Allow selection of a subset of fields to keep for hub lines algorithm

python/plugins/processing/tests/testdata/expected/hub_lines_field_subset.gml

@@ -0,0 +1,70 @@
+<?xml version="1.0" encoding="utf-8" ?>
+<ogr:FeatureCollection
+     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+     xsi:schemaLocation="http://ogr.maptools.org/ hub_lines_field_subset.xsd"
+     xmlns:ogr="http://ogr.maptools.org/"
+     xmlns:gml="http://www.opengis.net/gml">
+  <gml:boundedBy>
+    <gml:Box>
+      <gml:coord><gml:X>1</gml:X><gml:Y>-4.1675</gml:Y></gml:coord>
+      <gml:coord><gml:X>7</gml:X><gml:Y>3.8825</gml:Y></gml:coord>
+    </gml:Box>
+  </gml:boundedBy>
+                                                                                                                                                     
+  <gml:featureMember>
+    <ogr:hub_lines_field_subset fid="hub_lines_field_subset.0">
+      <ogr:geometryProperty><gml:LineString srsName="EPSG:4326"><gml:coordinates>1,1 5.07625,-2.1725</gml:coordinates></gml:LineString></ogr:geometryProperty>
+      <ogr:id>1</ogr:id>
+      <ogr:id2>2</ogr:id2>
+      <ogr:name>point 1</ogr:name>
+    </ogr:hub_lines_field_subset>
+  </gml:featureMember>
+  <gml:featureMember>
+    <ogr:hub_lines_field_subset fid="hub_lines_field_subset.1">
+      <ogr:geometryProperty><gml:LineString srsName="EPSG:4326"><gml:coordinates>3,3 5.82,3.8825</gml:coordinates></gml:LineString></ogr:geometryProperty>
+      <ogr:id>2</ogr:id>
+      <ogr:id2>1</ogr:id2>
+      <ogr:name>point 2</ogr:name>
+    </ogr:hub_lines_field_subset>
+  </gml:featureMember>
+  <gml:featureMember>
+    <ogr:hub_lines_field_subset fid="hub_lines_field_subset.2">
+      <ogr:geometryProperty><gml:LineString srsName="EPSG:4326"><gml:coordinates>2,2 1.62,1.4675</gml:coordinates></gml:LineString></ogr:geometryProperty>
+      <ogr:id>3</ogr:id>
+      <ogr:id2>0</ogr:id2>
+      <ogr:name>point 3</ogr:name>
+    </ogr:hub_lines_field_subset>
+  </gml:featureMember>
+  <gml:featureMember>
+    <ogr:hub_lines_field_subset fid="hub_lines_field_subset.3">
+      <ogr:geometryProperty><gml:LineString srsName="EPSG:4326"><gml:coordinates>5,2 6.68625,1.23125</gml:coordinates></gml:LineString></ogr:geometryProperty>
+      <ogr:id>4</ogr:id>
+      <ogr:id2>2</ogr:id2>
+      <ogr:name>point 4</ogr:name>
+    </ogr:hub_lines_field_subset>
+  </gml:featureMember>
+  <gml:featureMember>
+    <ogr:hub_lines_field_subset fid="hub_lines_field_subset.4">
+      <ogr:geometryProperty><gml:LineString srsName="EPSG:4326"><gml:coordinates>5,2 1.27875,-3.66875</gml:coordinates></gml:LineString></ogr:geometryProperty>
+      <ogr:id>4</ogr:id>
+      <ogr:id2>2</ogr:id2>
+      <ogr:name>point 4a</ogr:name>
+    </ogr:hub_lines_field_subset>
+  </gml:featureMember>
+  <gml:featureMember>
+    <ogr:hub_lines_field_subset fid="hub_lines_field_subset.5">
+      <ogr:geometryProperty><gml:LineString srsName="EPSG:4326"><gml:coordinates>5,2 3.81625,-4.1675</gml:coordinates></gml:LineString></ogr:geometryProperty>
+      <ogr:id>4</ogr:id>
+      <ogr:id2>2</ogr:id2>
+      <ogr:name>point 4b</ogr:name>
+    </ogr:hub_lines_field_subset>
+  </gml:featureMember>
+  <gml:featureMember>
+    <ogr:hub_lines_field_subset fid="hub_lines_field_subset.6">
+      <ogr:geometryProperty><gml:LineString srsName="EPSG:4326"><gml:coordinates>7,-1 6.82625,-2.79375</gml:coordinates></gml:LineString></ogr:geometryProperty>
+      <ogr:id>8</ogr:id>
+      <ogr:id2>0</ogr:id2>
+      <ogr:name>point 8</ogr:name>
+    </ogr:hub_lines_field_subset>
+  </gml:featureMember>
+</ogr:FeatureCollection>

python/plugins/processing/tests/testdata/expected/hub_lines_field_subset.xsd

@@ -0,0 +1,44 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<xs:schema targetNamespace="http://ogr.maptools.org/" xmlns:ogr="http://ogr.maptools.org/" xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:gml="http://www.opengis.net/gml" elementFormDefault="qualified" version="1.0">
+<xs:import namespace="http://www.opengis.net/gml" schemaLocation="http://schemas.opengis.net/gml/2.1.2/feature.xsd"/>
+<xs:element name="FeatureCollection" type="ogr:FeatureCollectionType" substitutionGroup="gml:_FeatureCollection"/>
+<xs:complexType name="FeatureCollectionType">
+  <xs:complexContent>
+    <xs:extension base="gml:AbstractFeatureCollectionType">
+      <xs:attribute name="lockId" type="xs:string" use="optional"/>
+      <xs:attribute name="scope" type="xs:string" use="optional"/>
+    </xs:extension>
+  </xs:complexContent>
+</xs:complexType>
+<xs:element name="hub_lines_field_subset" type="ogr:hub_lines_field_subset_Type" substitutionGroup="gml:_Feature"/>
+<xs:complexType name="hub_lines_field_subset_Type">
+  <xs:complexContent>
+    <xs:extension base="gml:AbstractFeatureType">
+      <xs:sequence>
+        <xs:element name="geometryProperty" type="gml:LineStringPropertyType" nillable="true" minOccurs="0" maxOccurs="1"/>
+        <xs:element name="id" nillable="true" minOccurs="0" maxOccurs="1">
+          <xs:simpleType>
+            <xs:restriction base="xs:integer">
+              <xs:totalDigits value="10"/>
+            </xs:restriction>
+          </xs:simpleType>
+        </xs:element>
+        <xs:element name="id2" nillable="true" minOccurs="0" maxOccurs="1">
+          <xs:simpleType>
+            <xs:restriction base="xs:integer">
+              <xs:totalDigits value="10"/>
+            </xs:restriction>
+          </xs:simpleType>
+        </xs:element>
+        <xs:element name="name" nillable="true" minOccurs="0" maxOccurs="1">
+          <xs:simpleType>
+            <xs:restriction base="xs:string">
+              <xs:maxLength value="8"/>
+            </xs:restriction>
+          </xs:simpleType>
+        </xs:element>
+      </xs:sequence>
+    </xs:extension>
+  </xs:complexContent>
+</xs:complexType>
+</xs:schema>

python/plugins/processing/tests/testdata/qgis_algorithm_tests.yaml

@@ -2500,6 +2500,27 @@ tests:
             fid: skip
             fid_2: skip
 
+  - algorithm: native:hublines
+    name: Hub lines subset of fields
+    params:
+      HUBS:
+        name: points.gml
+        type: vector
+      HUB_FIELD: id
+      HUB_FIELDS:
+      - id
+      - id2
+      SPOKES:
+        name: custom/spoke_points.gml
+        type: vector
+      SPOKE_FIELD: id
+      SPOKE_FIELDS:
+      - name
+    results:
+      OUTPUT:
+        name: expected/hub_lines_field_subset.gml
+        type: vector
+
   - algorithm: qgis:pointstopath
     name: Points to path (non grouped)
     params:

src/core/processing/qgsnativealgorithms.cpp

@@ -2885,11 +2885,22 @@ void QgsJoinWithLinesAlgorithm::initAlgorithm( const QVariantMap & )
                 QObject::tr( "Hub layer" ) ) );
   addParameter( new QgsProcessingParameterField( QStringLiteral( "HUB_FIELD" ),
                 QObject::tr( "Hub ID field" ), QVariant(), QStringLiteral( "HUBS" ) ) );
+
+  addParameter( new QgsProcessingParameterField( QStringLiteral( "HUB_FIELDS" ),
+                QObject::tr( "Hub layer fields to copy (leave empty to copy all fields)" ),
+                QVariant(), QStringLiteral( "HUBS" ), QgsProcessingParameterField::Any,
+                true, true ) );
+
   addParameter( new QgsProcessingParameterFeatureSource( QStringLiteral( "SPOKES" ),
                 QObject::tr( "Spoke layer" ) ) );
   addParameter( new QgsProcessingParameterField( QStringLiteral( "SPOKE_FIELD" ),
                 QObject::tr( "Spoke ID field" ), QVariant(), QStringLiteral( "SPOKES" ) ) );
 
+  addParameter( new QgsProcessingParameterField( QStringLiteral( "SPOKE_FIELDS" ),
+                QObject::tr( "Spoke layer fields to copy (leave empty to copy all fields)" ),
+                QVariant(), QStringLiteral( "SPOKES" ), QgsProcessingParameterField::Any,
+                true, true ) );
+
   addParameter( new QgsProcessingParameterFeatureSink( QStringLiteral( "OUTPUT" ), QObject::tr( "Hub lines" ), QgsProcessing::TypeVectorLine ) );
 }
 
@@ -2917,13 +2928,69 @@ QVariantMap QgsJoinWithLinesAlgorithm::processAlgorithm( const QVariantMap &para
 
   QString fieldHubName = parameterAsString( parameters, QStringLiteral( "HUB_FIELD" ), context );
   int fieldHubIndex = hubSource->fields().lookupField( fieldHubName );
+  const QStringList hubFieldsToCopy = parameterAsFields( parameters, QStringLiteral( "HUB_FIELDS" ), context );
+
   QString fieldSpokeName = parameterAsString( parameters, QStringLiteral( "SPOKE_FIELD" ), context );
   int fieldSpokeIndex = spokeSource->fields().lookupField( fieldSpokeName );
+  const QStringList spokeFieldsToCopy = parameterAsFields( parameters, QStringLiteral( "SPOKE_FIELDS" ), context );
 
   if ( fieldHubIndex < 0 || fieldSpokeIndex < 0 )
     throw QgsProcessingException( QObject::tr( "Invalid ID field" ) );
 
-  QgsFields fields = QgsProcessingUtils::combineFields( hubSource->fields(), spokeSource->fields() );
+  QgsFields hubOutFields;
+  QgsAttributeList hubFieldIndices;
+  if ( hubFieldsToCopy.empty() )
+  {
+    hubOutFields = hubSource->fields();
+    for ( int i = 0; i < hubOutFields.count(); ++i )
+    {
+      hubFieldIndices << i;
+    }
+  }
+  else
+  {
+    for ( const QString &field : hubFieldsToCopy )
+    {
+      int index = hubSource->fields().lookupField( field );
+      if ( index >= 0 )
+      {
+        hubFieldIndices << index;
+        hubOutFields.append( hubSource->fields().at( index ) );
+      }
+    }
+  }
+
+  QgsAttributeList hubFields2Fetch = hubFieldIndices;
+  hubFields2Fetch << fieldHubIndex;
+
+  QgsFields spokeOutFields;
+  QgsAttributeList spokeFieldIndices;
+  if ( spokeFieldsToCopy.empty() )
+  {
+    spokeOutFields = spokeSource->fields();
+    for ( int i = 0; i < spokeOutFields.count(); ++i )
+    {
+      spokeFieldIndices << i;
+    }
+  }
+  else
+  {
+    for ( const QString &field : spokeFieldsToCopy )
+    {
+      int index = spokeSource->fields().lookupField( field );
+      if ( index >= 0 )
+      {
+        spokeFieldIndices << index;
+        spokeOutFields.append( spokeSource->fields().at( index ) );
+      }
+    }
+  }
+
+  QgsAttributeList spokeFields2Fetch = spokeFieldIndices;
+  spokeFields2Fetch << fieldSpokeIndex;
+
+
+  QgsFields fields = QgsProcessingUtils::combineFields( hubOutFields, spokeOutFields );
 
   QgsWkbTypes::Type outType = QgsWkbTypes::LineString;
   bool hasZ = false;
@@ -2959,7 +3026,7 @@ QVariantMap QgsJoinWithLinesAlgorithm::processAlgorithm( const QVariantMap &para
     return p;
   };
 
-  QgsFeatureIterator hubFeatures = hubSource->getFeatures();
+  QgsFeatureIterator hubFeatures = hubSource->getFeatures( QgsFeatureRequest().setSubsetOfAttributes( hubFields2Fetch ) );
   double step = hubSource->featureCount() > 0 ? 100.0 / hubSource->featureCount() : 1;
   int i = 0;
   QgsFeature hubFeature;
@@ -2977,9 +3044,18 @@ QVariantMap QgsJoinWithLinesAlgorithm::processAlgorithm( const QVariantMap &para
       continue;
 
     QgsPoint hubPoint = getPointFromFeature( hubFeature );
-    QgsAttributes hubAttributes = hubFeature.attributes();
+
+    // only keep selected attributes
+    QgsAttributes hubAttributes;
+    for ( int j = 0; j < hubFeature.attributes().count(); ++j )
+    {
+      if ( !hubFieldIndices.contains( j ) )
+        continue;
+      hubAttributes << hubFeature.attribute( j );
+    }
 
     QgsFeatureRequest spokeRequest = QgsFeatureRequest().setDestinationCrs( hubSource->sourceCrs() );
+    spokeRequest.setSubsetOfAttributes( spokeFields2Fetch );
     spokeRequest.setFilterExpression( QgsExpression::createFieldEqualityExpression( fieldSpokeName, hubFeature.attribute( fieldHubIndex ) ) );
 
     QgsFeatureIterator spokeFeatures = spokeSource->getFeatures( spokeRequest );
@@ -2990,13 +3066,25 @@ QVariantMap QgsJoinWithLinesAlgorithm::processAlgorithm( const QVariantMap &para
       {
         break;
       }
+      if ( !spokeFeature.hasGeometry() )
+        continue;
 
       QgsPoint spokePoint = getPointFromFeature( spokeFeature );
       QgsGeometry line( new QgsLineString( QVector< QgsPoint >() << hubPoint << spokePoint ) );
 
       QgsFeature outFeature;
       QgsAttributes outAttributes = hubAttributes;
-      outAttributes.append( spokeFeature.attributes() );
+
+      // only keep selected attributes
+      QgsAttributes spokeAttributes;
+      for ( int j = 0; j < spokeFeature.attributes().count(); ++j )
+      {
+        if ( !spokeFieldIndices.contains( j ) )
+          continue;
+        spokeAttributes << spokeFeature.attribute( j );
+      }
+
+      outAttributes.append( spokeAttributes );
       outFeature.setAttributes( outAttributes );
       outFeature.setGeometry( line );
       sink->addFeature( outFeature, QgsFeatureSink::FastInsert );