feat: implement optional count for postgresql provider

This work has been done to allow the result count to be enabled or disabled for the PostgreSQL provider. By disabling the count you can get improved performance on large datasets but on smaller datasets this is unlikely to have any affect.

Author: mdearos

docs/source/publishing/ogcapi-features.rst

@@ -625,6 +625,7 @@ Must have PostGIS installed.
          id_field: osm_id
          table: hotosm_bdi_waterways
          geom_field: foo_geom
+         count: true # Optional; Default true; Enable/disable count for improved performance.
 
 A number of database connection options can be also configured in the provider in order to adjust properly the sqlalchemy engine client.
 These are optional and if not specified, the default from the engine will be used. Please see also `SQLAlchemy docs <https://docs.sqlalchemy.org/en/14/core/engines.html#custom-dbapi-connect-arguments-on-connect-routines>`_.
@@ -662,6 +663,7 @@ These are optional and if not specified, the default from the engine will be use
          id_field: osm_id
          table: hotosm_bdi_waterways
          geom_field: foo_geom
+         count: true # Optional; Default true; Enable/disable count for improved performance.
 
 The PostgreSQL provider is also able to connect to Cloud SQL databases.
 
@@ -677,6 +679,7 @@ The PostgreSQL provider is also able to connect to Cloud SQL databases.
              password: postgres
          id_field: id
          table: states
+         count: true # Optional; Default true; Enable/disable count for improved performance.
 
 This is what a configuration for `Google Cloud SQL`_ connection looks like. The ``host``
 block contains the necessary socket connection information.

pygeoapi/provider/sql.py

@@ -128,7 +128,7 @@ def __init__(
         self.id_field = provider_def['id_field']
         self.geom = provider_def.get('geom_field', 'geom')
         self.driver_name = driver_name
-        self.count = str2bool(provider_def.get('count', True))
+        self.count = str(provider_def.get('count', 'true')).lower() == 'true'
 
         LOGGER.debug(f'Name: {self.name}')
         LOGGER.debug(f'Table: {self.table}')
@@ -214,18 +214,18 @@ def query(
                 .options(selected_properties)
             )
 
-            matched = results.count()
-
-            LOGGER.debug(f'Found {matched} result(s)')
-
             LOGGER.debug('Preparing response')
             response = {
                 'type': 'FeatureCollection',
                 'features': [],
-                'numberMatched': matched,
                 'numberReturned': 0
             }
 
+            if self.count or resulttype == 'hits':
+                matched = results.count()
+                response['numberMatched'] = matched
+                LOGGER.debug(f'Found {matched} result(s)')
+
             if resulttype == 'hits' or not results:
                 return response
 

tests/provider/test_postgresql_provider.py

@@ -85,7 +85,8 @@ def config():
         },
         'id_field': 'osm_id',
         'table': 'hotosm_bdi_waterways',
-        'geom_field': 'foo_geom'
+        'geom_field': 'foo_geom',
+        'count': 'true'
     }
 
 
@@ -908,3 +909,70 @@ def test_transaction_create_handles_invalid_input_data(pg_api_, data):
     headers, code, content = manage_collection_item(
         pg_api_, req, action='create', dataset='hot_osm_waterways')
     assert 'generic error' in content
+
+
+def test_provider_count_default_value(config):
+    # Arrange
+    provider = PostgreSQLProvider(config)
+
+    # Act
+    results = provider.query()
+
+    # Assert
+    assert results['numberMatched'] == 14776
+
+
+@pytest.mark.parametrize("count_value", [
+    ('true'),
+    ('TRUE')
+])
+def test_provider_count_true(config, count_value):
+    # Arrange
+    config['count'] = count_value
+    provider = PostgreSQLProvider(config)
+
+    # Act
+    results = provider.query()
+
+    # Assert
+    assert results['numberMatched'] == 14776
+
+
+@pytest.mark.parametrize("count_value", [
+    ('false'),
+    ('FALSE')
+])
+def test_provider_count_false(config, count_value):
+    # Arrange
+    config['count'] = count_value
+    provider = PostgreSQLProvider(config)
+
+    # Act
+    results = provider.query()
+
+    # Assert
+    assert 'numberMatched' not in results
+
+
+def test_provider_count_false_with_resulttype_hits(config):
+    # Arrange
+    config['count'] = 'false'
+    provider = PostgreSQLProvider(config)
+
+    # Act
+    results = provider.query(resulttype="hits")
+
+    # Assert
+    assert results['numberMatched'] == 14776
+
+
+def test_provider_count_number_string(config):
+    # Arrange
+    config['count'] = '1'
+    provider = PostgreSQLProvider(config)
+
+    # Act
+    results = provider.query()
+
+    # Assert
+    assert 'numberMatched' not in results