[processing] Add API to allow custom expression variables to be set

for a model
qgis · Feb 22, 2019 · e31fb92 · e31fb92
1 parent fbc22e2
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diff --git a/python/core/auto_generated/processing/models/qgsprocessingmodelalgorithm.sip.in b/python/core/auto_generated/processing/models/qgsprocessingmodelalgorithm.sip.in
@@ -417,6 +417,30 @@ algorithm ``results`` must be passed.
 Creates a new expression context scope for a child algorithm within the model.
 
 .. seealso:: :py:func:`variablesForChildAlgorithm`
+%End
+
+    QVariantMap variables() const;
+%Docstring
+Returns the map of custom expression context variables defined for this model.
+
+These variables are added to the model's expression context scope, allowing for preset
+"constant" expression variables to be utilised within the model.
+
+.. seealso:: :py:func:`setVariables`
+
+.. versionadded:: 3.8
+%End
+
+    void setVariables( const QVariantMap &variables );
+%Docstring
+Sets the map of custom expression context ``variables`` for this model.
+
+These variables are added to the model's expression context scope, allowing for preset
+"constant" expression variables to be utilised within the model.
+
+.. seealso:: :py:func:`variables`
+
+.. versionadded:: 3.8
 %End
 
   protected:

diff --git a/src/core/expression/qgsexpressioncontextutils.cpp b/src/core/expression/qgsexpressioncontextutils.cpp
@@ -777,6 +777,14 @@ QgsExpressionContextScope *QgsExpressionContextUtils::processingModelAlgorithmSc
   modelScope->addVariable( QgsExpressionContextScope::StaticVariable( QStringLiteral( "model_folder" ), QDir::toNativeSeparators( modelFolder ), true, true ) );
   modelScope->addVariable( QgsExpressionContextScope::StaticVariable( QStringLiteral( "model_name" ), model->displayName(), true ) );
   modelScope->addVariable( QgsExpressionContextScope::StaticVariable( QStringLiteral( "model_group" ), model->group(), true ) );
+
+  // custom variables
+  const QVariantMap customVariables = model->variables();
+  for ( auto it = customVariables.constBegin(); it != customVariables.constEnd(); ++it )
+  {
+    modelScope->addVariable( QgsExpressionContextScope::StaticVariable( it.key(), it.value(), true ) );
+  }
+
   return modelScope.release();
 }
 

diff --git a/src/core/processing/models/qgsprocessingmodelalgorithm.cpp b/src/core/processing/models/qgsprocessingmodelalgorithm.cpp
@@ -1059,6 +1059,8 @@ QVariant QgsProcessingModelAlgorithm::toVariant() const
   }
   map.insert( QStringLiteral( "parameterDefinitions" ), paramDefMap );
 
+  map.insert( QStringLiteral( "modelVariables" ), mVariables );
+
   return map;
 }
 
@@ -1071,6 +1073,8 @@ bool QgsProcessingModelAlgorithm::loadVariant( const QVariant &model )
   mModelGroupId = map.value( QStringLiteral( "model_group" ) ).toString();
   mHelpContent = map.value( QStringLiteral( "help" ) ).toMap();
 
+  mVariables = map.value( QStringLiteral( "modelVariables" ) ).toMap();
+
   mChildAlgorithms.clear();
   QVariantMap childMap = map.value( QStringLiteral( "children" ) ).toMap();
   QVariantMap::const_iterator childIt = childMap.constBegin();
@@ -1444,5 +1448,15 @@ QgsProcessingAlgorithm *QgsProcessingModelAlgorithm::createInstance() const
   return alg;
 }
 
+QVariantMap QgsProcessingModelAlgorithm::variables() const
+{
+  return mVariables;
+}
+
+void QgsProcessingModelAlgorithm::setVariables( const QVariantMap &variables )
+{
+  mVariables = variables;
+}
+
 ///@endcond
 
diff --git a/src/core/processing/models/qgsprocessingmodelalgorithm.h b/src/core/processing/models/qgsprocessingmodelalgorithm.h
@@ -376,6 +376,28 @@ class CORE_EXPORT QgsProcessingModelAlgorithm : public QgsProcessingAlgorithm
     QgsExpressionContextScope *createExpressionContextScopeForChildAlgorithm( const QString &childId, QgsProcessingContext &context, const QVariantMap &modelParameters = QVariantMap(),
         const QVariantMap &results = QVariantMap() ) const SIP_FACTORY;
 
+    /**
+     * Returns the map of custom expression context variables defined for this model.
+     *
+     * These variables are added to the model's expression context scope, allowing for preset
+     * "constant" expression variables to be utilised within the model.
+     *
+     * \see setVariables()
+     * \since QGIS 3.8
+     */
+    QVariantMap variables() const;
+
+    /**
+     * Sets the map of custom expression context \a variables for this model.
+     *
+     * These variables are added to the model's expression context scope, allowing for preset
+     * "constant" expression variables to be utilised within the model.
+     *
+     * \see variables()
+     * \since QGIS 3.8
+     */
+    void setVariables( const QVariantMap &variables );
+
   protected:
 
     QgsProcessingAlgorithm *createInstance() const override SIP_FACTORY;
@@ -400,6 +422,8 @@ class CORE_EXPORT QgsProcessingModelAlgorithm : public QgsProcessingAlgorithm
 
     QVariantMap mResults;
 
+    QVariantMap mVariables;
+
     void dependsOnChildAlgorithmsRecursive( const QString &childId, QSet<QString> &depends ) const;
     void dependentChildAlgorithmsRecursive( const QString &childId, QSet<QString> &depends ) const;
 

diff --git a/tests/src/analysis/testqgsprocessing.cpp b/tests/src/analysis/testqgsprocessing.cpp
@@ -6006,6 +6006,12 @@ void TestQgsProcessing::modelScope()
   QgsProcessingContext pc;
 
   QgsProcessingModelAlgorithm alg( "test", "testGroup" );
+
+  QVariantMap variables;
+  variables.insert( QStringLiteral( "v1" ), 5 );
+  variables.insert( QStringLiteral( "v2" ), QStringLiteral( "aabbccd" ) );
+  alg.setVariables( variables );
+
   QVariantMap params;
   params.insert( QStringLiteral( "a_param" ), 5 );
   std::unique_ptr< QgsExpressionContextScope > scope( QgsExpressionContextUtils::processingModelAlgorithmScope( &alg, params, pc ) );
@@ -6016,6 +6022,8 @@ void TestQgsProcessing::modelScope()
   QVERIFY( scope->hasVariable( QStringLiteral( "model_folder" ) ) );
   QCOMPARE( scope->variable( QStringLiteral( "model_path" ) ).toString(), QString() );
   QCOMPARE( scope->variable( QStringLiteral( "model_folder" ) ).toString(), QString() );
+  QCOMPARE( scope->variable( QStringLiteral( "v1" ) ).toInt(), 5 );
+  QCOMPARE( scope->variable( QStringLiteral( "v2" ) ).toString(), QStringLiteral( "aabbccd" ) );
 
   QgsProject p;
   pc.setProject( &p );
@@ -6590,6 +6598,11 @@ void TestQgsProcessing::modelerAlgorithm()
   QgsProcessingModelAlgorithm alg5( "test", "testGroup" );
   alg5.helpContent().insert( "author", "me" );
   alg5.helpContent().insert( "usage", "run" );
+  QVariantMap variables;
+  variables.insert( QStringLiteral( "v1" ), 5 );
+  variables.insert( QStringLiteral( "v2" ), QStringLiteral( "aabbccd" ) );
+  alg5.setVariables( variables );
+  QCOMPARE( alg5.variables(), variables );
   QgsProcessingModelChildAlgorithm alg5c1;
   alg5c1.setChildId( "cx1" );
   alg5c1.setAlgorithmId( "buffer" );
@@ -6638,6 +6651,7 @@ void TestQgsProcessing::modelerAlgorithm()
   QCOMPARE( alg6.name(), QStringLiteral( "test" ) );
   QCOMPARE( alg6.group(), QStringLiteral( "testGroup" ) );
   QCOMPARE( alg6.helpContent(), alg5.helpContent() );
+  QCOMPARE( alg6.variables(), variables );
   QgsProcessingModelChildAlgorithm alg6c1 = alg6.childAlgorithm( "cx1" );
   QCOMPARE( alg6c1.childId(), QStringLiteral( "cx1" ) );
   QCOMPARE( alg6c1.algorithmId(), QStringLiteral( "buffer" ) );

diff --git a/tests/testdata/points_gpkg.gpkg b/tests/testdata/points_gpkg.gpkg