More Like This in CKAN (DGU extension)

ckanext-dgu.diff

diff --git a/ckanext/dgu/plugin.py b/ckanext/dgu/plugin.py
index 1da26dc..ce1dfbf 100644
--- a/ckanext/dgu/plugin.py
+++ b/ckanext/dgu/plugin.py
@@ -13,6 +13,7 @@ from ckan.plugins import IMiddleware
 from ckan.plugins import IAuthFunctions
 from ckan.plugins import IPackageController
 from ckan.plugins import ISession
+from ckan.plugins import IActions
 from ckanext.dgu.middleware import AuthAPIMiddleware
 from ckanext.dgu.auth import dgu_group_update, dgu_group_create, \
                              dgu_package_update, dgu_extra_fields_editable, \
@@ -198,6 +199,7 @@ class SearchPlugin(SingletonPlugin):
     """
 
     implements(IPackageController)
+    implements(IActions)
 
     def read(self, entity):
         pass
@@ -342,3 +344,24 @@ class SearchPlugin(SingletonPlugin):
         regex = re.compile(r'open government licen[sc]e', re.IGNORECASE)
         return pkg_dict['license_id'] == 'uk-ogl' or \
                bool(regex.search(pkg_dict.get('extras_access_constraints', '')))
+
+    def get_actions(self):
+        """
+        Should return a dict, the keys being the name of the logic
+        function and the values being the functions themselves.
+        """
+        def related_datasets(context, data_dict):
+            '''
+            Returns a list of datasets related to the one specified.
+            '''
+            from ckanext.dgu.lib.more_like_this import MoreLikeThisPackageQuery
+
+            model = context['model']
+            user = context['user']
+            dataset_name_or_id = data_dict.get('id') or data_dict.get('name') or data_dict['name_or_id']
+
+            results = MoreLikeThisPackageQuery().run(dataset_name_or_id)
+            return results
+
+        return {'related_datasets': related_datasets}
+    

ckanext.dgu.lib.more_like_this.py

from pylons import config
import logging

from ckan.lib.search import make_connection
from ckan.lib.search.query import SearchQuery
from ckan.lib.helpers import json

log = logging.getLogger(__name__)

class MoreLikeThisPackageQuery(SearchQuery):
    def run(self, dataset_ref, limit=5):
        '''
        Searches for datasets like the given one

        @param dataset_ref - id or name for a dataset
        @param limit - max number of results
        @return - list of results, each one a dictionary containing
                  keys: name, id, title 

        May raise SearchQueryError or SearchError.
        '''
        from solr import SolrException

        query = {
            'rows': 1,
            'q': 'name:%s OR id:%s' % (dataset_ref, dataset_ref),
            'wt': 'json',
            'fq': 'site_id:"%s"' % config.get('ckan.site_id'),
            'fl': 'id, index_id',
            'mlt': 'true',
            'mlt.fl': 'name,title,tags,notes',
            'mlt.mindf': 1,
            'mlt.mintf': 1,
            'mlt.count': limit,
            }

        conn = make_connection()
        log.debug('More Like This query: %r' % query)
        try:
            solr_response = conn.raw_query(**query)
        except SolrException, e:
            raise SearchError('SOLR returned an error running query: %r Error: %r' %
                              (query, e.reason))
        try:
            data = json.loads(solr_response)
            import pdb; pdb.set_trace()
            response = data[u'moreLikeThis']
            self.results = response.get('docs', [])

        except Exception, e:

            log.exception(e)
            raise SearchError(e)
        finally:
            conn.close()

        return self.results