Add Processing algorithms to deal with metadata

src/analysis/CMakeLists.txt

@@ -259,6 +259,7 @@ set(QGIS_ANALYSIS_SRCS
   processing/qgsalgorithmzonalstatistics.cpp
   processing/qgsalgorithmzonalstatisticsfeaturebased.cpp
   processing/qgsbookmarkalgorithms.cpp
+  processing/qgsmetadataalgorithms.cpp
   processing/qgsprojectstylealgorithms.cpp
   processing/qgsstylealgorithms.cpp
 

src/analysis/processing/qgsmetadataalgorithms.cpp

@@ -0,0 +1,251 @@
+/***************************************************************************
+                         qgsmetadataalgorithms.cpp
+                         ---------------------
+    begin                : November 2024
+    copyright            : (C) 2024 by Alexander Bruy
+    email                : alexander dot bruy at gmail dot com
+ ***************************************************************************/
+
+/***************************************************************************
+ *                                                                         *
+ *   This program is free software; you can redistribute it and/or modify  *
+ *   it under the terms of the GNU General Public License as published by  *
+ *   the Free Software Foundation; either version 2 of the License, or     *
+ *   (at your option) any later version.                                   *
+ *                                                                         *
+ ***************************************************************************/
+
+#include "qgsmetadataalgorithms.h"
+
+///@cond PRIVATE
+
+QString QgsCopyLayerMetadataAlgorithm::name() const
+{
+  return QStringLiteral( "copylayermetadata" );
+}
+
+QString QgsCopyLayerMetadataAlgorithm::displayName() const
+{
+  return QObject::tr( "Copy layer metadata" );
+}
+
+QStringList QgsCopyLayerMetadataAlgorithm::tags() const
+{
+  return QObject::tr( "change,layer,metadata,qmd" ).split( ',' );
+}
+
+QString QgsCopyLayerMetadataAlgorithm::group() const
+{
+  return QObject::tr( "Metadata tools" );
+}
+
+QString QgsCopyLayerMetadataAlgorithm::groupId() const
+{
+  return QStringLiteral( "metadatatools" );
+}
+
+QString QgsCopyLayerMetadataAlgorithm::shortHelpString() const
+{
+  return QObject::tr( "Copies metadata from an input layer to a target layer.\n\nAny existing metadata in the target layer will be replaced." );
+}
+
+QgsCopyLayerMetadataAlgorithm *QgsCopyLayerMetadataAlgorithm::createInstance() const
+{
+  return new QgsCopyLayerMetadataAlgorithm();
+}
+
+void QgsCopyLayerMetadataAlgorithm::initAlgorithm( const QVariantMap & )
+{
+  addParameter( new QgsProcessingParameterMapLayer( QStringLiteral( "INPUT" ), QObject::tr( "Source layer" ) ) );
+  addParameter( new QgsProcessingParameterMapLayer( QStringLiteral( "TARGET" ), QObject::tr( "Target layer" ) ) );
+  addParameter( new QgsProcessingParameterBoolean( QStringLiteral( "DEFAULT" ), QObject::tr( "Save metadata as default" ), false ) );
+  addOutput( new QgsProcessingOutputMapLayer( QStringLiteral( "OUTPUT" ), QObject::tr( "Updated layer" ) ) );
+}
+
+bool QgsCopyLayerMetadataAlgorithm::prepareAlgorithm( const QVariantMap &parameters, QgsProcessingContext &context, QgsProcessingFeedback * )
+{
+  QgsMapLayer *inputLayer = parameterAsLayer( parameters, QStringLiteral( "INPUT" ), context );
+  QgsMapLayer *targetLayer = parameterAsLayer( parameters, QStringLiteral( "TARGET" ), context );
+  const bool saveAsDefault = parameterAsBool( parameters, QStringLiteral( "DEFAULT" ), context );
+
+  if ( !inputLayer )
+    throw QgsProcessingException( QObject::tr( "Invalid input layer" ) );
+
+  if ( !targetLayer )
+    throw QgsProcessingException( QObject::tr( "Invalid target layer" ) );
+
+  mLayerId = targetLayer->id();
+
+  targetLayer->setMetadata( *inputLayer->metadata() );
+  if ( saveAsDefault )
+  {
+    bool ok;
+    targetLayer->saveDefaultMetadata( ok );
+    if ( !ok )
+    {
+      throw QgsProcessingException( QObject::tr( "Failed to save metadata as default metadata." ) );
+    }
+  }
+  return true;
+}
+
+QVariantMap QgsCopyLayerMetadataAlgorithm::processAlgorithm( const QVariantMap &parameters, QgsProcessingContext &context, QgsProcessingFeedback * )
+{
+  Q_UNUSED( parameters );
+  Q_UNUSED( context );
+
+  QVariantMap results;
+  results.insert( QStringLiteral( "OUTPUT" ), mLayerId );
+  return results;
+}
+
+///
+
+QString QgsApplyLayerMetadataAlgorithm::name() const
+{
+  return QStringLiteral( "setlayermetadata" );
+}
+
+QString QgsApplyLayerMetadataAlgorithm::displayName() const
+{
+  return QObject::tr( "Set layer metadata" );
+}
+
+QStringList QgsApplyLayerMetadataAlgorithm::tags() const
+{
+  return QObject::tr( "change,layer,metadata,qmd" ).split( ',' );
+}
+
+QString QgsApplyLayerMetadataAlgorithm::group() const
+{
+  return QObject::tr( "Metadata tools" );
+}
+
+QString QgsApplyLayerMetadataAlgorithm::groupId() const
+{
+  return QStringLiteral( "metadatatools" );
+}
+
+QString QgsApplyLayerMetadataAlgorithm::shortHelpString() const
+{
+  return QObject::tr( "Applies the metadata to a layer. The metadata must be defined as QMD file.\n\nAny existing metadata in the layer will be replaced." );
+}
+
+QgsApplyLayerMetadataAlgorithm *QgsApplyLayerMetadataAlgorithm::createInstance() const
+{
+  return new QgsApplyLayerMetadataAlgorithm();
+}
+
+void QgsApplyLayerMetadataAlgorithm::initAlgorithm( const QVariantMap & )
+{
+  addParameter( new QgsProcessingParameterMapLayer( QStringLiteral( "INPUT" ), QObject::tr( "Layer" ) ) );
+  addParameter( new QgsProcessingParameterFile( QStringLiteral( "METADATA" ), QObject::tr( "Metadata file" ), Qgis::ProcessingFileParameterBehavior::File, QStringLiteral( "qmd" ) ) );
+  addParameter( new QgsProcessingParameterBoolean( QStringLiteral( "DEFAULT" ), QObject::tr( "Save metadata as default" ), false ) );
+  addOutput( new QgsProcessingOutputMapLayer( QStringLiteral( "OUTPUT" ), QObject::tr( "Updated" ) ) );
+}
+
+bool QgsApplyLayerMetadataAlgorithm::prepareAlgorithm( const QVariantMap &parameters, QgsProcessingContext &context, QgsProcessingFeedback * )
+{
+  QgsMapLayer *layer = parameterAsLayer( parameters, QStringLiteral( "INPUT" ), context );
+  const QString metadata = parameterAsFile( parameters, QStringLiteral( "METADATA" ), context );
+  const bool saveAsDefault = parameterAsBool( parameters, QStringLiteral( "DEFAULT" ), context );
+
+  if ( !layer )
+    throw QgsProcessingException( QObject::tr( "Invalid input layer" ) );
+
+  mLayerId = layer->id();
+
+  bool ok = false;
+  const QString msg = layer->loadNamedMetadata( metadata, ok );
+  if ( !ok )
+  {
+    throw QgsProcessingException( QObject::tr( "Failed to apply metadata. Error: %1" ).arg( msg ) );
+  }
+
+  if ( saveAsDefault )
+  {
+    bool ok;
+    layer->saveDefaultMetadata( ok );
+    if ( !ok )
+    {
+      throw QgsProcessingException( QObject::tr( "Failed to save metadata as default metadata." ) );
+    }
+  }
+
+  return true;
+}
+
+QVariantMap QgsApplyLayerMetadataAlgorithm::processAlgorithm( const QVariantMap &parameters, QgsProcessingContext &context, QgsProcessingFeedback * )
+{
+  Q_UNUSED( parameters );
+  Q_UNUSED( context );
+
+  QVariantMap results;
+  results.insert( QStringLiteral( "OUTPUT" ), mLayerId );
+  return results;
+}
+
+///
+
+QString QgsExportLayerMetadataAlgorithm::name() const
+{
+  return QStringLiteral( "exportlayermetadata" );
+}
+
+QString QgsExportLayerMetadataAlgorithm::displayName() const
+{
+  return QObject::tr( "Export layer metadata" );
+}
+
+QStringList QgsExportLayerMetadataAlgorithm::tags() const
+{
+  return QObject::tr( "export,layer,metadata,qmd" ).split( ',' );
+}
+
+QString QgsExportLayerMetadataAlgorithm::group() const
+{
+  return QObject::tr( "Metadata tools" );
+}
+
+QString QgsExportLayerMetadataAlgorithm::groupId() const
+{
+  return QStringLiteral( "metadatatools" );
+}
+
+QString QgsExportLayerMetadataAlgorithm::shortHelpString() const
+{
+  return QObject::tr( "Exports layer's metadata to a QMD file." );
+}
+
+QgsExportLayerMetadataAlgorithm *QgsExportLayerMetadataAlgorithm::createInstance() const
+{
+  return new QgsExportLayerMetadataAlgorithm();
+}
+
+void QgsExportLayerMetadataAlgorithm::initAlgorithm( const QVariantMap & )
+{
+  addParameter( new QgsProcessingParameterMapLayer( QStringLiteral( "INPUT" ), QObject::tr( "Layer" ) ) );
+  addParameter( new QgsProcessingParameterFileDestination( QStringLiteral( "OUTPUT" ), QObject::tr( "Output" ), QObject::tr( "QGIS Metadata File" ) + QStringLiteral( " (*.qmd *.QMD)" ) ) );
+}
+
+QVariantMap QgsExportLayerMetadataAlgorithm::processAlgorithm( const QVariantMap &parameters, QgsProcessingContext &context, QgsProcessingFeedback * )
+{
+  QgsMapLayer *layer = parameterAsLayer( parameters, QStringLiteral( "INPUT" ), context );
+  const QString outputFile = parameterAsString( parameters, QStringLiteral( "OUTPUT" ), context );
+
+  if ( !layer )
+    throw QgsProcessingException( QObject::tr( "Invalid input layer" ) );
+
+  bool ok = false;
+  const QString message = layer->saveNamedMetadata( outputFile, ok );
+  if ( !ok )
+  {
+    throw QgsProcessingException( QObject::tr( "Failed to save metadata. Error: %1" ).arg( message ) );
+  }
+
+  QVariantMap results;
+  results.insert( QStringLiteral( "OUTPUT" ), outputFile );
+  return results;
+}
+
+///@endcond

src/analysis/processing/qgsmetadataalgorithms.h

@@ -0,0 +1,111 @@
+/***************************************************************************
+                         qgsmetadataalgorithms.h
+                         ---------------------
+    begin                : November 2024
+    copyright            : (C) 2024 by Alexander Bruy
+    email                : alexander dot bruy at gmail dot com
+ ***************************************************************************/
+
+/***************************************************************************
+ *                                                                         *
+ *   This program is free software; you can redistribute it and/or modify  *
+ *   it under the terms of the GNU General Public License as published by  *
+ *   the Free Software Foundation; either version 2 of the License, or     *
+ *   (at your option) any later version.                                   *
+ *                                                                         *
+ ***************************************************************************/
+
+#ifndef QGSMETADATAALGORITHMS_H
+#define QGSMETADATAALGORITHMS_H
+
+#define SIP_NO_FILE
+
+#include "qgis_sip.h"
+#include "qgsprocessingalgorithm.h"
+
+///@cond PRIVATE
+
+/**
+ * Native copy layer metadata algorithm.
+ */
+class QgsCopyLayerMetadataAlgorithm : public QgsProcessingAlgorithm
+{
+  public:
+    QgsCopyLayerMetadataAlgorithm() = default;
+    QString name() const override;
+    QString displayName() const override;
+    QStringList tags() const override;
+    QString group() const override;
+    QString groupId() const override;
+    QString shortHelpString() const override;
+    void initAlgorithm( const QVariantMap &configuration = QVariantMap() ) override;
+    QgsCopyLayerMetadataAlgorithm *createInstance() const override SIP_FACTORY;
+
+  protected:
+
+    bool prepareAlgorithm( const QVariantMap &parameters, QgsProcessingContext &context, QgsProcessingFeedback *feedback ) override;
+    QVariantMap processAlgorithm( const QVariantMap &parameters,
+                                  QgsProcessingContext &context, QgsProcessingFeedback * ) override;
+
+  private:
+
+    QString mLayerId;
+};
+
+/**
+ * Native apply layer metadata algorithm.
+ */
+class QgsApplyLayerMetadataAlgorithm : public QgsProcessingAlgorithm
+{
+  public:
+    QgsApplyLayerMetadataAlgorithm() = default;
+    QString name() const override;
+    QString displayName() const override;
+    QStringList tags() const override;
+    QString group() const override;
+    QString groupId() const override;
+    QString shortHelpString() const override;
+    void initAlgorithm( const QVariantMap &configuration = QVariantMap() ) override;
+    QgsApplyLayerMetadataAlgorithm *createInstance() const override SIP_FACTORY;
+
+  protected:
+
+    bool prepareAlgorithm( const QVariantMap &parameters, QgsProcessingContext &context, QgsProcessingFeedback *feedback ) override;
+    QVariantMap processAlgorithm( const QVariantMap &parameters,
+                                  QgsProcessingContext &context, QgsProcessingFeedback * ) override;
+
+  private:
+
+    QString mLayerId;
+};
+
+
+/**
+ * Native export layer metadata algorithm.
+ */
+class QgsExportLayerMetadataAlgorithm : public QgsProcessingAlgorithm
+{
+  public:
+    QgsExportLayerMetadataAlgorithm() = default;
+    QString name() const override;
+    QString displayName() const override;
+    QStringList tags() const override;
+    QString group() const override;
+    QString groupId() const override;
+    QString shortHelpString() const override;
+    void initAlgorithm( const QVariantMap &configuration = QVariantMap() ) override;
+    QgsExportLayerMetadataAlgorithm *createInstance() const override SIP_FACTORY;
+
+  protected:
+
+    QVariantMap processAlgorithm( const QVariantMap &parameters,
+                                  QgsProcessingContext &context, QgsProcessingFeedback * ) override;
+
+  private:
+
+    QString mLayerId;
+};
+
+///@endcond PRIVATE
+
+#endif // QGSMETADATAALGORITHMS_H