Added method for translating between generic geometry name and the …

…name of the actual geometry column in the postgres DB (#1453)

pygeoapi/provider/postgresql.py

@@ -55,6 +55,7 @@
 from geoalchemy2.functions import ST_MakeEnvelope
 from geoalchemy2.shape import to_shape
 from pygeofilter.backends.sqlalchemy.evaluate import to_filter
+import pygeofilter.ast
 import pyproj
 import shapely
 from sqlalchemy import create_engine, MetaData, PrimaryKeyConstraint, asc, desc
@@ -138,7 +139,8 @@ def query(self, offset=0, limit=10, resulttype='results',
 
         LOGGER.debug('Preparing filters')
         property_filters = self._get_property_filters(properties)
-        cql_filters = self._get_cql_filters(filterq)
+        modified_filterq = self._modify_pygeofilter(filterq)
+        cql_filters = self._get_cql_filters(modified_filterq)
         bbox_filter = self._get_bbox_filter(bbox)
         order_by_clauses = self._get_order_by_clauses(sortby, self.table_model)
         selected_properties = self._select_properties_clause(select_properties,
@@ -495,3 +497,40 @@ def _get_crs_transform(self, crs_transform_spec=None):
         else:
             crs_transform = None
         return crs_transform
+
+    def _modify_pygeofilter(
+            self,
+            ast_tree: pygeofilter.ast.Node,
+    ) -> pygeofilter.ast.Node:
+        """
+        Prepare the input pygeofilter for querying the database.
+
+        Returns a new ``pygeofilter.ast.Node`` object that can be used for
+        querying the database.
+        """
+        new_tree = deepcopy(ast_tree)
+        _inplace_replace_geometry_filter_name(new_tree, self.geom)
+        return new_tree
+
+
+def _inplace_replace_geometry_filter_name(
+        node: pygeofilter.ast.Node,
+        geometry_column_name: str
+):
+    """Recursively traverse node tree and rename nodes of type ``Attribute``.
+
+    Nodes of type ``Attribute`` named ``geometry`` are renamed to the value of
+    the ``geometry_column_name`` parameter.
+    """
+    try:
+        sub_nodes = node.get_sub_nodes()
+    except AttributeError:
+        pass
+    else:
+        for sub_node in sub_nodes:
+            is_attribute_node = isinstance(sub_node, pygeofilter.ast.Attribute)
+            if is_attribute_node and sub_node.name == "geometry":
+                sub_node.name = geometry_column_name
+            else:
+                _inplace_replace_geometry_filter_name(
+                    sub_node, geometry_column_name)

tests/test_postgresql_provider.py

@@ -44,7 +44,9 @@
 import pyproj
 from http import HTTPStatus
 
+import pygeofilter.ast
 from pygeofilter.parsers.ecql import parse
+from pygeofilter.values import Geometry
 
 from pygeoapi.api import API
 
@@ -748,3 +750,69 @@ def test_get_collection_items_postgresql_automap_naming_conflicts(pg_api_):
     assert code == HTTPStatus.OK
     features = json.loads(response).get('features')
     assert len(features) == 0
+
+
+@pytest.mark.parametrize('original_filter, expected', [
+    pytest.param(
+        "INTERSECTS(geometry, POINT(1 1))",
+        pygeofilter.ast.GeometryIntersects(
+            pygeofilter.ast.Attribute(name='custom_geom_name'),
+            Geometry({'type': 'Point', 'coordinates': (1, 1)})
+        ),
+        id='unnested-geometry'
+    ),
+    pytest.param(
+        "some_attribute = 10 AND INTERSECTS(geometry, POINT(1 1))",
+        pygeofilter.ast.And(
+            pygeofilter.ast.Equal(
+                pygeofilter.ast.Attribute(name='some_attribute'), 10),
+            pygeofilter.ast.GeometryIntersects(
+                pygeofilter.ast.Attribute(name='custom_geom_name'),
+                Geometry({'type': 'Point', 'coordinates': (1, 1)})
+            ),
+        ),
+        id='nested-geometry'
+    ),
+    pytest.param(
+        "(some_attribute = 10 AND INTERSECTS(geometry, POINT(1 1))) OR "
+        "DWITHIN(geometry, POINT(2 2), 10, meters)",
+        pygeofilter.ast.Or(
+            pygeofilter.ast.And(
+                pygeofilter.ast.Equal(
+                    pygeofilter.ast.Attribute(name='some_attribute'), 10),
+                pygeofilter.ast.GeometryIntersects(
+                    pygeofilter.ast.Attribute(name='custom_geom_name'),
+                    Geometry({'type': 'Point', 'coordinates': (1, 1)})
+                ),
+            ),
+            pygeofilter.ast.DistanceWithin(
+                pygeofilter.ast.Attribute(name='custom_geom_name'),
+                Geometry({'type': 'Point', 'coordinates': (2, 2)}),
+                distance=10,
+                units='meters',
+            )
+        ),
+        id='complex-filter'
+    ),
+])
+def test_modify_pygeofilter(original_filter, expected):
+
+    class _CustomPostgreSqlProvider(PostgreSQLProvider):
+        """This is a subclass of the original PostgreSQLProvider.
+
+        The current test is only interested in verifying the correctness of
+        the logic that modifies the parsed filter. As such, in order
+        to simplify instantiating the postgresql pygeoapi provider, and
+        in order to avoid dealing with mocking out the sqlalchemy table
+        reflection mechanism, this class overrides the __init__() method
+        and can be used to test the implementation of the base class'
+        `self._modify_pygeofilter()` method, which is really all we want
+        to test here.
+        """
+        def __init__(self):
+            self.geom = 'custom_geom_name'
+
+    provider = _CustomPostgreSqlProvider()
+    parsed_filter = parse(original_filter)
+    result = provider._modify_pygeofilter(parsed_filter)
+    assert result == expected