get (by path) method for complex objects.

Author: chsou

c8y_api/model/_base.py

@@ -400,6 +400,30 @@ def __iadd__(self, other):
     def __contains__(self, name):
         return name in self.fragments
 
+    def get(self, path: str, default=None):
+        """Get a fragment/value by path.
+
+        Args:
+            path (str): A fragment/value path in dot notation, e.g.
+                "c8y_Firmware.version"
+            default: Sensible default if the path is not defined.
+
+        Returns:
+            The fragment/value specified via the path or the default value
+            if the path is not defined.
+        """
+        segments = path.split('.')
+        value = self
+        for segment in segments:
+            if segment in value:
+                value = value[segment]
+                continue
+            if hasattr(value, segment):
+                return value.__getattribute__(segment)
+            else:
+                return default
+        return value
+
     @deprecated
     def set_attribute(self, name, value):
         # pylint: disable=missing-function-docstring

tests/model/test_base.py

@@ -232,6 +232,23 @@ def test_complexobject_instantiation_and_formatting():
     assert obj._to_json(only_updated=True) == expected_diff_json
 
 
+def test_complexobject_get():
+
+    obj = ComplexTestObject(
+        field='field value',
+        fixed_field=123,
+        c8y_simple=True,
+        c8y_complex={'a': 'valueA', 'b': 'valueB'},
+        additionalField=True,
+        additionalFragment={'value1': "A", 'value2': "B"}
+    )
+
+    assert obj.get('field') == obj.field
+    assert obj.get('c8y_complex.a') == obj.c8y_complex.a
+    assert obj.get('not') is None
+    assert obj.get('not', 'default') == 'default'
+
+
 @pytest.mark.parametrize('page_size, num_all, limit, expected', [
     (10, 100, 100, 100),  # exact
     (10, 200, 100, 100),  # limit hit