[FEATURE] use expressions engine to evaluate feature actions

work done for Regione Toscana-SIGTA

Author: brushtyler

src/app/qgsattributeactiondialog.cpp

@@ -22,11 +22,12 @@ back to QgsVectorLayer.
 
 #include "qgsattributeactiondialog.h"
 #include "qgsattributeaction.h"
+#include "qgsexpressionbuilderdialog.h"
 
 #include <QFileDialog>
 #include <QHeaderView>
 #include <QMessageBox>
-
+#include <QSettings>
 
 QgsAttributeActionDialog::QgsAttributeActionDialog( QgsAttributeAction* actions,
     const QgsFieldMap& fields,
@@ -50,6 +51,7 @@ QgsAttributeActionDialog::QgsAttributeActionDialog( QgsAttributeAction* actions,
   connect( insertButton, SIGNAL( clicked() ), this, SLOT( insert() ) );
   connect( updateButton, SIGNAL( clicked() ), this, SLOT( update() ) );
   connect( insertFieldButton, SIGNAL( clicked() ), this, SLOT( insertField() ) );
+  connect( insertExpressionButton, SIGNAL( clicked() ), this, SLOT( insertExpression() ) );
 
   init();
   // Populate the combo box with the field names. Will the field names
@@ -143,16 +145,36 @@ void QgsAttributeActionDialog::swapRows( int row1, int row2 )
 
 void QgsAttributeActionDialog::browse()
 {
-  // Popup a file browser and place the results into the actionName
-  // widget
-
+  // Popup a file browser and place the results into the action widget
   QString action = QFileDialog::getOpenFileName(
                      this, tr( "Select an action", "File dialog window title" ) );
 
   if ( !action.isNull() )
     actionAction->insert( action );
 }
 
+void QgsAttributeActionDialog::insertExpression()
+{
+  QString selText = actionAction->selectedText();
+
+  // edit the selected expression if there's one
+  if ( selText.startsWith( "[%" ) && selText.endsWith( "%]" ) )
+    selText = selText.mid( 2, selText.size() - 3 );
+
+  // display the expression builder
+  QgsExpressionBuilderDialog dlg( mActions->layer(), selText, this );
+  dlg.setWindowTitle( tr( "Insert expression" ) );
+  if ( dlg.exec() == QDialog::Accepted )
+  {
+    QString expression =  dlg.expressionBuilder()->getExpressionString();
+    //Only add the expression if the user has entered some text.
+    if ( !expression.isEmpty() )
+    {
+      actionAction->insert( "[%" + expression + "%]" );
+    }
+  }
+}
+
 void QgsAttributeActionDialog::remove()
 {
   QList<QTableWidgetItem *> selection = attributeActionTable->selectedItems();
@@ -234,13 +256,14 @@ void QgsAttributeActionDialog::update()
 
 void QgsAttributeActionDialog::insertField()
 {
-  // Take the selected field, preprend a % and insert into the action
-  // field at the cursor position
+  // Convert the selected field to an expression and
+  // insert it into the action at the cursor position
 
   if ( !fieldComboBox->currentText().isNull() )
   {
-    QString field( "%" );
+    QString field = "[% \"";
     field += fieldComboBox->currentText();
+    field += "\" %]";
     actionAction->insert( field );
   }
 }

src/app/qgsattributeactiondialog.h

@@ -50,6 +50,7 @@ class QgsAttributeActionDialog: public QWidget, private Ui::QgsAttributeActionDi
     void remove();
     void insert();
     void insertField();
+    void insertExpression();
     void apply();
     void update();
     void itemSelectionChanged();

src/app/qgsfeatureaction.cpp

@@ -36,7 +36,7 @@ QgsFeatureAction::QgsFeatureAction( const QString &name, QgsFeature &f, QgsVecto
 
 void QgsFeatureAction::execute()
 {
-  mLayer->actions()->doAction( mAction, mFeature.attributeMap(), mIdx );
+  mLayer->actions()->doAction( mAction, mFeature, mIdx );
 }
 
 QgsAttributeDialog *QgsFeatureAction::newDialog( bool cloneFeature )

src/app/qgsidentifyresults.cpp

@@ -429,7 +429,7 @@ void QgsIdentifyResults::contextMenuEvent( QContextMenuEvent* event )
 
   mActionPopup = new QMenu();
 
-  int idx = 0;
+  int idx = -1;
   QTreeWidgetItem *featItem = featureItem( item );
   if ( featItem )
   {
@@ -549,17 +549,15 @@ void QgsIdentifyResults::deactivate()
 
 void QgsIdentifyResults::doAction( QTreeWidgetItem *item, int action )
 {
-  int idx;
-  QgsAttributeMap attributes;
-  QTreeWidgetItem *featItem = retrieveAttributes( item, attributes, idx );
+  QTreeWidgetItem *featItem = featureItem( item );
   if ( !featItem )
     return;
 
   QgsVectorLayer *layer = qobject_cast<QgsVectorLayer *>( featItem->parent()->data( 0, Qt::UserRole ).value<QObject *>() );
   if ( !layer )
     return;
 
-  idx = -1;
+  int idx = -1;
   if ( item->parent() == featItem )
   {
     QString fieldName = item->data( 0, Qt::DisplayRole ).toString();
@@ -574,7 +572,8 @@ void QgsIdentifyResults::doAction( QTreeWidgetItem *item, int action )
     }
   }
 
-  layer->actions()->doAction( action, attributes, idx );
+  int featIdx = featItem->data( 0, Qt::UserRole + 1 ).toInt();
+  layer->actions()->doAction( action, mFeatures[ featIdx ], idx );
 }
 
 QTreeWidgetItem *QgsIdentifyResults::featureItem( QTreeWidgetItem *item )

src/core/qgsattributeaction.cpp

@@ -22,15 +22,23 @@
  *                                                                         *
  ***************************************************************************/
 
-#include <QList>
-
-#include <QStringList>
-#include <QDomElement>
-
 #include "qgsattributeaction.h"
 #include "qgspythonrunner.h"
 #include "qgsrunprocess.h"
 #include "qgsvectorlayer.h"
+#include "qgsproject.h"
+#include <qgslogger.h>
+#include "qgsexpression.h"
+
+#include <QList>
+#include <QStringList>
+#include <QDomElement>
+#include <QSettings>
+#include <QDesktopServices>
+#include <QUrl>
+#include <QDir>
+#include <QFileInfo>
+
 
 void QgsAttributeAction::addAction( QgsAction::ActionType type, QString name, QString action, bool capture )
 {
@@ -44,7 +52,6 @@ void QgsAttributeAction::doAction( int index, const QgsAttributeMap &attributes,
     return;
 
   const QgsAction &action = at( index );
-
   if ( !action.runable() )
     return;
 
@@ -58,29 +65,67 @@ void QgsAttributeAction::doAction( int index, const QgsAttributeMap &attributes,
   // the UI and the code in this function to select on the
   // action.capture() return value.
 
-  // The QgsRunProcess instance created by this static function
-  // deletes itself when no longer needed.
   QString expandedAction = expandAction( action.action(), attributes, defaultValueIndex );
+  if ( expandedAction.isEmpty() )
+    return;
+
+  QgsAction newAction( action.type(), action.name(), expandedAction, action.capture() );
+  runAction( newAction, executePython );
+}
+
+void QgsAttributeAction::doAction( int index, QgsFeature &feat, int defaultValueIndex )
+{
+  QMap<QString, QVariant> substitutionMap;
+  if ( defaultValueIndex >= 0 )
+    substitutionMap.insert( "$currfield", QVariant( defaultValueIndex ) );
+
+  doAction( index, feat, &substitutionMap );
+}
+
+void QgsAttributeAction::doAction( int index, QgsFeature &feat,
+                                   const QMap<QString, QVariant> *substitutionMap )
+{
+  if ( index < 0 || index >= size() )
+    return;
+
+  const QgsAction &action = at( index );
+  if ( !action.runable() )
+    return;
+
+  // search for expressions while expanding actions
+  QString expandedAction = expandAction( action.action(), feat, substitutionMap );
+  if ( expandedAction.isEmpty() )
+    return;
+
+  QgsAction newAction( action.type(), action.name(), expandedAction, action.capture() );
+  runAction( newAction );
+}
+
+void QgsAttributeAction::runAction( const QgsAction &action, void ( *executePython )( const QString & ) )
+{
   if ( action.type() == QgsAction::GenericPython )
   {
     if ( executePython )
     {
       // deprecated
-      executePython( expandedAction );
+      executePython( action.action() );
     }
     else if ( smPythonExecute )
     {
       // deprecated
-      smPythonExecute( expandedAction );
+      smPythonExecute( action.action() );
     }
     else
     {
-      QgsPythonRunner::run( expandedAction );
+      // TODO: capture output from QgsPythonRunner
+      QgsPythonRunner::run( action.action() );
     }
   }
   else
   {
-    QgsRunProcess::create( expandedAction, action.capture() );
+    // The QgsRunProcess instance created by this static function
+    // deletes itself when no longer needed.
+    QgsRunProcess::create( action.action(), action.capture() );
   }
 }
 
@@ -89,7 +134,7 @@ QString QgsAttributeAction::expandAction( QString action, const QgsAttributeMap
 {
   // This function currently replaces all %% characters in the action
   // with the value from values[clickedOnValue].second, and then
-  // searches for all strings that go %attribite_name, where
+  // searches for all strings that go %attribute_name, where
   // attribute_name is found in values[x].first, and replaces any that
   // it finds by values[s].second.
 
@@ -134,6 +179,63 @@ QString QgsAttributeAction::expandAction( QString action, const QgsAttributeMap
   return expanded_action;
 }
 
+QString QgsAttributeAction::expandAction( QString action, QgsFeature &feat, const QMap<QString, QVariant> *substitutionMap )
+{
+  // This function currently replaces each expression between [% and %]
+  // in the action with the result of its evaluation on the feature
+  // passed as argument.
+
+  // Additional substitutions can be passed through the substitutionMap
+  // parameter
+
+  QString expr_action;
+
+  int index = 0;
+  while ( index < action.size() )
+  {
+    QRegExp rx = QRegExp( "\\[%([^\\]]+)%\\]" );
+
+    int pos = rx.indexIn( action, index );
+    if ( pos < 0 )
+      break;
+
+    int start = index;
+    index = pos + rx.matchedLength();
+
+    QString to_replace = rx.cap(1).trimmed();
+    QgsDebugMsg( "Found expression:" + to_replace );
+
+    if ( substitutionMap && substitutionMap->contains( to_replace ) )
+    {
+      expr_action += action.mid( start, pos - start ) + substitutionMap->value( to_replace ).toString();
+      continue;
+    }
+
+    QgsExpression* exp = new QgsExpression( to_replace );
+    if ( exp->hasParserError() )
+    {
+      QgsDebugMsg( "Expression parser error:" + exp->parserErrorString() );
+      expr_action += action.mid( start, index - start );
+      continue;
+    }
+
+    QVariant result = exp->evaluate( &feat, mLayer->pendingFields() );
+    if ( exp->hasEvalError() )
+    {
+      QgsDebugMsg( "Expression parser eval error:" + exp->evalErrorString() );
+      expr_action += action.mid( start, index - start );
+      continue;
+    }
+
+    QgsDebugMsg( "Expression result is: " + result.toString() );
+    expr_action += action.mid( start, pos - start ) + result.toString();
+  }
+
+  expr_action += action.mid( index );
+  return expr_action;
+}
+
+
 bool QgsAttributeAction::writeXML( QDomNode& layer_node, QDomDocument& doc ) const
 {
   QDomElement aActions = doc.createElement( "attributeactions" );