allow package_search to return specified fields

ckan/logic/action/get.py

@@ -1831,10 +1831,9 @@ def package_search(context, data_dict):
 
     fl
         The parameter that controls which fields are returned in the solr
-        query cannot be changed.  CKAN always returns the matched datasets as
-        dictionary objects.
-        if fl='id' or 'name', only this field in the dataset dictionary will
-        be returned.
+        query.
+        fl can be  None or a list of result fields, such as ['id', 'extras_custom_field'].
+        if fl = None, datasets are returned as a list of full dictionary.
     '''
     # sometimes context['schema'] is None
     schema = (context.get('schema') or
@@ -1878,9 +1877,11 @@ def package_search(context, data_dict):
             data_source = 'validated_data_dict'
         data_dict.pop('use_default_schema', None)
 
-        # return a list of package ids
-        if data_dict.get('fl') not in ('id', 'name'):
+        result_fl = data_dict.get('fl')
+        if not result_fl:
             data_dict['fl'] = 'id {0}'.format(data_source)
+        else:
+            data_dict['fl'] = ' '.join(result_fl)
 
         # Remove before these hit solr FIXME: whitelist instead
         include_private = asbool(data_dict.pop('include_private', False))
@@ -1907,9 +1908,12 @@ def package_search(context, data_dict):
         # Add them back so extensions can use them on after_search
         data_dict['extras'] = extras
 
-        if data_dict.get('fl') in ['id', 'name']:
+        if result_fl:
             for package in query.results:
-                results.append( {data_dict.get('fl'):package} )
+                if package.get('extras'):
+                    package.update(package['extras'] )
+                    package.pop('extras')
+                results.append(package)
         else:
             for package in query.results:
                 # get the package object