Merge pull request #38320 from qgis-bot/backport-38257-to-release-3_14

[Backport release-3_14] Bugfix gh26189 virtual layers subset string
qgis · Aug 17, 2020 · af1f013 · af1f013
2 parents 34ec910 + 1026624
commit af1f013
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Showing 5 changed files with 158 additions and 5 deletions.
diff --git a/python/core/auto_generated/qgsvirtuallayerdefinition.sip.in b/python/core/auto_generated/qgsvirtuallayerdefinition.sip.in
@@ -94,6 +94,7 @@ uid=column_name                         is the name of a column with unique inte
 nogeometry                              is a flag to force the layer to be a non-geometry layer
 query=sql                               represents the SQL query. Must be URL-encoded
 field=column_name:[int|real|text]       represents a field with its name and its type
+subsetstring=subset_string              represents the subsetstring
 %End
 
     QUrl toUrl() const;
@@ -226,6 +227,20 @@ Convenience method to test whether the definition has referenced (live) layers
     bool hasDefinedGeometry() const;
 %Docstring
 Convenient method to test if the geometry is defined (not NoGeometry and not Unknown)
+%End
+
+    QString subsetString() const;
+%Docstring
+Returns the subset string.
+
+.. versionadded:: 3.16
+%End
+
+    void setSubsetString( const QString &subsetString );
+%Docstring
+Sets the ``subsetString``
+
+.. versionadded:: 3.16
 %End
 
 };

diff --git a/src/core/qgsvirtuallayerdefinition.cpp b/src/core/qgsvirtuallayerdefinition.cpp
@@ -162,6 +162,10 @@ QgsVirtualLayerDefinition QgsVirtualLayerDefinition::fromUrl( const QUrl &url )
     {
       def.setLazy( true );
     }
+    else if ( key == QLatin1String( "subsetstring" ) )
+    {
+      def.setSubsetString( QUrl::fromPercentEncoding( value.toUtf8() ) );
+    }
   }
   def.setFields( fields );
 
@@ -302,6 +306,11 @@ QUrl QgsVirtualLayerDefinition::toUrl() const
     urlQuery.addQueryItem( QStringLiteral( "lazy" ), QString() );
   }
 
+  if ( ! subsetString().isEmpty() )
+  {
+    urlQuery.addQueryItem( QStringLiteral( "subsetstring" ), QUrl::toPercentEncoding( subsetString() ) );
+  }
+
   url.setQuery( urlQuery );
 
   return url;
@@ -347,3 +356,13 @@ bool QgsVirtualLayerDefinition::hasReferencedLayers() const
   }
   return false;
 }
+
+QString QgsVirtualLayerDefinition::subsetString() const
+{
+  return mSubsetString;
+}
+
+void QgsVirtualLayerDefinition::setSubsetString( const QString &subsetString )
+{
+  mSubsetString = subsetString;
+}
diff --git a/src/core/qgsvirtuallayerdefinition.h b/src/core/qgsvirtuallayerdefinition.h
@@ -95,6 +95,7 @@ class CORE_EXPORT QgsVirtualLayerDefinition
      * nogeometry                              is a flag to force the layer to be a non-geometry layer
      * query=sql                               represents the SQL query. Must be URL-encoded
      * field=column_name:[int|real|text]       represents a field with its name and its type
+     * subsetstring=subset_string              represents the subsetstring
      */
     static QgsVirtualLayerDefinition fromUrl( const QUrl &url );
 
@@ -185,6 +186,18 @@ class CORE_EXPORT QgsVirtualLayerDefinition
       return geometryWkbType() != QgsWkbTypes::NoGeometry && geometryWkbType() != QgsWkbTypes::Unknown;
     }
 
+    /**
+     * Returns the subset string.
+     * \since QGIS 3.16
+     */
+    QString subsetString() const;
+
+    /**
+     * Sets the \a subsetString
+     * \since QGIS 3.16
+     */
+    void setSubsetString( const QString &subsetString );
+
   private:
     SourceLayers mSourceLayers;
     QString mQuery;
@@ -195,6 +208,7 @@ class CORE_EXPORT QgsVirtualLayerDefinition
     bool mLazy = false;
     QgsWkbTypes::Type mGeometryWkbType = QgsWkbTypes::Unknown;
     long mGeometrySrid = 0;
+    QString mSubsetString;
 };
 
 // clazy:excludeall=qstring-allocations

diff --git a/src/providers/virtual/qgsvirtuallayerprovider.cpp b/src/providers/virtual/qgsvirtuallayerprovider.cpp
@@ -76,6 +76,8 @@ QgsVirtualLayerProvider::QgsVirtualLayerProvider( QString const &uri, const QgsD
   {
     mDefinition = QgsVirtualLayerDefinition::fromUrl( url );
 
+    mSubset = mDefinition.subsetString();
+
     if ( !mDefinition.isLazy() )
     {
       reloadData();
@@ -205,6 +207,8 @@ bool QgsVirtualLayerProvider::openIt()
     mTableName = VIRTUAL_LAYER_QUERY_VIEW;
   }
 
+  mSubset = mDefinition.subsetString();
+
   return true;
 }
 
@@ -523,6 +527,10 @@ bool QgsVirtualLayerProvider::setSubsetString( const QString &subset, bool updat
   if ( updateFeatureCount )
     updateStatistics();
 
+  mDefinition.setSubsetString( subset );
+
+  setDataSourceUri( mDefinition.toString() );
+
   emit dataChanged();
 
   return true;

diff --git a/tests/src/python/test_provider_virtual.py b/tests/src/python/test_provider_virtual.py
@@ -23,14 +23,16 @@
                        QgsVirtualLayerDefinitionUtils,
                        QgsWkbTypes,
                        QgsProject,
-                       QgsVectorLayerJoinInfo
+                       QgsVectorLayerJoinInfo,
+                       QgsVectorFileWriter,
+                       QgsVirtualLayerDefinitionUtils
                        )
 
 from qgis.testing import start_app, unittest
 from utilities import unitTestDataPath
 
 from providertestbase import ProviderTestCase
-from qgis.PyQt.QtCore import QUrl, QVariant
+from qgis.PyQt.QtCore import QUrl, QVariant, QTemporaryDir
 
 from qgis.utils import spatialite_connect
 
@@ -833,15 +835,13 @@ def test_relative_paths(self):
         QgsProject.instance().setFileName(temp)
         QgsProject.instance().write()
 
-        QgsProject.instance().removeAllMapLayers()
         QgsProject.instance().clear()
         self.assertEqual(len(QgsProject.instance().mapLayers()), 0)
 
         # Check that virtual layer source is stored with relative path
         percent_path_relative = toPercent("./france_parts.shp")
         with open(temp, 'r') as f:
             content = ''.join(f.readlines())
-            print(content)
             self.assertTrue('<datasource>?layer=ogr:{}'.format(percent_path_relative) in content)
 
         # Check that project is correctly re-read with all layers
@@ -854,7 +854,6 @@ def test_relative_paths(self):
         QgsProject.instance().writeEntryBool('Paths', '/Absolute', True)
         QgsProject.instance().write()
 
-        QgsProject.instance().removeAllMapLayers()
         QgsProject.instance().clear()
         self.assertEqual(len(QgsProject.instance().mapLayers()), 0)
 
@@ -1164,6 +1163,104 @@ def test_filter_rect_precise(self):
 
         QgsProject.instance().removeMapLayer(pl)
 
+    def test_subset_string(self):
+        """Test that subset strings are stored and restored correctly from the project
+        See: GH #26189
+        """
+
+        project = QgsProject.instance()
+        project.clear()
+        data_layer = QgsVectorLayer('Point?crs=epsg:4326&field=fid:integer&field=value:integer&field=join_pk:integer', 'data', 'memory')
+        join_layer = QgsVectorLayer('NoGeometry?field=fid:integer&field=value:string', 'join', 'memory')
+        tempdir = QTemporaryDir()
+        gpkg_path = os.path.join(tempdir.path(), 'test_subset.gpkg')
+        project_path = os.path.join(tempdir.path(), 'test_subset.qgs')
+        self.assertTrue(data_layer.isValid())
+        self.assertTrue(join_layer.isValid())
+        self.assertFalse(join_layer.isSpatial())
+
+        f = QgsFeature(data_layer.fields())
+        f.setAttributes([1, 20, 2])
+        f.setGeometry(QgsGeometry.fromWkt('point(9 45'))
+        self.assertTrue(data_layer.dataProvider().addFeature(f))
+
+        f = QgsFeature(data_layer.fields())
+        f.setAttributes([2, 10, 1])
+        f.setGeometry(QgsGeometry.fromWkt('point(9 45'))
+        self.assertTrue(data_layer.dataProvider().addFeature(f))
+
+        options = QgsVectorFileWriter.SaveVectorOptions()
+        options.driverName = 'GPKG'
+        options.actionOnExistingFile = QgsVectorFileWriter.CreateOrOverwriteFile
+        options.layerName = 'data'
+
+        _, _ = QgsVectorFileWriter.writeAsVectorFormatV2(
+            data_layer,
+            gpkg_path,
+            data_layer.transformContext(),
+            options
+        )
+
+        f = QgsFeature(join_layer.fields())
+        f.setAttributes([1, "ten"])
+        self.assertTrue(join_layer.dataProvider().addFeature(f))
+        f.setAttributes([2, "twenty"])
+        self.assertTrue(join_layer.dataProvider().addFeature(f))
+
+        options.layerName = 'join'
+        options.actionOnExistingFile = QgsVectorFileWriter.CreateOrOverwriteLayer
+
+        _, _ = QgsVectorFileWriter.writeAsVectorFormatV2(
+            join_layer,
+            gpkg_path,
+            join_layer.transformContext(),
+            options
+        )
+
+        gpkg_join_layer = QgsVectorLayer(gpkg_path + '|layername=join', 'join', 'ogr')
+        gpkg_data_layer = QgsVectorLayer(gpkg_path + '|layername=data', 'data', 'ogr')
+
+        self.assertTrue(gpkg_join_layer.isValid())
+        self.assertTrue(gpkg_data_layer.isValid())
+        self.assertEqual(gpkg_data_layer.featureCount(), 2)
+        self.assertEqual(gpkg_join_layer.featureCount(), 2)
+
+        self.assertTrue(project.addMapLayers([gpkg_data_layer, gpkg_join_layer]))
+
+        joinInfo = QgsVectorLayerJoinInfo()
+        joinInfo.setTargetFieldName("join_pk")
+        joinInfo.setJoinLayer(gpkg_join_layer)
+        joinInfo.setJoinFieldName("fid")
+        gpkg_data_layer.addJoin(joinInfo)
+        self.assertEqual(len(gpkg_data_layer.fields()), 4)
+
+        self.assertTrue(project.write(project_path))
+
+        # Reload project
+        self.assertTrue(project.read(project_path))
+        gpkg_data_layer = project.mapLayersByName('data')[0]
+        gpkg_join_layer = project.mapLayersByName('join')[0]
+
+        self.assertEqual(gpkg_data_layer.vectorJoins()[0], joinInfo)
+
+        # Now set a subset filter -> virtual layer
+        virtual_def = QgsVirtualLayerDefinitionUtils.fromJoinedLayer(gpkg_data_layer)
+        virtual = QgsVectorLayer(virtual_def.toString(), "virtual_data", "virtual")
+        self.assertTrue(virtual.isValid())
+        project.addMapLayers([virtual])
+
+        self.assertEqual(virtual.featureCount(), 2)
+        self.assertTrue(virtual.setSubsetString('"join_value" = \'twenty\''))
+        self.assertEqual(virtual.featureCount(), 1)
+        self.assertEqual([f.attributes() for f in virtual.getFeatures()], [[1, 20, 2, 'twenty']])
+
+        # Store and reload the project
+        self.assertTrue(project.write(project_path))
+        self.assertTrue(project.read(project_path))
+        gpkg_virtual_layer = project.mapLayersByName('virtual_data')[0]
+        self.assertEqual(gpkg_virtual_layer.featureCount(), 1)
+        self.assertEqual(gpkg_virtual_layer.subsetString(), '"join_value" = \'twenty\'')
+
 
 if __name__ == '__main__':
     unittest.main()