Fix #9520 (bbox filter doesn't work applied on a WFS datasource)

Currently the bbox must have syntax bbox($geometry, geomFromWKT('...'))

src/core/qgsogcutils.cpp

@@ -2100,15 +2100,61 @@ static bool isGeometryColumn( const QgsExpression::Node* node )
   return fd->name() == "$geometry";
 }
 
+static QgsGeometry* geometryFromConstExpr( const QgsExpression::Node* node )
+{
+  // Right now we support only geomFromWKT(' ..... ')
+  // Ideally we should support any constant sub-expression (not dependant on feature's geometry or attributes)
+
+  if ( node->nodeType() == QgsExpression::ntFunction )
+  {
+    const QgsExpression::NodeFunction* fnNode = static_cast<const QgsExpression::NodeFunction*>( node );
+    QgsExpression::Function* fnDef = QgsExpression::Functions()[fnNode->fnIndex()];
+    if ( fnDef->name() == "geomFromWKT" )
+    {
+      const QList<QgsExpression::Node*>& args = fnNode->args()->list();
+      if ( args[0]->nodeType() == QgsExpression::ntLiteral )
+      {
+        QString wkt = static_cast<const QgsExpression::NodeLiteral*>( args[0] )->value().toString();
+        return QgsGeometry::fromWkt( wkt );
+      }
+    }
+  }
+  return 0;
+}
+
 
 QDomElement QgsOgcUtils::expressionFunctionToOgcFilter( const QgsExpression::NodeFunction* node, QDomDocument& doc, QString& errorMessage )
 {
   QgsExpression::Function* fd = QgsExpression::Functions()[node->fnIndex()];
 
   if ( fd->name() == "bbox" )
   {
-    errorMessage = QString( "<BBOX> is currently not supported." );
-    return QDomElement();
+    QList<QgsExpression::Node*> argNodes = node->args()->list();
+    Q_ASSERT( argNodes.count() == 2 ); // binary spatial ops must have two args
+
+    QgsGeometry* geom = geometryFromConstExpr( argNodes[1] );
+    if ( geom && isGeometryColumn( argNodes[0] ) )
+    {
+      QgsRectangle rect = geom->boundingBox();
+      delete geom;
+
+      QDomElement elemBox = rectangleToGMLBox( &rect, doc );
+
+      QDomElement geomProperty = doc.createElement( "ogc:PropertyName" );
+      geomProperty.appendChild( doc.createTextNode( "geometry" ) );
+
+      QDomElement funcElem = doc.createElement( "ogr:BBOX" );
+      funcElem.appendChild( geomProperty );
+      funcElem.appendChild( elemBox );
+      return funcElem;
+    }
+    else
+    {
+      delete geom;
+
+      errorMessage = QString( "<BBOX> is currently supported only in form: bbox($geometry, geomFromWKT('...'))" );
+      return QDomElement();
+    }
   }
 
   if ( isBinarySpatialOperator( fd->name() ) )

src/providers/wfs/qgswfscapabilities.cpp

@@ -15,6 +15,7 @@
 #include "qgswfscapabilities.h"
 #include "qgsexpression.h"
 #include "qgslogger.h"
+#include "qgsmessagelog.h"
 #include "qgsnetworkaccessmanager.h"
 #include "qgsogcutils.h"
 #include <QDomDocument>
@@ -104,7 +105,12 @@ QString QgsWFSCapabilities::uriGetFeature( QString typeName, QString crsString,
     {
       //if not, if must be a QGIS expression
       QgsExpression filterExpression( filter );
-      QDomElement filterElem = QgsOgcUtils::expressionToOgcFilter( filterExpression, filterDoc );
+      QString errorMsg;
+      QDomElement filterElem = QgsOgcUtils::expressionToOgcFilter( filterExpression, filterDoc, &errorMsg );
+      if ( !errorMsg.isEmpty() )
+      {
+        QgsMessageLog::logMessage( "Expression to OGC Filter error: " + errorMsg, "WFS" );
+      }
       if ( !filterElem.isNull() )
       {
         filterDoc.appendChild( filterElem );

src/providers/wfs/qgswfsprovider.cpp

@@ -111,7 +111,7 @@ QgsWFSProvider::QgsWFSProvider( const QString& uri )
     setDataSourceUri( bkUri );
   }
 
-  if ( ! uri.contains( "BBOX" ) )
+  if ( ! uri.contains( "BBOX=" ) )
   { //"Cache Features" option; get all features in layer immediately
     reloadData();
   } //otherwise, defer feature retrieval until layer is first rendered
@@ -241,7 +241,7 @@ QgsFeatureIterator QgsWFSProvider::getFeatures( const QgsFeatureRequest& request
       //ctor cannot initialize because layer object not available then
       if ( ! mInitGro )
       { //did user check "Cache Features" in WFS layer source selection?
-        if ( dsURI.contains( "BBOX" ) )
+        if ( dsURI.contains( "BBOX=" ) )
         { //no: initialize incremental getFeature
           if ( initGetRenderedOnly( rect ) )
           {