[FEATURE][composer] Allow evaluation of QGIS expressions inside html …

…item source. Expressions are evaluated before HTML is rendered, allowing the expression results to modify how the HTML content is rendered. Sponsored by City of Uster, Switzerland.

python/core/composer/qgscomposerhtml.sip

@@ -73,6 +73,26 @@ class QgsComposerHtml: QgsComposerMultiFrame
      * @note added in 2.5
      */
     QString html() const;
+
+    /**Returns whether html item will evaluate QGIS expressions prior to rendering
+     * the HTML content. If set, any content inside [% %] tags will be
+     * treated as a QGIS expression and evaluated against the current atlas
+     * feature.
+     * @returns true if html item will evaluate expressions in the content
+     * @see setEvaluateExpressions
+     * @note added in QGIS 2.5
+     */
+    bool evaluateExpressions() const;
+
+    /**Sets whether the html item will evaluate QGIS expressions prior to rendering
+     * the HTML content. If set, any content inside [% %] tags will be
+     * treated as a QGIS expression and evaluated against the current atlas
+     * feature.
+     * @param evaluateExpressions set to true to evaluate expressions in the HTML content
+     * @see evaluateExpressions
+     * @note added in QGIS 2.5
+     */
+    void setEvaluateExpressions( bool evaluateExpressions );    
 
     QSizeF totalSize() const;
     void render( QPainter* p, const QRectF& renderExtent );

src/app/composer/qgscomposerhtmlwidget.cpp

@@ -18,6 +18,7 @@
 #include "qgscomposermultiframecommand.h"
 #include "qgscomposerhtml.h"
 #include "qgscomposition.h"
+#include "qgsexpressionbuilderdialog.h"
 #include <QFileDialog>
 #include <QSettings>
 #include <Qsci/qsciscintilla.h>
@@ -77,6 +78,7 @@ void QgsComposerHtmlWidget::blockSignals( bool block )
   mHtmlEditor->blockSignals( block );
   mRadioManualSource->blockSignals( block );
   mRadioUrlSource->blockSignals( block );
+  mEvaluateExpressionsCheckbox->blockSignals( block );
 }
 
 void QgsComposerHtmlWidget::on_mUrlLineEdit_editingFinished()
@@ -133,6 +135,24 @@ void QgsComposerHtmlWidget::on_mResizeModeComboBox_currentIndexChanged( int inde
   mAddFramePushButton->setEnabled( mHtml->resizeMode() == QgsComposerMultiFrame::UseExistingFrames );
 }
 
+void QgsComposerHtmlWidget::on_mEvaluateExpressionsCheckbox_toggled( bool checked )
+{
+  if ( !mHtml )
+  {
+    return;
+  }
+
+  QgsComposition* composition = mHtml->composition();
+  if ( composition )
+  {
+    blockSignals( true );
+    composition->beginMultiFrameCommand( mHtml, tr( "Evaluate expressions changed" ) );
+    mHtml->setEvaluateExpressions( checked );
+    composition->endMultiFrameCommand();
+    blockSignals( false );
+  }
+}
+
 void QgsComposerHtmlWidget::on_mUseSmartBreaksCheckBox_toggled( bool checked )
 {
   if ( !mHtml )
@@ -158,7 +178,15 @@ void QgsComposerHtmlWidget::on_mMaxDistanceSpinBox_valueChanged( double val )
     return;
   }
 
-  mHtml->setMaxBreakDistance( val );
+  QgsComposition* composition = mHtml->composition();
+  if ( composition )
+  {
+    blockSignals( true );
+    composition->beginMultiFrameCommand( mHtml, tr( "Page break distance changed" ) );
+    mHtml->setMaxBreakDistance( val );
+    composition->endMultiFrameCommand();
+    blockSignals( false );
+  }
 }
 
 void QgsComposerHtmlWidget::htmlEditorChanged()
@@ -168,7 +196,16 @@ void QgsComposerHtmlWidget::htmlEditorChanged()
     return;
   }
 
-  mHtml->setHtml( mHtmlEditor->text() );
+  QgsComposition* composition = mHtml->composition();
+  if ( composition )
+  {
+    blockSignals( true );
+    composition->beginMultiFrameCommand( mHtml, tr( "HTML changed" ) );
+    mHtml->setHtml( mHtmlEditor->text() );
+    composition->endMultiFrameCommand();
+    blockSignals( false );
+  }
+
 }
 
 void QgsComposerHtmlWidget::on_mRadioManualSource_clicked( bool checked )
@@ -178,8 +215,17 @@ void QgsComposerHtmlWidget::on_mRadioManualSource_clicked( bool checked )
     return;
   }
 
-  mHtml->setContentMode( checked ? QgsComposerHtml::ManualHtml : QgsComposerHtml::Url );
+  QgsComposition* composition = mHtml->composition();
+  if ( composition )
+  {
+    blockSignals( true );
+    composition->beginMultiFrameCommand( mHtml, tr( "HTML source changed" ) );
+    mHtml->setContentMode( checked ? QgsComposerHtml::ManualHtml : QgsComposerHtml::Url );
+    composition->endMultiFrameCommand();
+    blockSignals( false );
+  }
   mHtmlEditor->setEnabled( checked );
+  mInsertExpressionButton->setEnabled( checked );
   mUrlLineEdit->setEnabled( !checked );
   mFileToolButton->setEnabled( !checked );
 
@@ -193,14 +239,73 @@ void QgsComposerHtmlWidget::on_mRadioUrlSource_clicked( bool checked )
     return;
   }
 
-  mHtml->setContentMode( checked ? QgsComposerHtml::Url : QgsComposerHtml::ManualHtml );
+  QgsComposition* composition = mHtml->composition();
+  if ( composition )
+  {
+    blockSignals( true );
+    composition->beginMultiFrameCommand( mHtml, tr( "HTML source changed" ) );
+    mHtml->setContentMode( checked ? QgsComposerHtml::Url : QgsComposerHtml::ManualHtml );
+    composition->endMultiFrameCommand();
+    blockSignals( false );
+  }
   mHtmlEditor->setEnabled( !checked );
+  mInsertExpressionButton->setEnabled( !checked );
   mUrlLineEdit->setEnabled( checked );
   mFileToolButton->setEnabled( checked );
 
   mHtml->loadHtml();
 }
 
+void QgsComposerHtmlWidget::on_mInsertExpressionButton_clicked()
+{
+  if ( !mHtml )
+  {
+    return;
+  }
+
+  int line = 0;
+  int index = 0;
+  QString selText;
+  if ( mHtmlEditor->hasSelectedText() )
+  {
+    selText = mHtmlEditor->selectedText();
+
+    // edit the selected expression if there's one
+    if ( selText.startsWith( "[%" ) && selText.endsWith( "%]" ) )
+      selText = selText.mid( 2, selText.size() - 4 );
+  }
+  else
+  {
+    mHtmlEditor->getCursorPosition( &line, &index );
+  }
+
+  // use the atlas coverage layer, if any
+  QgsVectorLayer* coverageLayer = atlasCoverageLayer();
+  QgsExpressionBuilderDialog exprDlg( coverageLayer, selText, this );
+  exprDlg.setWindowTitle( tr( "Insert expression" ) );
+  if ( exprDlg.exec() == QDialog::Accepted )
+  {
+    QString expression =  exprDlg.expressionText();
+    QgsComposition* composition = mHtml->composition();
+    if ( !expression.isEmpty() && composition )
+    {
+      blockSignals( true );
+      composition->beginMultiFrameCommand( mHtml, tr( "HTML source changed" ) );
+      if ( mHtmlEditor->hasSelectedText() )
+      {
+        mHtmlEditor->replaceSelectedText( "[%" + expression + "%]" );
+      }
+      else
+      {
+        mHtmlEditor->insertAt( "[%" + expression + "%]", line, index );
+      }
+      composition->endMultiFrameCommand();
+      blockSignals( false );
+    }
+  }
+
+}
+
 void QgsComposerHtmlWidget::on_mReloadPushButton_clicked()
 {
   if ( !mHtml )
@@ -244,6 +349,7 @@ void QgsComposerHtmlWidget::setGuiElementValues()
   blockSignals( true );
   mUrlLineEdit->setText( mHtml->url().toString() );
   mResizeModeComboBox->setCurrentIndex( mResizeModeComboBox->findData( mHtml->resizeMode() ) );
+  mEvaluateExpressionsCheckbox->setChecked( mHtml->evaluateExpressions() );
   mUseSmartBreaksCheckBox->setChecked( mHtml->useSmartBreaks() );
   mMaxDistanceSpinBox->setValue( mHtml->maxBreakDistance() );
 
@@ -255,5 +361,6 @@ void QgsComposerHtmlWidget::setGuiElementValues()
   mFileToolButton->setEnabled( mHtml->contentMode() == QgsComposerHtml::Url );
   mRadioManualSource->setChecked( mHtml->contentMode() == QgsComposerHtml::ManualHtml );
   mHtmlEditor->setEnabled( mHtml->contentMode() == QgsComposerHtml::ManualHtml );
+  mInsertExpressionButton->setEnabled( mHtml->contentMode() == QgsComposerHtml::ManualHtml );
   blockSignals( false );
 }

src/app/composer/qgscomposerhtmlwidget.h

@@ -33,11 +33,13 @@ class QgsComposerHtmlWidget: public QgsComposerItemBaseWidget, private Ui::QgsCo
     void on_mUrlLineEdit_editingFinished();
     void on_mFileToolButton_clicked();
     void on_mResizeModeComboBox_currentIndexChanged( int index );
+    void on_mEvaluateExpressionsCheckbox_toggled( bool checked );
     void on_mUseSmartBreaksCheckBox_toggled( bool checked );
     void on_mMaxDistanceSpinBox_valueChanged( double val );
     void htmlEditorChanged();
     void on_mRadioManualSource_clicked( bool checked );
     void on_mRadioUrlSource_clicked( bool checked );
+    void on_mInsertExpressionButton_clicked();
 
     void on_mReloadPushButton_clicked();
     void on_mAddFramePushButton_clicked();

src/core/composer/qgscomposerhtml.cpp

@@ -19,6 +19,7 @@
 #include "qgsaddremovemultiframecommand.h"
 #include "qgsnetworkaccessmanager.h"
 #include "qgsmessagelog.h"
+#include "qgsexpression.h"
 
 #include <QCoreApplication>
 #include <QPainter>
@@ -33,8 +34,11 @@ QgsComposerHtml::QgsComposerHtml( QgsComposition* c, bool createUndoCommands ):
     mLoaded( false ),
     mHtmlUnitsToMM( 1.0 ),
     mRenderedPage( 0 ),
+    mEvaluateExpressions( true ),
     mUseSmartBreaks( true ),
-    mMaxBreakDistance( 10 )
+    mMaxBreakDistance( 10 ),
+    mExpressionFeature( 0 ),
+    mExpressionLayer( 0 )
 {
   mHtmlUnitsToMM = htmlUnitsToMM();
   mWebPage = new QWebPage();
@@ -45,6 +49,18 @@ QgsComposerHtml::QgsComposerHtml( QgsComposition* c, bool createUndoCommands ):
     QObject::connect( mComposition, SIGNAL( itemRemoved( QgsComposerItem* ) ), this, SLOT( handleFrameRemoval( QgsComposerItem* ) ) );
     connect( mComposition, SIGNAL( refreshItemsTriggered() ), this, SLOT( loadHtml() ) );
   }
+
+  if ( mComposition && mComposition->atlasMode() == QgsComposition::PreviewAtlas )
+  {
+    //a html item added while atlas preview is enabled needs to have the expression context set,
+    //otherwise fields in the html aren't correctly evaluated until atlas preview feature changes (#9457)
+    setExpressionContext( mComposition->atlasComposition().currentFeature(), mComposition->atlasComposition().coverageLayer() );
+  }
+
+  //connect to atlas feature changes
+  //to update the expression context
+  connect( &mComposition->atlasComposition(), SIGNAL( featureChanged( QgsFeature* ) ), this, SLOT( refreshExpressionContext() ) );
+
 }
 
 QgsComposerHtml::QgsComposerHtml(): QgsComposerMultiFrame( 0, false ),
@@ -54,7 +70,9 @@ QgsComposerHtml::QgsComposerHtml(): QgsComposerMultiFrame( 0, false ),
     mHtmlUnitsToMM( 1.0 ),
     mRenderedPage( 0 ),
     mUseSmartBreaks( true ),
-    mMaxBreakDistance( 10 )
+    mMaxBreakDistance( 10 ),
+    mExpressionFeature( 0 ),
+    mExpressionLayer( 0 )
 {
 }
 
@@ -80,6 +98,12 @@ void QgsComposerHtml::setHtml( const QString html )
   mHtml = html;
 }
 
+void QgsComposerHtml::setEvaluateExpressions( bool evaluateExpressions )
+{
+  mEvaluateExpressions = evaluateExpressions;
+  loadHtml();
+}
+
 QString QgsComposerHtml::fetchHtml( QUrl url )
 {
   QUrl nextUrlToFetch = url;
@@ -151,6 +175,12 @@ void QgsComposerHtml::loadHtml()
       break;
   }
 
+  //evaluate expressions
+  if ( mEvaluateExpressions )
+  {
+    loadedHtml = QgsExpression::replaceExpressionText( loadedHtml, mExpressionFeature, mExpressionLayer );
+  }
+
   mLoaded = false;
   //set html, using the specified url as base if in Url mode
   mWebPage->mainFrame()->setHtml( loadedHtml, mContentMode == QgsComposerHtml::Url ? QUrl( mUrl ) : QUrl() );
@@ -360,6 +390,7 @@ bool QgsComposerHtml::writeXML( QDomElement& elem, QDomDocument & doc, bool igno
   htmlElem.setAttribute( "contentMode",  QString::number(( int ) mContentMode ) );
   htmlElem.setAttribute( "url", mUrl.toString() );
   htmlElem.setAttribute( "html", mHtml );
+  htmlElem.setAttribute( "evaluateExpressions", mEvaluateExpressions ? "true" : "false" );
   htmlElem.setAttribute( "useSmartBreaks", mUseSmartBreaks ? "true" : "false" );
   htmlElem.setAttribute( "maxBreakDistance", QString::number( mMaxBreakDistance ) );
 
@@ -384,6 +415,7 @@ bool QgsComposerHtml::readXML( const QDomElement& itemElem, const QDomDocument&
   {
     mContentMode = QgsComposerHtml::Url;
   }
+  mEvaluateExpressions = itemElem.attribute( "evaluateExpressions", "true" ) == "true" ? true : false;
   mUseSmartBreaks = itemElem.attribute( "useSmartBreaks", "true" ) == "true" ? true : false;
   mMaxBreakDistance = itemElem.attribute( "maxBreakDistance", "10" ).toDouble();
   mHtml = itemElem.attribute( "html" );
@@ -399,3 +431,27 @@ bool QgsComposerHtml::readXML( const QDomElement& itemElem, const QDomDocument&
   emit changed();
   return true;
 }
+
+void QgsComposerHtml::setExpressionContext( QgsFeature* feature, QgsVectorLayer* layer )
+{
+  mExpressionFeature = feature;
+  mExpressionLayer = layer;
+}
+
+void QgsComposerHtml::refreshExpressionContext()
+{
+  QgsVectorLayer * vl = 0;
+  QgsFeature* feature = 0;
+
+  if ( mComposition->atlasComposition().enabled() )
+  {
+    vl = mComposition->atlasComposition().coverageLayer();
+  }
+  if ( mComposition->atlasMode() != QgsComposition::AtlasOff )
+  {
+    feature = mComposition->atlasComposition().currentFeature();
+  }
+
+  setExpressionContext( feature, vl );
+  loadHtml();
+}