Prefer default language values for some Literal nodes

ckanext/dcat/profiles.py

@@ -164,9 +164,18 @@ def _object_value(self, subject, predicate):
 
         If found, the unicode representation is returned, else an empty string
         '''
+        default_lang = config.get('ckan.locale_default', 'en')
+        fallback = ''
         for o in self.g.objects(subject, predicate):
-            return unicode(o)
-        return ''
+            if isinstance(o, Literal):
+                if o.language and o.language == default_lang:
+                    return unicode(o)
+                # Use first object as fallback if no object with the default language is available
+                elif fallback == '':
+                    fallback = unicode(o)
+            else:
+                return unicode(o)
+        return fallback
 
     def _object_value_int(self, subject, predicate):
         '''

ckanext/dcat/tests/test_base_profile.py

@@ -3,6 +3,8 @@
 from rdflib import Graph, URIRef, Literal
 from rdflib.namespace import Namespace
 
+from ckantoolkit.tests import helpers
+
 from ckanext.dcat.profiles import RDFProfile, CleanedURIRef
 
 from ckanext.dcat.tests.test_base_parser import _default_graph
@@ -113,6 +115,60 @@ def test_object_value_not_found(self):
 
         eq_(value, '')
 
+    @helpers.change_config('ckan.locale_default', 'de')
+    def test_object_value_default_lang(self):
+        p = RDFProfile(_default_graph())
+
+        p.g.add((URIRef('http://example.org/datasets/1'),
+                 DCT.title, Literal('Test Datensatz 1', lang='de')))
+        p.g.add((URIRef('http://example.org/datasets/1'),
+                 DCT.title, Literal('Test Dataset 1 (EN)', lang='en')))
+
+        value = p._object_value(URIRef('http://example.org/datasets/1'),
+                                DCT.title)
+
+        assert isinstance(value, unicode)
+        eq_(value, 'Test Datensatz 1')
+
+    @helpers.change_config('ckan.locale_default', 'fr')
+    def test_object_value_default_lang_not_in_graph(self):
+        p = RDFProfile(_default_graph())
+
+        p.g.add((URIRef('http://example.org/datasets/1'),
+                 DCT.title, Literal('Test Datensatz 1', lang='de')))
+
+        value = p._object_value(URIRef('http://example.org/datasets/1'),
+                                DCT.title)
+
+        assert isinstance(value, unicode)
+        # FR is not in graph, so either node may be used
+        assert value.startswith('Test D')
+        assert value.endswith(' 1')
+
+    def test_object_value_default_lang_fallback(self):
+        p = RDFProfile(_default_graph())
+
+        p.g.add((URIRef('http://example.org/datasets/1'),
+                 DCT.title, Literal('Test Datensatz 1', lang='de')))
+        p.g.add((URIRef('http://example.org/datasets/1'),
+                 DCT.title, Literal('Test Dataset 1 (EN)', lang='en')))
+
+        value = p._object_value(URIRef('http://example.org/datasets/1'),
+                                DCT.title)
+
+        assert isinstance(value, unicode)
+        # without config parameter, EN is used as default
+        eq_(value, 'Test Dataset 1 (EN)')
+
+    def test_object_value_default_lang_missing_lang_param(self):
+        p = RDFProfile(_default_graph())
+
+        value = p._object_value(URIRef('http://example.org/datasets/1'),
+                                DCT.title)
+
+        assert isinstance(value, unicode)
+        eq_(value, 'Test Dataset 1')
+
     def test_object_int(self):
 
         p = RDFProfile(_default_graph())