[WFS provider] Handle gml:description/identifier/name attributes (fixes

#42660)

src/providers/wfs/qgswfsconstants.cpp

@@ -41,6 +41,7 @@ const QString QgsWFSConstants::URI_PARAM_HIDEDOWNLOADPROGRESSDIALOG( QStringLite
 const QString QgsWFSConstants::URI_PARAM_PAGING_ENABLED( "pagingEnabled" );
 const QString QgsWFSConstants::URI_PARAM_PAGE_SIZE( "pageSize" );
 const QString QgsWFSConstants::URI_PARAM_WFST_1_1_PREFER_COORDINATES( "preferCoordinatesForWfsT11" );
+const QString QgsWFSConstants::URI_PARAM_SKIP_INITIAL_GET_FEATURE( "skipInitialGetFeature" );
 
 const QString QgsWFSConstants::VERSION_AUTO( QStringLiteral( "auto" ) );
 

src/providers/wfs/qgswfsconstants.h

@@ -49,6 +49,7 @@ struct QgsWFSConstants
   static const QString URI_PARAM_PAGING_ENABLED;
   static const QString URI_PARAM_PAGE_SIZE;
   static const QString URI_PARAM_WFST_1_1_PREFER_COORDINATES;
+  static const QString URI_PARAM_SKIP_INITIAL_GET_FEATURE;
 
   //
   static const QString VERSION_AUTO;

src/providers/wfs/qgswfsdatasourceuri.cpp

@@ -171,7 +171,8 @@ QSet<QString> QgsWFSDataSourceURI::unknownParamKeys() const
     QgsWFSConstants::URI_PARAM_HIDEDOWNLOADPROGRESSDIALOG,
     QgsWFSConstants::URI_PARAM_PAGING_ENABLED,
     QgsWFSConstants::URI_PARAM_PAGE_SIZE,
-    QgsWFSConstants::URI_PARAM_WFST_1_1_PREFER_COORDINATES
+    QgsWFSConstants::URI_PARAM_WFST_1_1_PREFER_COORDINATES,
+    QgsWFSConstants::URI_PARAM_SKIP_INITIAL_GET_FEATURE
   };
 
   QSet<QString> l_unknownParamKeys;
@@ -416,6 +417,13 @@ bool QgsWFSDataSourceURI::preferCoordinatesForWfst11() const
          mURI.param( QgsWFSConstants::URI_PARAM_WFST_1_1_PREFER_COORDINATES ).toUpper() == QLatin1String( "TRUE" );
 }
 
+bool QgsWFSDataSourceURI::skipInitialGetFeature() const
+{
+  if ( !mURI.hasParam( QgsWFSConstants::URI_PARAM_SKIP_INITIAL_GET_FEATURE ) )
+    return false;
+  return mURI.param( QgsWFSConstants::URI_PARAM_SKIP_INITIAL_GET_FEATURE ).toUpper() == QLatin1String( "TRUE" );
+}
+
 QString QgsWFSDataSourceURI::build( const QString &baseUri,
                                     const QString &typeName,
                                     const QString &crsString,

src/providers/wfs/qgswfsdatasourceuri.h

@@ -137,6 +137,9 @@ class QgsWFSDataSourceURI
     //! Return set of unknown parameter keys in the URI.
     QSet<QString> unknownParamKeys() const;
 
+    //! Whether the initial GetFeature request, used to determine if gml:description/name/identifiers are used, should be skipped
+    bool skipInitialGetFeature() const;
+
   private:
     QgsDataSourceUri    mURI;
     QgsAuthorizationSettings mAuth;

src/providers/wfs/qgswfsprovider.cpp

@@ -175,10 +175,31 @@ QgsWFSProvider::QgsWFSProvider( const QString &uri, const ProviderOptions &optio
     mShared->setCurrentRect( QgsRectangle() );
   };
 
-  //Failed to detect feature type from describeFeatureType -> get first feature from layer to detect type
-  if ( mShared->mWKBType == QgsWkbTypes::Unknown )
-  {
-    GetGeometryTypeFromOneFeature( true );
+  // For WFS >= 1.1, by default, issue a GetFeature on one feature to check
+  // if gml:description, gml:identifier, gml:name attributes are
+  // present (unless mShared->mURI.skipInitialGetFeature() returns false)
+  // Another reason to issue it if we do not known the exact geometry type
+  // from describeFeatureType()
+  if ( !mShared->mWFSVersion.startsWith( QLatin1String( "1.0" ) ) &&
+       !mShared->mURI.skipInitialGetFeature() )
+  {
+    // Try to see if gml:description, gml:identifier, gml:name attributes are
+    // present. So insert them temporarily in mShared->mFields so that the
+    // GML parser can detect them.
+    const auto addGMLFields = [ = ]( bool forceAdd )
+    {
+      if ( mShared->mFields.indexOf( QStringLiteral( "description" ) ) < 0  && ( forceAdd || mSampleFeatureHasDescription ) )
+        mShared->mFields.append( QgsField( QStringLiteral( "description" ), QVariant::String, QStringLiteral( "xsd:string" ) ) );
+      if ( mShared->mFields.indexOf( QStringLiteral( "identifier" ) ) < 0  && ( forceAdd || mSampleFeatureHasIdentifier ) )
+        mShared->mFields.append( QgsField( QStringLiteral( "identifier" ), QVariant::String, QStringLiteral( "xsd:string" ) ) );
+      if ( mShared->mFields.indexOf( QStringLiteral( "name" ) ) < 0  && ( forceAdd || mSampleFeatureHasName ) )
+        mShared->mFields.append( QgsField( QStringLiteral( "name" ), QVariant::String, QStringLiteral( "xsd:string" ) ) );
+    };
+
+    const QgsFields fieldsBackup = mShared->mFields;
+    addGMLFields( true );
+
+    GetGeometryTypeFromOneFeature( mShared->mWKBType == QgsWkbTypes::Unknown );
 
     // If we still didn't get the geometry type, and have a filter, temporarily
     // disable the filter.
@@ -193,6 +214,13 @@ QgsWFSProvider::QgsWFSProvider( const QString &uri, const ProviderOptions &optio
     }
     else if ( mShared->mWKBType == QgsWkbTypes::Unknown )
       GetGeometryTypeFromOneFeature( false );
+
+    // Edit the final mFields to add the description, identifier, name fields
+    // if they were actually found.
+    mShared->mFields.clear();
+    addGMLFields( false );
+    for ( const QgsField &field : fieldsBackup )
+      mShared->mFields.append( field );
   }
 }
 
@@ -721,7 +749,7 @@ void QgsWFSProvider::pushErrorSlot( const QString &errorMsg )
 
 void QgsWFSProvider::featureReceivedAnalyzeOneFeature( QVector<QgsFeatureUniqueIdPair> list )
 {
-  if ( list.size() != 0 )
+  if ( list.size() != 0 && mShared->mWKBType == QgsWkbTypes::Unknown )
   {
     QgsFeature feat = list[0].first;
     QgsGeometry geometry = feat.geometry();
@@ -780,6 +808,14 @@ void QgsWFSProvider::featureReceivedAnalyzeOneFeature( QVector<QgsFeatureUniqueI
       }
     }
   }
+  if ( list.size() != 0 )
+  {
+    QgsFeature feat = list[0].first;
+    feat.padAttributes( mShared->mFields.count() );
+    mSampleFeatureHasDescription = !feat.attribute( "description" ).isNull();
+    mSampleFeatureHasIdentifier = !feat.attribute( "identifier" ).isNull();
+    mSampleFeatureHasName = !feat.attribute( "name" ).isNull();
+  }
 }
 
 QString QgsWFSProvider::subsetString() const

src/providers/wfs/qgswfsprovider.h

@@ -139,6 +139,15 @@ class QgsWFSProvider final: public QgsVectorDataProvider
     //! Mutable data shared between provider and feature sources
     std::shared_ptr<QgsWFSSharedData> mShared;
 
+    //! Field set by featureReceivedAnalyzeOneFeature() if a "description" field is set in the sample feature
+    bool mSampleFeatureHasDescription = false;
+
+    //! Field set by featureReceivedAnalyzeOneFeature() if a "identifier" field is set in the sample feature
+    bool mSampleFeatureHasIdentifier = false;
+
+    //! Field set by featureReceivedAnalyzeOneFeature() if a "name" field is set in the sample feature
+    bool mSampleFeatureHasName = false;
+
     /**
      * Invalidates cache of shared object
     */