[ogr] Fallback to writing metadata as a QMD file for non-geopackage,

file based uris, and raise QgsNotSupportedException for non-file based uris
qgis · May 4, 2021 · 4cbec54 · 4cbec54
1 parent 667fe63
commit 4cbec54
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Showing 2 changed files with 114 additions and 24 deletions.
diff --git a/src/core/providers/ogr/qgsogrprovider.cpp b/src/core/providers/ogr/qgsogrprovider.cpp
@@ -7323,8 +7323,27 @@ bool QgsOgrProviderMetadata::saveLayerMetadata( const QString &uri, const QgsLay
 {
   const QVariantMap parts = decodeUri( uri );
   const QString path = parts.value( QStringLiteral( "path" ) ).toString();
-  if ( !path.isEmpty() )
+  if ( !path.isEmpty() && QFileInfo::exists( path ) )
   {
+    // export metadata to XML
+    QDomImplementation domImplementation;
+    QDomDocumentType documentType = domImplementation.createDocumentType( QStringLiteral( "qgis" ), QStringLiteral( "http://mrcc.com/qgis.dtd" ), QStringLiteral( "SYSTEM" ) );
+    QDomDocument document( documentType );
+
+    QDomElement rootNode = document.createElement( QStringLiteral( "qgis" ) );
+    rootNode.setAttribute( QStringLiteral( "version" ), Qgis::version() );
+    document.appendChild( rootNode );
+
+    if ( !metadata.writeMetadataXml( rootNode, document ) )
+    {
+      errorMessage = QObject::tr( "Error exporting metadata to XML" );
+      return false;
+    }
+
+    QString metadataXml;
+    QTextStream textStream( &metadataXml );
+    document.save( textStream, 2 );
+
     QFileInfo fi( path );
     if ( fi.suffix().compare( QLatin1String( "gpkg" ), Qt::CaseInsensitive ) == 0 )
     {
@@ -7353,25 +7372,6 @@ bool QgsOgrProviderMetadata::saveLayerMetadata( const QString &uri, const QgsLay
       // creating all the metadata tables to GDAL!
       if ( GDALSetMetadataItem( hLayer, "QGIS_VERSION", Qgis::version().toLocal8Bit().constData(), nullptr ) == CE_None )
       {
-        // export metadata to XML
-        QDomImplementation domImplementation;
-        QDomDocumentType documentType = domImplementation.createDocumentType( QStringLiteral( "qgis" ), QStringLiteral( "http://mrcc.com/qgis.dtd" ), QStringLiteral( "SYSTEM" ) );
-        QDomDocument document( documentType );
-
-        QDomElement rootNode = document.createElement( QStringLiteral( "qgis" ) );
-        rootNode.setAttribute( QStringLiteral( "version" ), Qgis::version() );
-        document.appendChild( rootNode );
-
-        if ( !metadata.writeMetadataXml( rootNode, document ) )
-        {
-          errorMessage = QObject::tr( "Error exporting metadata to XML" );
-          return false;
-        }
-
-        QString metadataXml;
-        QTextStream textStream( &metadataXml );
-        document.save( textStream, 2 );
-
         // so far so good, ready to throw the whole of the QGIS layer XML into the metadata table!
 
         // first we need to check if there's already a corresponding entry in gpkg_metadata -- if so, we need to update it.
@@ -7459,11 +7459,30 @@ bool QgsOgrProviderMetadata::saveLayerMetadata( const QString &uri, const QgsLay
         return false;
       }
     }
+    else
+    {
+      // file based, but not a geopackage -- store as .qmd sidecar file instead
+      // (possibly there's other formats outside of GPKG which also has some native means of storing metadata,
+      // which could be added for those formats before we resort to the sidecar approach!)
+      const QString qmdFileName = fi.dir().filePath( fi.completeBaseName() + QStringLiteral( ".qmd" ) );
+      QFile qmdFile( qmdFileName );
+      if ( qmdFile.open( QFile::WriteOnly | QFile::Truncate ) )
+      {
+        QTextStream fileStream( &qmdFile );
+        fileStream << metadataXml;
+        qmdFile.close();
+        return true;
+      }
+      else
+      {
+        errorMessage = tr( "ERROR: Failed to created default metadata file as %1. Check file permissions and retry." ).arg( qmdFileName );
+        return false;
+      }
+    }
   }
-  errorMessage = QObject::tr( "Storing metadata for the specified uri is not supported" );
-  return false;
-}
 
+  throw QgsNotSupportedException( QObject::tr( "Storing metadata for the specified uri is not supported" ) );
+}
 
 // ---------------------------------------------------------------------------
 

diff --git a/tests/src/python/test_provider_ogr.py b/tests/src/python/test_provider_ogr.py
@@ -19,6 +19,8 @@
 
 from osgeo import gdal, ogr  # NOQA
 from qgis.PyQt.QtCore import QVariant, QByteArray, QTemporaryDir
+from qgis.PyQt.QtXml import QDomDocument
+
 from qgis.core import (
     NULL,
     QgsAuthMethodConfig,
@@ -38,7 +40,9 @@
     QgsVectorLayer,
     QgsVectorFileWriter,
     QgsWkbTypes,
-    QgsNetworkAccessManager
+    QgsNetworkAccessManager,
+    QgsLayerMetadata,
+    QgsNotSupportedException
 )
 from qgis.testing import start_app, unittest
 from qgis.utils import spatialite_connect
@@ -1200,6 +1204,73 @@ def testShapefilesWithNoAttributes(self):
         vl = QgsVectorLayer(os.path.join(d.path(), 'writetest.shp'))
         self.assertEqual(vl.featureCount(), 1)
 
+    def testNonGeopackageSaveMetadata(self):
+        """
+        Save layer metadata for a file-based format which doesn't have native metadata support.
+        In this case we should resort to a sidecar file instead.
+        """
+        ml = QgsVectorLayer('Point?crs=epsg:4326&field=pk:integer&field=cnt:int8', 'test', 'memory')
+        self.assertTrue(ml.isValid())
+
+        d = QTemporaryDir()
+        options = QgsVectorFileWriter.SaveVectorOptions()
+        options.driverName = 'ESRI Shapefile'
+        options.layerName = 'metadatatest'
+        err, _ = QgsVectorFileWriter.writeAsVectorFormatV2(ml, os.path.join(d.path(), 'metadatatest.shp'),
+                                                           QgsCoordinateTransformContext(), options)
+        self.assertEqual(err, QgsVectorFileWriter.NoError)
+        self.assertTrue(os.path.isfile(os.path.join(d.path(), 'metadatatest.shp')))
+
+        uri = d.path() + '/metadatatest.shp'
+
+        # now save some metadata
+        metadata = QgsLayerMetadata()
+        metadata.setAbstract('my abstract')
+        metadata.setIdentifier('my identifier')
+        metadata.setLicenses(['l1', 'l2'])
+        ok, err = QgsProviderRegistry.instance().saveLayerMetadata('ogr', uri, metadata)
+        self.assertTrue(ok)
+
+        self.assertTrue(os.path.exists(os.path.join(d.path(), 'metadatatest.qmd')))
+        with open(os.path.join(d.path(), 'metadatatest.qmd'), 'rt') as f:
+            metadata_xml = ''.join(f.readlines())
+
+        metadata2 = QgsLayerMetadata()
+        doc = QDomDocument()
+        doc.setContent(metadata_xml)
+        self.assertTrue(metadata2.readMetadataXml(doc.documentElement()))
+        self.assertEqual(metadata2.abstract(), 'my abstract')
+        self.assertEqual(metadata2.identifier(), 'my identifier')
+        self.assertEqual(metadata2.licenses(), ['l1', 'l2'])
+
+        # try updating existing metadata -- file should be overwritten
+        metadata2.setAbstract('my abstract 2')
+        metadata2.setIdentifier('my identifier 2')
+        metadata2.setHistory(['h1', 'h2'])
+        ok, err = QgsProviderRegistry.instance().saveLayerMetadata('ogr', uri, metadata2)
+        self.assertTrue(ok)
+
+        with open(os.path.join(d.path(), 'metadatatest.qmd'), 'rt') as f:
+            metadata_xml = ''.join(f.readlines())
+
+        metadata3 = QgsLayerMetadata()
+        doc = QDomDocument()
+        doc.setContent(metadata_xml)
+        self.assertTrue(metadata3.readMetadataXml(doc.documentElement()))
+        self.assertEqual(metadata3.abstract(), 'my abstract 2')
+        self.assertEqual(metadata3.identifier(), 'my identifier 2')
+        self.assertEqual(metadata3.licenses(), ['l1', 'l2'])
+        self.assertEqual(metadata3.history(), ['h1', 'h2'])
+
+    def testSaveMetadataUnsupported(self):
+        """
+        Test saving metadata to an unsupported URI
+        """
+        metadata = QgsLayerMetadata()
+        # this should raise a QgsNotSupportedException, as we don't support writing metadata to a WFS uri
+        with self.assertRaises(QgsNotSupportedException):
+            QgsProviderRegistry.instance().saveLayerMetadata('ogr', 'WFS:http://www2.dmsolutions.ca/cgi-bin/mswfs_gmap', metadata)
+
     def testEmbeddedSymbolsKml(self):
         """
         Test retrieving embedded symbols from a KML file