Add option to limit the number of expanded features returned

This helps reduce the load on backend servers, as feature expansion
can quickly balloon out to a huge number of features. Default
to a very conservative expansion limit, requiring users to "opt in"
to larger limits which may be inappropriate for a service.

src/core/providers/sensorthings/qgssensorthingsprovider.cpp

@@ -394,6 +394,12 @@ QVariantMap QgsSensorThingsProviderMetadata::decodeUri( const QString &uri ) con
   {
     components.insert( QStringLiteral( "featureLimit" ), featureLimitParam );
   }
+  ok = false;
+  const int expansionLimitParam = dsUri.param( QStringLiteral( "expansionLimit" ) ).toInt( &ok );
+  if ( ok )
+  {
+    components.insert( QStringLiteral( "expansionLimit" ), expansionLimitParam );
+  }
 
   switch ( QgsWkbTypes::geometryType( dsUri.wkbType() ) )
   {
@@ -487,6 +493,12 @@ QString QgsSensorThingsProviderMetadata::encodeUri( const QVariantMap &parts ) c
   {
     dsUri.setParam( QStringLiteral( "featureLimit" ), QString::number( featureLimitParam ) );
   }
+  ok = false;
+  const int expansionLimitParam = parts.value( QStringLiteral( "expansionLimit" ) ).toInt( &ok );
+  if ( ok )
+  {
+    dsUri.setParam( QStringLiteral( "expansionLimit" ), QString::number( expansionLimitParam ) );
+  }
 
   const QString geometryType = parts.value( QStringLiteral( "geometryType" ) ).toString();
   if ( geometryType.compare( QLatin1String( "point" ), Qt::CaseInsensitive ) == 0 )

src/core/providers/sensorthings/qgssensorthingsshareddata.cpp

@@ -47,8 +47,13 @@ QgsSensorThingsSharedData::QgsSensorThingsSharedData( const QString &uri )
       expandQueryParts.append( QgsSensorThingsUtils::entityToSetString( expandToEntityType ) );
     }
   }
+  mExpansionLimit = uriParts.value( QStringLiteral( "expansionLimit" ) ).toInt();
   if ( !expandQueryParts.empty() )
+  {
     mExpandQueryString = QStringLiteral( "$expand=" ) + expandQueryParts.join( '/' );
+    if ( mExpansionLimit > 0 )
+      mExpandQueryString += QStringLiteral( "($top=%1)" ).arg( mExpansionLimit );
+  }
 
   mFields = QgsSensorThingsUtils::fieldsForExpandedEntityType( mEntityType, mExpandTo );
 

src/core/providers/sensorthings/qgssensorthingsshareddata.h

@@ -85,6 +85,7 @@ class QgsSensorThingsSharedData
     QList< Qgis::SensorThingsEntity > mExpandTo;
 
     int mFeatureLimit = 0;
+    int mExpansionLimit = 0;
     Qgis::WkbType mGeometryType = Qgis::WkbType::Unknown;
     QString mGeometryField;
     QgsFields mFields;

src/core/providers/sensorthings/qgssensorthingsutils.h

@@ -40,6 +40,9 @@ class CORE_EXPORT QgsSensorThingsUtils
     //! Default limit on number of features fetched
     static constexpr int DEFAULT_FEATURE_LIMIT = 10000; SIP_SKIP
 
+    //! Default limit on number of expanded features fetched
+    static constexpr int DEFAULT_EXPANSION_LIMIT = 100; SIP_SKIP
+
     /**
      * Converts a string value to a Qgis::SensorThingsEntity type.
      *

src/gui/providers/sensorthings/qgssensorthingssourcewidget.cpp

@@ -42,10 +42,16 @@ QgsSensorThingsSourceWidget::QgsSensorThingsSourceWidget( QWidget *parent )
   vl->addWidget( mExtentWidget );
   mExtentLimitFrame->setLayout( vl );
 
+  mSpinExpansionLimit->setEnabled( false );
+
   mSpinPageSize->setClearValue( 0, tr( "Default (%1)" ).arg( QgsSensorThingsUtils::DEFAULT_PAGE_SIZE ) );
   mSpinFeatureLimit->setClearValue( 0, tr( "No limit" ) );
+  mSpinExpansionLimit->setClearValue( 0, tr( "No limit" ) );
+  mSpinExpansionLimit->setToolTip( tr( "Limits the maximum number of related features to fetch when expanding child features" ) );
+
   // set a relatively conservative feature limit by default, to make it so they have to opt-in to shoot themselves in the foot!
   mSpinFeatureLimit->setValue( QgsSensorThingsUtils::DEFAULT_FEATURE_LIMIT );
+  mSpinExpansionLimit->setValue( QgsSensorThingsUtils::DEFAULT_EXPANSION_LIMIT );
 
   for ( Qgis::SensorThingsEntity type :
         {
@@ -72,7 +78,11 @@ QgsSensorThingsSourceWidget::QgsSensorThingsSourceWidget( QWidget *parent )
   connect( mRetrieveTypesButton, &QToolButton::clicked, this, &QgsSensorThingsSourceWidget::retrieveTypes );
   mRetrieveTypesButton->setEnabled( false );
   connect( mExtentWidget, &QgsExtentWidget::extentChanged, this, &QgsSensorThingsSourceWidget::validate );
-  connect( mComboExpandTo, qOverload< int >( &QComboBox::currentIndexChanged ), this, &QgsSensorThingsSourceWidget::validate );
+  connect( mComboExpandTo, qOverload< int >( &QComboBox::currentIndexChanged ), this, [ = ]( int )
+  {
+    mSpinExpansionLimit->setEnabled( mComboExpandTo->currentData().isValid() );
+    validate();
+  } );
   validate();
 }
 
@@ -124,6 +134,23 @@ void QgsSensorThingsSourceWidget::setSourceUri( const QString &uri )
     mSpinFeatureLimit->setValue( QgsSensorThingsUtils::DEFAULT_FEATURE_LIMIT );
   }
 
+  ok = false;
+  const int expansionLimitParam = mSourceParts.value( QStringLiteral( "expansionLimit" ) ).toInt( &ok );
+  if ( ok )
+  {
+    mSpinExpansionLimit->setValue( expansionLimitParam );
+  }
+  else if ( type != Qgis::SensorThingsEntity::Invalid )
+  {
+    // if not setting an initial uri for a new layer, use "no limit" if it's not present in the uri
+    mSpinExpansionLimit->clear();
+  }
+  else
+  {
+    // when setting an initial uri, use the default, not "no limit"
+    mSpinExpansionLimit->setValue( QgsSensorThingsUtils::DEFAULT_EXPANSION_LIMIT );
+  }
+
   const QgsRectangle bounds = mSourceParts.value( QStringLiteral( "bounds" ) ).value< QgsRectangle >();
   if ( !bounds.isNull() )
   {
@@ -226,6 +253,15 @@ QString QgsSensorThingsSourceWidget::updateUriFromGui( const QString &connection
     parts.remove( QStringLiteral( "featureLimit" ) );
   }
 
+  if ( mSpinExpansionLimit->value() > 0 )
+  {
+    parts.insert( QStringLiteral( "expansionLimit" ), QString::number( mSpinExpansionLimit->value() ) );
+  }
+  else
+  {
+    parts.remove( QStringLiteral( "expansionLimit" ) );
+  }
+
   if ( !mComboExpandTo->currentData().isValid() )
   {
     parts.remove( QStringLiteral( "expandTo" ) );

src/ui/qgssensorthingssourcewidgetbase.ui

@@ -7,7 +7,7 @@
     <x>0</x>
     <y>0</y>
     <width>537</width>
-    <height>180</height>
+    <height>213</height>
    </rect>
   </property>
   <property name="windowTitle">
@@ -26,6 +26,13 @@
    <property name="bottomMargin">
     <number>0</number>
    </property>
+   <item row="1" column="0">
+    <widget class="QLabel" name="label_2">
+     <property name="text">
+      <string>Geometry type</string>
+     </property>
+    </widget>
+   </item>
    <item row="1" column="2">
     <widget class="QToolButton" name="mRetrieveTypesButton">
      <property name="minimumSize">
@@ -53,37 +60,30 @@
      </property>
     </widget>
    </item>
-   <item row="5" column="0">
+   <item row="7" column="0">
     <widget class="QLabel" name="label_5">
      <property name="text">
       <string>Extent limit</string>
      </property>
     </widget>
    </item>
-   <item row="5" column="1" colspan="2">
+   <item row="2" column="1" colspan="2">
+    <widget class="QgsSpinBox" name="mSpinPageSize">
+     <property name="maximum">
+      <number>9999999</number>
+     </property>
+    </widget>
+   </item>
+   <item row="1" column="1">
+    <widget class="QComboBox" name="mComboGeometryType"/>
+   </item>
+   <item row="7" column="1" colspan="2">
     <widget class="QWidget" name="mExtentLimitFrame" native="true">
      <property name="focusPolicy">
       <enum>Qt::StrongFocus</enum>
      </property>
     </widget>
    </item>
-   <item row="0" column="1" colspan="2">
-    <widget class="QComboBox" name="mComboEntityType"/>
-   </item>
-   <item row="0" column="0">
-    <widget class="QLabel" name="label">
-     <property name="text">
-      <string>Entity type</string>
-     </property>
-    </widget>
-   </item>
-   <item row="3" column="0">
-    <widget class="QLabel" name="label_4">
-     <property name="text">
-      <string>Expand to</string>
-     </property>
-    </widget>
-   </item>
    <item row="4" column="0">
     <widget class="QLabel" name="label_6">
      <property name="text">
@@ -91,26 +91,9 @@
      </property>
     </widget>
    </item>
-   <item row="4" column="1" colspan="2">
-    <widget class="QgsSpinBox" name="mSpinFeatureLimit">
-     <property name="maximum">
-      <number>999999999</number>
-     </property>
-    </widget>
-   </item>
-   <item row="3" column="1" colspan="2">
+   <item row="5" column="1" colspan="2">
     <widget class="QComboBox" name="mComboExpandTo"/>
    </item>
-   <item row="1" column="0">
-    <widget class="QLabel" name="label_2">
-     <property name="text">
-      <string>Geometry type</string>
-     </property>
-    </widget>
-   </item>
-   <item row="1" column="1">
-    <widget class="QComboBox" name="mComboGeometryType"/>
-   </item>
    <item row="2" column="0">
     <widget class="QLabel" name="label_3">
      <property name="text">
@@ -118,10 +101,41 @@
      </property>
     </widget>
    </item>
-   <item row="2" column="1" colspan="2">
-    <widget class="QgsSpinBox" name="mSpinPageSize">
+   <item row="5" column="0">
+    <widget class="QLabel" name="label_4">
+     <property name="text">
+      <string>Expand to</string>
+     </property>
+    </widget>
+   </item>
+   <item row="0" column="0">
+    <widget class="QLabel" name="label">
+     <property name="text">
+      <string>Entity type</string>
+     </property>
+    </widget>
+   </item>
+   <item row="4" column="1" colspan="2">
+    <widget class="QgsSpinBox" name="mSpinFeatureLimit">
      <property name="maximum">
-      <number>9999999</number>
+      <number>999999999</number>
+     </property>
+    </widget>
+   </item>
+   <item row="0" column="1" colspan="2">
+    <widget class="QComboBox" name="mComboEntityType"/>
+   </item>
+   <item row="6" column="0">
+    <widget class="QLabel" name="label_7">
+     <property name="text">
+      <string>Expansion limit</string>
+     </property>
+    </widget>
+   </item>
+   <item row="6" column="1" colspan="2">
+    <widget class="QgsSpinBox" name="mSpinExpansionLimit">
+     <property name="maximum">
+      <number>999999999</number>
      </property>
     </widget>
    </item>
@@ -139,8 +153,9 @@
   <tabstop>mComboGeometryType</tabstop>
   <tabstop>mRetrieveTypesButton</tabstop>
   <tabstop>mSpinPageSize</tabstop>
-  <tabstop>mComboExpandTo</tabstop>
   <tabstop>mSpinFeatureLimit</tabstop>
+  <tabstop>mComboExpandTo</tabstop>
+  <tabstop>mSpinExpansionLimit</tabstop>
   <tabstop>mExtentLimitFrame</tabstop>
  </tabstops>
  <resources/>

tests/src/python/test_provider_sensorthings.py

@@ -4128,6 +4128,387 @@ class TestPyQgsSensorThingsProvider(QgisTestCase):  # , ProviderTestCase):
                  'Polygon ((103 0, 104 0, 104 1, 103 1, 103 0))'],
             )
 
+    def test_feature_expansion_with_limit(self):
+        """
+        Test a layer using feature expansion with limited child features
+        """
+        with tempfile.TemporaryDirectory() as temp_dir:
+            base_path = temp_dir.replace("\\", "/")
+            endpoint = base_path + "/fake_qgis_http_endpoint"
+            with open(sanitize(endpoint, ""), "wt", encoding="utf8") as f:
+                f.write(
+                    """
+{
+  "value": [
+    {
+      "name": "Locations",
+      "url": "endpoint/Locations"
+    }
+  ],
+  "serverSettings": {
+  }
+}""".replace(
+                        "endpoint", "http://" + endpoint
+                    )
+                )
+
+            with open(
+                sanitize(endpoint,
+                         "/Locations?$top=0&$count=true&$filter=location/type eq 'Polygon' or location/geometry/type eq 'Polygon'"),
+                "wt",
+                encoding="utf8",
+            ) as f:
+                f.write("""{"@iot.count":3,"value":[]}""")
+
+            with open(
+                sanitize(endpoint,
+                         "/Locations?$top=2&$count=false&$expand=Things/Datastreams($top=1)&$filter=location/type eq 'Polygon' or location/geometry/type eq 'Polygon'"),
+                "wt",
+                encoding="utf8",
+            ) as f:
+                f.write(
+                    """
+{
+  "value": [
+    {
+      "@iot.selfLink": "endpoint/Locations(1)",
+      "@iot.id": 1,
+      "name": "Location 1",
+      "description": "Desc 1",
+      "unitOfMeasurements": [
+          {
+            "name": "ug.m-3",
+            "symbol": "ug.m-3",
+            "definition": "http://dd.eionet.europa.eu/vocabulary/uom/concentration/ug.m-3"
+          }
+      ],
+      "observationType": "http://www.opengis.net/def/observationType/OGC-OM/2.0/OM_Measurement",
+      "multiObservationDataTypes": ["http://www.opengis.net/def/observationType/OGC-OM/2.0/OM_Measurement"],
+      "phenomenonTime": "2017-12-31T23:00:00Z/2018-01-12T04:00:00Z",
+      "resultTime": "2017-12-31T23:30:00Z/2017-12-31T23:31:00Z",
+      "properties": {
+        "owner": "owner 1"
+      },
+      "Things": [
+        {
+          "@iot.selfLink": "endpoint/Things(1)",
+          "@iot.id": 1,
+          "name": "Thing 1",
+          "description": "Description Thing 1",
+          "properties": {
+            "countryCode": "AT"
+          },
+          "Datastreams": [
+            {
+              "@iot.selfLink": "endpoint/Datastreams(45)",
+              "@iot.id": 45,
+              "name": "Datastream 45",
+              "description": "Description datastream 45",
+              "observationType": "http://www.opengis.net/def/observationType/OGC-OM/2.0/OM_Measurement",
+              "unitOfMeasurement": {
+                "name": "ug.m-3",
+                "symbol": "ug.m-3",
+                "definition": "http://dd.eionet.europa.eu/vocabulary/uom/concentration/ug.m-3"
+              },
+              "phenomenonTime": "2017-12-31T23:00:00Z/2024-03-25T04:00:00Z",
+              "properties": {
+                "owner": "someone"
+              }
+            }
+            ]
+        }
+       ],
+      "location": {
+            "type": "Polygon",
+            "coordinates": [
+              [
+                [100, 0], [101, 0], [101, 1], [100, 1], [100, 0]
+              ]
+            ]
+          },
+      "Things@iot.navigationLink": "endpoint/Locations(1)/Things",
+      "HistoricalLocations@iot.navigationLink": "endpoint/Locations(1)/HistoricalLocations"
+    },
+    {
+      "@iot.selfLink": "endpoint/Locations(2)",
+      "@iot.id": 2,
+      "name": "Location 2",
+      "description": "Desc 2",
+      "unitOfMeasurements": [
+      {
+        "name": "ug.m-3",
+        "symbol": "ug.m-3",
+        "definition": "http://dd.eionet.europa.eu/vocabulary/uom/concentration/ug.m-3"
+      }],
+      "observationType": "http://www.opengis.net/def/observationType/OGC-OM/2.0/OM_Measurement",
+      "multiObservationDataTypes": ["http://www.opengis.net/def/observationType/OGC-OM/2.0/OM_Measurement"],
+      "phenomenonTime": "2018-12-31T23:00:00Z/2019-01-12T04:00:00Z",
+      "resultTime": "2018-12-31T23:30:00Z/2018-12-31T23:31:00Z",
+      "properties": {
+        "owner": "owner 2"
+      },
+      "Things": [
+        {
+          "@iot.selfLink": "endpoint/Things(2)",
+          "@iot.id": 2,
+          "name": "Thing 2",
+          "description": "Description Thing 2",
+          "properties": {
+            "countryCode": "AT"
+          },
+          "Datastreams": [
+            {
+              "@iot.selfLink": "endpoint/Datastreams(51)",
+              "@iot.id": 51,
+              "name": "Datastream 51",
+              "description": "Description datastream 51",
+              "observationType": "http://www.opengis.net/def/observationType/OGC-OM/2.0/OM_Measurement",
+              "unitOfMeasurement": {
+                "name": "ug.m-3",
+                "symbol": "ug.m-3",
+                "definition": "http://dd.eionet.europa.eu/vocabulary/uom/concentration/ug.m-3"
+              },
+              "phenomenonTime": "2017-12-31T23:00:00Z/2024-03-25T04:00:00Z",
+              "properties": {
+                "owner": "someone"
+              }
+            }
+            ]
+        }
+       ],
+            "location": {
+            "type": "Polygon",
+            "coordinates": [
+              [
+                [102, 0], [103, 0], [103, 1], [102, 1], [102, 0]
+              ]
+            ]
+          },
+      "Things@iot.navigationLink": "endpoint/Locations(2)/Things",
+      "HistoricalLocations@iot.navigationLink": "endpoint/Locations(2)/HistoricalLocations"
+
+    }
+  ],
+  "@iot.nextLink": "endpoint/Locations?$top=2&$skip=2&$expand=Things/Datastreams($top=1)&$filter=location/type eq 'Polygon' or location/geometry/type eq 'Polygon'"
+}
+                """.replace(
+                        "endpoint", "http://" + endpoint
+                    )
+                )
+
+                with open(
+                    sanitize(endpoint,
+                             "/Locations?$top=2&$skip=2&$expand=Things/Datastreams($top=1)&$filter=location/type eq 'Polygon' or location/geometry/type eq 'Polygon'"),
+                    "wt",
+                    encoding="utf8",
+                ) as f:
+                    f.write(
+                        """
+            {
+              "value": [
+                {
+                  "@iot.selfLink": "endpoint/Locations(3)",
+                  "@iot.id": 3,
+                  "name": "Location 3",
+                  "description": "Desc 3",
+                  "unitOfMeasurements": [{
+                    "name": "ug.m-3",
+                    "symbol": "ug.m-3",
+                    "definition": "http://dd.eionet.europa.eu/vocabulary/uom/concentration/ug.m-3"
+                  }],
+                  "observationType": "http://www.opengis.net/def/observationType/OGC-OM/2.0/OM_Measurement",
+                  "multiObservationDataTypes": ["http://www.opengis.net/def/observationType/OGC-OM/2.0/OM_Measurement"],
+                  "phenomenonTime": "2020-12-31T23:00:00Z/2021-01-12T04:00:00Z",
+                  "resultTime": "2020-12-31T23:30:00Z/2020-12-31T23:31:00Z",
+                  "properties": {
+                    "owner": "owner 3"
+                  },
+                  "Things": [
+        {
+          "@iot.selfLink": "endpoint/Things(8)",
+          "@iot.id": 8,
+          "name": "Thing 8",
+          "description": "Description Thing 8",
+          "properties": {
+            "countryCode": "AT"
+          },
+          "Datastreams": [
+            {
+              "@iot.selfLink": "endpoint/Datastreams(59)",
+              "@iot.id": 59,
+              "name": "Datastream 59",
+              "description": "Description datastream 59",
+              "observationType": "http://www.opengis.net/def/observationType/OGC-OM/2.0/OM_Measurement",
+              "unitOfMeasurement": {
+                "name": "ug.m-3",
+                "symbol": "ug.m-3",
+                "definition": "http://dd.eionet.europa.eu/vocabulary/uom/concentration/ug.m-3"
+              },
+              "phenomenonTime": "2017-12-31T23:00:00Z/2024-03-25T04:00:00Z",
+              "properties": {
+                "owner": "someone"
+              }
+            }
+            ]
+        }
+       ],
+                        "location": {
+            "type": "Polygon",
+            "coordinates": [
+              [
+                [103, 0], [104, 0], [104, 1], [103, 1], [103, 0]
+              ]
+            ]
+          },
+                  "Things@iot.navigationLink": "endpoint/Locations(3)/Things",
+                  "HistoricalLocations@iot.navigationLink": "endpoint/Locations(3)/HistoricalLocations"
+                }
+              ]
+            }
+                            """.replace(
+                            "endpoint", "http://" + endpoint
+                        )
+                    )
+
+            vl = QgsVectorLayer(
+                f"url='http://{endpoint}' pageSize=2 type=MultiPolygonZ entity='Location' expansionLimit=1 expandTo='Thing,Datastream'",
+                "test",
+                "sensorthings",
+            )
+            self.assertTrue(vl.isValid())
+            # basic layer properties tests
+            self.assertEqual(vl.storageType(), "OGC SensorThings API")
+            self.assertEqual(vl.wkbType(), Qgis.WkbType.MultiPolygonZ)
+
+            self.assertEqual(vl.featureCount(), -1)
+            self.assertEqual(vl.crs().authid(), 'EPSG:4326')
+            self.assertIn("Entity Type</td><td>Location</td>",
+                          vl.htmlMetadata())
+            self.assertIn(f'href="http://{endpoint}/Locations"',
+                          vl.htmlMetadata())
+
+            self.assertEqual(
+                [f.name() for f in vl.fields()],
+                ['id', 'selfLink', 'name', 'description', 'properties',
+                 'Thing_id', 'Thing_selfLink', 'Thing_name',
+                 'Thing_description', 'Thing_properties',
+                 'Thing_Datastream_id', 'Thing_Datastream_selfLink',
+                 'Thing_Datastream_name', 'Thing_Datastream_description',
+                 'Thing_Datastream_unitOfMeasurement',
+                 'Thing_Datastream_observationType',
+                 'Thing_Datastream_properties',
+                 'Thing_Datastream_phenomenonTimeStart',
+                 'Thing_Datastream_phenomenonTimeEnd',
+                 'Thing_Datastream_resultTimeStart',
+                 'Thing_Datastream_resultTimeEnd'],
+            )
+            self.assertEqual(
+                [f.type() for f in vl.fields()],
+                [
+                    QVariant.String,
+                    QVariant.String,
+                    QVariant.String,
+                    QVariant.String,
+                    QVariant.Map,
+                    QVariant.String,
+                    QVariant.String,
+                    QVariant.String,
+                    QVariant.String,
+                    QVariant.Map,
+                    QVariant.String,
+                    QVariant.String,
+                    QVariant.String,
+                    QVariant.String,
+                    QVariant.Map,
+                    QVariant.String,
+                    QVariant.Map,
+                    QVariant.DateTime,
+                    QVariant.DateTime,
+                    QVariant.DateTime,
+                    QVariant.DateTime,
+                ],
+            )
+
+            # test retrieving all features from layer
+            features = list(vl.getFeatures())
+            self.assertEqual([f.id() for f in features],
+                             [0, 1, 2])
+            self.assertEqual([f["id"] for f in features],
+                             ["1", "2", "3"])
+            self.assertEqual(
+                [f["selfLink"][-13:] for f in features],
+                ["/Locations(1)", "/Locations(2)",
+                 "/Locations(3)"],
+            )
+            self.assertEqual(
+                [f["name"] for f in features],
+                ["Location 1", "Location 2",
+                 "Location 3"],
+            )
+            self.assertEqual(
+                [f["description"] for f in features],
+                ["Desc 1", "Desc 2",
+                 "Desc 3"]
+            )
+            self.assertEqual(
+                [f["properties"] for f in features],
+                [{'owner': 'owner 1'},
+                 {'owner': 'owner 2'},
+                 {'owner': 'owner 3'}]
+            )
+            self.assertEqual(
+                [f["Thing_id"] for f in features],
+                ['1', '2', '8']
+            )
+            self.assertEqual(
+                [f["Thing_selfLink"][-10:] for f in features],
+                ['/Things(1)', '/Things(2)', '/Things(8)']
+            )
+            self.assertEqual(
+                [f["Thing_name"] for f in features],
+                ['Thing 1', 'Thing 2', 'Thing 8']
+            )
+            self.assertEqual(
+                [f["Thing_description"] for f in features],
+                ['Description Thing 1', 'Description Thing 2',
+                 'Description Thing 8']
+            )
+            self.assertEqual(
+                [f["Thing_properties"] for f in features],
+                [{'countryCode': 'AT'}, {'countryCode': 'AT'},
+                 {'countryCode': 'AT'}]
+            )
+            self.assertEqual(
+                [f["Thing_Datastream_id"] for f in features],
+                ['45', '51', '59']
+            )
+            self.assertEqual(
+                [f["Thing_Datastream_selfLink"][-16:] for f in features],
+                ['/Datastreams(45)', '/Datastreams(51)',
+                 '/Datastreams(59)']
+            )
+            self.assertEqual(
+                [f["Thing_Datastream_name"] for f in features],
+                ['Datastream 45', 'Datastream 51', 'Datastream 59']
+            )
+            self.assertEqual(
+                [f["Thing_Datastream_description"] for f in features],
+                ['Description datastream 45', 'Description datastream 51',
+                 'Description datastream 59']
+            )
+            self.assertEqual(
+                [f["Thing_Datastream_properties"] for f in features],
+                [{'owner': 'someone'}, {'owner': 'someone'},
+                 {'owner': 'someone'}]
+            )
+
+            self.assertEqual(
+                [f.geometry().asWkt() for f in features],
+                ['Polygon ((100 0, 101 0, 101 1, 100 1, 100 0))',
+                 'Polygon ((102 0, 103 0, 103 1, 102 1, 102 0))',
+                 'Polygon ((103 0, 104 0, 104 1, 103 1, 103 0))'],
+            )
+
     def testDecodeUri(self):
         """
         Test decoding a SensorThings uri
@@ -4222,7 +4603,7 @@ class TestPyQgsSensorThingsProvider(QgisTestCase):  # , ProviderTestCase):
             },
         )
 
-        uri = "url='https://sometest.com/api' type=MultiPolygonZ authcfg='abc' expandTo='Thing,Datastream' entity='Location'"
+        uri = "url='https://sometest.com/api' type=MultiPolygonZ authcfg='abc' expandTo='Thing,Datastream' expansionLimit=30 entity='Location'"
         parts = QgsProviderRegistry.instance().decodeUri("sensorthings", uri)
         self.assertEqual(
             parts,
@@ -4231,6 +4612,7 @@ class TestPyQgsSensorThingsProvider(QgisTestCase):  # , ProviderTestCase):
                 "entity": "Location",
                 "geometryType": "polygon",
                 "authcfg": "abc",
+                'expansionLimit': 30,
                 "expandTo": ['Thing', 'Datastream']
             },
         )
@@ -4332,12 +4714,13 @@ class TestPyQgsSensorThingsProvider(QgisTestCase):  # , ProviderTestCase):
             "authcfg": "aaaaa",
             "entity": "location",
             "geometryType": "polygon",
-            "expandTo": ["Thing", "Datastream"]
+            "expandTo": ["Thing", "Datastream"],
+            'expansionLimit': 30
         }
         uri = QgsProviderRegistry.instance().encodeUri("sensorthings", parts)
         self.assertEqual(
             uri,
-            "authcfg=aaaaa type=MultiPolygonZ entity='Location' expandTo='Thing,Datastream' url='http://blah.com'",
+            "authcfg=aaaaa type=MultiPolygonZ entity='Location' expandTo='Thing,Datastream' expansionLimit='30' url='http://blah.com'",
         )