Add method to format processing output values as strings

python/PyQt6/core/auto_generated/processing/qgsprocessingoutputs.sip.in

@@ -10,6 +10,8 @@
 
 
 
+
+
 class QgsProcessingOutputDefinition
 {
 %Docstring(signature="appended")
@@ -121,6 +123,19 @@ Returns ``True`` if the output was automatically created when adding a parameter
 .. seealso:: :py:func:`setAutoCreated`
 
 .. versionadded:: 3.14
+%End
+
+    virtual QString valueAsString( const QVariant &value, QgsProcessingContext &context, bool &ok /Out/ ) const;
+%Docstring
+Returns a string version of the parameter output ``value`` (if possible).
+
+:param value: value to convert
+:param context: processing context
+
+:return: - value converted to string
+         - ok: will be set to ``True`` if value could be represented as a string.
+
+.. versionadded:: 3.36
 %End
 
   protected:
@@ -159,6 +174,7 @@ Returns the type name for the output class.
 
     virtual QString type() const;
 
+
 };
 
 class QgsProcessingOutputVectorLayer : QgsProcessingOutputDefinition
@@ -284,6 +300,9 @@ Returns the type name for the output class.
 %End
     virtual QString type() const;
 
+    virtual QString valueAsString( const QVariant &value, QgsProcessingContext &context, bool &ok /Out/ ) const;
+
+
 };
 
 class QgsProcessingOutputHtml : QgsProcessingOutputDefinition
@@ -336,6 +355,9 @@ Returns the type name for the output class.
 %End
     virtual QString type() const;
 
+    virtual QString valueAsString( const QVariant &value, QgsProcessingContext &context, bool &ok /Out/ ) const;
+
+
 };
 
 class QgsProcessingOutputNumber : QgsProcessingOutputDefinition
@@ -361,6 +383,9 @@ Constructor for QgsProcessingOutputNumber.
 Returns the type name for the output class.
 %End
     virtual QString type() const;
+    virtual QString valueAsString( const QVariant &value, QgsProcessingContext &context, bool &ok /Out/ ) const;
+
+
 };
 
 class QgsProcessingOutputString : QgsProcessingOutputDefinition
@@ -411,6 +436,8 @@ Constructor for :py:class:`QgsProcessingOutputNumber`.
 Returns the type name for the output class.
 %End
     virtual QString type() const;
+    virtual QString valueAsString( const QVariant &value, QgsProcessingContext &context, bool &ok /Out/ ) const;
+
 };
 
 class QgsProcessingOutputFolder : QgsProcessingOutputDefinition

python/core/auto_generated/processing/qgsprocessingoutputs.sip.in

@@ -10,6 +10,8 @@
 
 
 
+
+
 class QgsProcessingOutputDefinition
 {
 %Docstring(signature="appended")
@@ -121,6 +123,19 @@ Returns ``True`` if the output was automatically created when adding a parameter
 .. seealso:: :py:func:`setAutoCreated`
 
 .. versionadded:: 3.14
+%End
+
+    virtual QString valueAsString( const QVariant &value, QgsProcessingContext &context, bool &ok /Out/ ) const;
+%Docstring
+Returns a string version of the parameter output ``value`` (if possible).
+
+:param value: value to convert
+:param context: processing context
+
+:return: - value converted to string
+         - ok: will be set to ``True`` if value could be represented as a string.
+
+.. versionadded:: 3.36
 %End
 
   protected:
@@ -159,6 +174,7 @@ Returns the type name for the output class.
 
     virtual QString type() const;
 
+
 };
 
 class QgsProcessingOutputVectorLayer : QgsProcessingOutputDefinition
@@ -284,6 +300,9 @@ Returns the type name for the output class.
 %End
     virtual QString type() const;
 
+    virtual QString valueAsString( const QVariant &value, QgsProcessingContext &context, bool &ok /Out/ ) const;
+
+
 };
 
 class QgsProcessingOutputHtml : QgsProcessingOutputDefinition
@@ -336,6 +355,9 @@ Returns the type name for the output class.
 %End
     virtual QString type() const;
 
+    virtual QString valueAsString( const QVariant &value, QgsProcessingContext &context, bool &ok /Out/ ) const;
+
+
 };
 
 class QgsProcessingOutputNumber : QgsProcessingOutputDefinition
@@ -361,6 +383,9 @@ Constructor for QgsProcessingOutputNumber.
 Returns the type name for the output class.
 %End
     virtual QString type() const;
+    virtual QString valueAsString( const QVariant &value, QgsProcessingContext &context, bool &ok /Out/ ) const;
+
+
 };
 
 class QgsProcessingOutputString : QgsProcessingOutputDefinition
@@ -411,6 +436,8 @@ Constructor for :py:class:`QgsProcessingOutputNumber`.
 Returns the type name for the output class.
 %End
     virtual QString type() const;
+    virtual QString valueAsString( const QVariant &value, QgsProcessingContext &context, bool &ok /Out/ ) const;
+
 };
 
 class QgsProcessingOutputFolder : QgsProcessingOutputDefinition

src/core/processing/qgsprocessingoutputs.cpp

@@ -16,12 +16,30 @@
  ***************************************************************************/
 
 #include "qgsprocessingoutputs.h"
+#include "qgsvariantutils.h"
 
 QgsProcessingOutputDefinition::QgsProcessingOutputDefinition( const QString &name, const QString &description )
   : mName( name )
   , mDescription( description )
 {}
 
+QString QgsProcessingOutputDefinition::valueAsString( const QVariant &value, QgsProcessingContext &, bool &ok ) const
+{
+  if ( QgsVariantUtils::isNull( value ) )
+  {
+    ok = true;
+    return QObject::tr( "NULL" );
+  }
+
+  if ( value.type() == QVariant::String )
+  {
+    ok = true;
+    return value.toString();
+  }
+  ok = false;
+  return QString();
+}
+
 QgsProcessingOutputVectorLayer::QgsProcessingOutputVectorLayer( const QString &name, const QString &description, QgsProcessing::SourceType type )
   : QgsProcessingOutputDefinition( name, description )
   , mDataType( type )
@@ -57,6 +75,24 @@ QgsProcessingOutputNumber::QgsProcessingOutputNumber( const QString &name, const
   : QgsProcessingOutputDefinition( name, description )
 {}
 
+QString QgsProcessingOutputNumber::valueAsString( const QVariant &value, QgsProcessingContext &context, bool &ok ) const
+{
+  ok = false;
+  switch ( value.type() )
+  {
+    case QVariant::Int:
+    case QVariant::UInt:
+    case QVariant::LongLong:
+    case QVariant::ULongLong:
+    case QVariant::Double:
+      ok = true;
+      return value.toString();
+    default:
+      break;
+  }
+  return QgsProcessingOutputDefinition::valueAsString( value, context, ok );
+}
+
 QgsProcessingOutputString::QgsProcessingOutputString( const QString &name, const QString &description )
   : QgsProcessingOutputDefinition( name, description )
 {}
@@ -65,6 +101,17 @@ QgsProcessingOutputBoolean::QgsProcessingOutputBoolean( const QString &name, con
   : QgsProcessingOutputDefinition( name, description )
 {}
 
+QString QgsProcessingOutputBoolean::valueAsString( const QVariant &value, QgsProcessingContext &context, bool &ok ) const
+{
+  ok = false;
+  if ( value.type() == QVariant::Bool )
+  {
+    ok = true;
+    return value.toBool() ? QObject::tr( "True" ) : QObject::tr( "False" );
+  }
+  return QgsProcessingOutputDefinition::valueAsString( value, context, ok );
+}
+
 QgsProcessingOutputFolder::QgsProcessingOutputFolder( const QString &name, const QString &description )
   : QgsProcessingOutputDefinition( name, description )
 {}
@@ -91,6 +138,37 @@ QString QgsProcessingOutputMultipleLayers::type() const
   return typeName();
 }
 
+QString QgsProcessingOutputMultipleLayers::valueAsString( const QVariant &value, QgsProcessingContext &context, bool &ok ) const
+{
+  ok = false;
+  switch ( value.type() )
+  {
+    case QVariant::List:
+    {
+      ok = true;
+      const QVariantList list = value.toList();
+
+      QStringList layerNames;
+      for ( const QVariant &v : list )
+      {
+        layerNames << v.toString();
+      }
+      return layerNames.join( QStringLiteral( ", " ) );
+    }
+
+    case QVariant::StringList:
+    {
+      ok = true;
+      const QStringList list = value.toStringList();
+      return list.join( QStringLiteral( ", " ) );
+    }
+
+    default:
+      break;
+  }
+  return QgsProcessingOutputDefinition::valueAsString( value, context, ok );
+}
+
 QgsProcessingOutputConditionalBranch::QgsProcessingOutputConditionalBranch( const QString &name, const QString &description )
   : QgsProcessingOutputDefinition( name, description )
 {}
@@ -105,3 +183,45 @@ QString QgsProcessingOutputVariant::type() const
 {
   return typeName();
 }
+
+QString QgsProcessingOutputVariant::valueAsString( const QVariant &value, QgsProcessingContext &context, bool &ok ) const
+{
+  ok = false;
+  switch ( value.type() )
+  {
+    case QVariant::Int:
+    case QVariant::UInt:
+    case QVariant::LongLong:
+    case QVariant::ULongLong:
+    case QVariant::Double:
+      ok = true;
+      return value.toString();
+    case QVariant::Bool:
+      ok = true;
+      return value.toBool() ? QObject::tr( "True" ) : QObject::tr( "False" );
+
+    case QVariant::List:
+    {
+      ok = true;
+      const QVariantList list = value.toList();
+
+      QStringList names;
+      for ( const QVariant &v : list )
+      {
+        names << v.toString();
+      }
+      return names.join( QStringLiteral( ", " ) );
+    }
+
+    case QVariant::StringList:
+    {
+      ok = true;
+      const QStringList list = value.toStringList();
+      return list.join( QStringLiteral( ", " ) );
+    }
+
+    default:
+      break;
+  }
+  return QgsProcessingOutputDefinition::valueAsString( value, context, ok );
+}

src/core/processing/qgsprocessingoutputs.h

@@ -21,6 +21,9 @@
 #include "qgis_core.h"
 #include "qgis.h"
 #include "qgsprocessing.h"
+
+class QgsProcessingContext;
+
 //
 // Output definitions
 //
@@ -132,6 +135,18 @@ class CORE_EXPORT QgsProcessingOutputDefinition
      */
     bool autoCreated() const { return mAutoCreated; }
 
+    /**
+     * Returns a string version of the parameter output \a value (if possible).
+     *
+     * \param value value to convert
+     * \param context processing context
+     * \param ok will be set to TRUE if value could be represented as a string.
+     * \returns value converted to string
+     *
+     * \since QGIS 3.36
+     */
+    virtual QString valueAsString( const QVariant &value, QgsProcessingContext &context, bool &ok SIP_OUT ) const;
+
   protected:
 
     //! Output name
@@ -171,6 +186,7 @@ class CORE_EXPORT QgsProcessingOutputMapLayer : public QgsProcessingOutputDefini
     static QString typeName() { return QStringLiteral( "outputLayer" ); }
 
     QString type() const override;
+
 };
 
 /**
@@ -282,6 +298,8 @@ class CORE_EXPORT QgsProcessingOutputMultipleLayers : public QgsProcessingOutput
      */
     static QString typeName() { return QStringLiteral( "outputMultilayer" ); }
     QString type() const override;
+    QString valueAsString( const QVariant &value, QgsProcessingContext &context, bool &ok SIP_OUT ) const override;
+
 };
 
 /**
@@ -327,6 +345,8 @@ class CORE_EXPORT QgsProcessingOutputVariant : public QgsProcessingOutputDefinit
      */
     static QString typeName() { return QStringLiteral( "outputVariant" ); }
     QString type() const override;
+    QString valueAsString( const QVariant &value, QgsProcessingContext &context, bool &ok SIP_OUT ) const override;
+
 };
 
 /**
@@ -349,6 +369,8 @@ class CORE_EXPORT QgsProcessingOutputNumber : public QgsProcessingOutputDefiniti
      */
     static QString typeName() { return QStringLiteral( "outputNumber" ); }
     QString type() const override { return typeName(); }
+    QString valueAsString( const QVariant &value, QgsProcessingContext &context, bool &ok SIP_OUT ) const override;
+
 };
 
 /**
@@ -393,6 +415,7 @@ class CORE_EXPORT QgsProcessingOutputBoolean : public QgsProcessingOutputDefinit
      */
     static QString typeName() { return QStringLiteral( "outputBoolean" ); }
     QString type() const override { return typeName(); }
+    QString valueAsString( const QVariant &value, QgsProcessingContext &context, bool &ok SIP_OUT ) const override;
 };
 
 /**

tests/src/analysis/testqgsprocessing.cpp

@@ -818,6 +818,7 @@ class TestQgsProcessing: public QgsTest
     void formatHelp();
     void preprocessParameters();
     void guiDefaultParameterValues();
+    void testOutputs();
 
   private:
 
@@ -12782,5 +12783,195 @@ void TestQgsProcessing::guiDefaultParameterValues()
   s.remove( QStringLiteral( "/Processing/DefaultGuiParam/testAlgorithm/testStringParameter" ) );
 }
 
+void TestQgsProcessing::testOutputs()
+{
+  QgsProcessingContext context;
+  bool ok = false;
+  QgsProcessingOutputVectorLayer outputVectorLayer( QStringLiteral( "vl" ) );
+  QCOMPARE( outputVectorLayer.valueAsString( QStringLiteral( "/home/test/test.shp" ), context, ok ),
+            QStringLiteral( "/home/test/test.shp" ) );
+  QVERIFY( ok );
+  ok = false;
+  QCOMPARE( outputVectorLayer.valueAsString( QVariant(), context, ok ),
+            QStringLiteral( "NULL" ) );
+  QVERIFY( ok );
+  ok = false;
+
+  QgsProcessingOutputRasterLayer outputRasterLayer( QStringLiteral( "rl" ) );
+  QCOMPARE( outputRasterLayer.valueAsString( QStringLiteral( "/home/test/test.tiff" ), context, ok ),
+            QStringLiteral( "/home/test/test.tiff" ) );
+  QVERIFY( ok );
+  ok = false;
+  QCOMPARE( outputRasterLayer.valueAsString( QVariant(), context, ok ),
+            QStringLiteral( "NULL" ) );
+  QVERIFY( ok );
+  ok = false;
+
+  QgsProcessingOutputPointCloudLayer outputPointCloudLayer( QStringLiteral( "pcl" ) );
+  QCOMPARE( outputPointCloudLayer.valueAsString( QStringLiteral( "/home/test/test.laz" ), context, ok ),
+            QStringLiteral( "/home/test/test.laz" ) );
+  QVERIFY( ok );
+  ok = false;
+  QCOMPARE( outputPointCloudLayer.valueAsString( QVariant(), context, ok ),
+            QStringLiteral( "NULL" ) );
+  QVERIFY( ok );
+  ok = false;
+
+  QgsProcessingOutputVectorTileLayer outputVectorTileLayer( QStringLiteral( "vtl" ) );
+  QCOMPARE( outputVectorTileLayer.valueAsString( QStringLiteral( "/home/test/test.mbtiles" ), context, ok ),
+            QStringLiteral( "/home/test/test.mbtiles" ) );
+  QVERIFY( ok );
+  ok = false;
+  QCOMPARE( outputVectorTileLayer.valueAsString( QVariant(), context, ok ),
+            QStringLiteral( "NULL" ) );
+  QVERIFY( ok );
+  ok = false;
+
+  QgsProcessingOutputMapLayer outputMapLayer( QStringLiteral( "ml" ) );
+  QCOMPARE( outputMapLayer.valueAsString( QStringLiteral( "/home/test/test.mbtiles" ), context, ok ),
+            QStringLiteral( "/home/test/test.mbtiles" ) );
+  QVERIFY( ok );
+  ok = false;
+  QCOMPARE( outputMapLayer.valueAsString( QVariant(), context, ok ),
+            QStringLiteral( "NULL" ) );
+  QVERIFY( ok );
+  ok = false;
+
+  QgsProcessingOutputMultipleLayers outputMultipleLayers( QStringLiteral( "ml" ) );
+  QCOMPARE( outputMultipleLayers.valueAsString( QStringLiteral( "/home/test/test.mbtiles" ), context, ok ),
+            QStringLiteral( "/home/test/test.mbtiles" ) );
+  QVERIFY( ok );
+  ok = false;
+  QCOMPARE( outputMultipleLayers.valueAsString( QVariant(), context, ok ),
+            QStringLiteral( "NULL" ) );
+  QVERIFY( ok );
+  QCOMPARE( outputMultipleLayers.valueAsString( QStringList() << QStringLiteral( "/home/test/test.mbtiles" )
+            << QStringLiteral( "/home/test/test.shp" )
+            << QStringLiteral( "/home/test/test.tif" ), context, ok ),
+            QStringLiteral( "/home/test/test.mbtiles, /home/test/test.shp, /home/test/test.tif" ) );
+  QVERIFY( ok );
+  ok = false;
+  QCOMPARE( outputMultipleLayers.valueAsString( QVariantList() << QStringLiteral( "/home/test/test.mbtiles" )
+            << QStringLiteral( "/home/test/test.shp" )
+            << QStringLiteral( "/home/test/test.tif" ), context, ok ),
+            QStringLiteral( "/home/test/test.mbtiles, /home/test/test.shp, /home/test/test.tif" ) );
+  QVERIFY( ok );
+  ok = false;
+
+  QgsProcessingOutputHtml outputHtml( QStringLiteral( "html" ) );
+  QCOMPARE( outputHtml.valueAsString( QStringLiteral( "/home/test/test.html" ), context, ok ),
+            QStringLiteral( "/home/test/test.html" ) );
+  QVERIFY( ok );
+  ok = false;
+  QCOMPARE( outputHtml.valueAsString( QVariant(), context, ok ),
+            QStringLiteral( "NULL" ) );
+  QVERIFY( ok );
+  ok = false;
+
+  QgsProcessingOutputFile outputFile( QStringLiteral( "file" ) );
+  QCOMPARE( outputFile.valueAsString( QStringLiteral( "/home/test/test.txt" ), context, ok ),
+            QStringLiteral( "/home/test/test.txt" ) );
+  QVERIFY( ok );
+  ok = false;
+  QCOMPARE( outputFile.valueAsString( QVariant(), context, ok ),
+            QStringLiteral( "NULL" ) );
+  QVERIFY( ok );
+  ok = false;
+
+  QgsProcessingOutputFolder outputFolder( QStringLiteral( "folder" ) );
+  QCOMPARE( outputFolder.valueAsString( QStringLiteral( "/home/test" ), context, ok ),
+            QStringLiteral( "/home/test" ) );
+  QVERIFY( ok );
+  ok = false;
+  QCOMPARE( outputFolder.valueAsString( QVariant(), context, ok ),
+            QStringLiteral( "NULL" ) );
+  QVERIFY( ok );
+  ok = false;
+
+  QgsProcessingOutputNumber outputNumber( QStringLiteral( "number" ) );
+  QCOMPARE( outputNumber.valueAsString( QStringLiteral( "xxx" ), context, ok ),
+            QStringLiteral( "xxx" ) );
+  QVERIFY( ok );
+  ok = false;
+  QCOMPARE( outputNumber.valueAsString( 5, context, ok ),
+            QStringLiteral( "5" ) );
+  QVERIFY( ok );
+  ok = false;
+  QCOMPARE( outputNumber.valueAsString( 5.5, context, ok ),
+            QStringLiteral( "5.5" ) );
+  QVERIFY( ok );
+  ok = false;
+  QCOMPARE( outputNumber.valueAsString( QVariant(), context, ok ),
+            QStringLiteral( "NULL" ) );
+  QVERIFY( ok );
+  ok = false;
+
+  QgsProcessingOutputString outputString( QStringLiteral( "string" ) );
+  QCOMPARE( outputString.valueAsString( QStringLiteral( "lalala" ), context, ok ),
+            QStringLiteral( "lalala" ) );
+  QVERIFY( ok );
+  ok = false;
+  QCOMPARE( outputString.valueAsString( QVariant(), context, ok ),
+            QStringLiteral( "NULL" ) );
+  QVERIFY( ok );
+  ok = false;
+
+  QgsProcessingOutputBoolean outputBoolean( QStringLiteral( "string" ) );
+  QCOMPARE( outputBoolean.valueAsString( QStringLiteral( "lalala" ), context, ok ),
+            QStringLiteral( "lalala" ) );
+  QVERIFY( ok );
+  ok = false;
+  QCOMPARE( outputBoolean.valueAsString( QVariant(), context, ok ),
+            QStringLiteral( "NULL" ) );
+  QVERIFY( ok );
+  ok = false;
+  QCOMPARE( outputBoolean.valueAsString( QVariant( true ), context, ok ),
+            QStringLiteral( "True" ) );
+  QVERIFY( ok );
+  ok = false;
+  QCOMPARE( outputBoolean.valueAsString( QVariant( false ), context, ok ),
+            QStringLiteral( "False" ) );
+  QVERIFY( ok );
+  ok = false;
+
+  QgsProcessingOutputVariant outputVariant( QStringLiteral( "variant" ) );
+  QCOMPARE( outputVariant.valueAsString( QStringLiteral( "lalala" ), context, ok ),
+            QStringLiteral( "lalala" ) );
+  QVERIFY( ok );
+  ok = false;
+  QCOMPARE( outputVariant.valueAsString( QVariant(), context, ok ),
+            QStringLiteral( "NULL" ) );
+  QVERIFY( ok );
+  ok = false;
+  QCOMPARE( outputVariant.valueAsString( QVariant( true ), context, ok ),
+            QStringLiteral( "True" ) );
+  QVERIFY( ok );
+  ok = false;
+  QCOMPARE( outputVariant.valueAsString( QVariant( false ), context, ok ),
+            QStringLiteral( "False" ) );
+  QVERIFY( ok );
+  ok = false;
+  QCOMPARE( outputVariant.valueAsString( 5, context, ok ),
+            QStringLiteral( "5" ) );
+  QVERIFY( ok );
+  ok = false;
+  QCOMPARE( outputVariant.valueAsString( 5.5, context, ok ),
+            QStringLiteral( "5.5" ) );
+  QVERIFY( ok );
+  ok = false;
+  QCOMPARE( outputVariant.valueAsString( QStringList() << QStringLiteral( "/home/test/test.mbtiles" )
+                                         << QStringLiteral( "/home/test/test.shp" )
+                                         << QStringLiteral( "/home/test/test.tif" ), context, ok ),
+            QStringLiteral( "/home/test/test.mbtiles, /home/test/test.shp, /home/test/test.tif" ) );
+  QVERIFY( ok );
+  ok = false;
+  QCOMPARE( outputVariant.valueAsString( QVariantList() << QStringLiteral( "/home/test/test.mbtiles" )
+                                         << QStringLiteral( "/home/test/test.shp" )
+                                         << QStringLiteral( "/home/test/test.tif" ), context, ok ),
+            QStringLiteral( "/home/test/test.mbtiles, /home/test/test.shp, /home/test/test.tif" ) );
+  QVERIFY( ok );
+  ok = false;
+}
+
 QGSTEST_MAIN( TestQgsProcessing )
 #include "testqgsprocessing.moc"