search: add a singleton so apps can register their search engines (#25620)

combo/apps/search/__init__.py

@@ -17,6 +17,9 @@
 import django.apps
 from django.utils.translation import ugettext_lazy as _
 
+from .engines import engines
+
+
 class AppConfig(django.apps.AppConfig):
     name = 'combo.apps.search'
     verbose_name = _('Search')

combo/apps/search/engines.py

@@ -0,0 +1,35 @@
+# combo - content management system
+# Copyright (C) 2014-2018  Entr'ouvert
+#
+# This program is free software: you can redistribute it and/or modify it
+# under the terms of the GNU Affero General Public License as published
+# by the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Affero General Public License for more details.
+#
+# You should have received a copy of the GNU Affero General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+from django.conf import settings
+
+
+class Engines(object):
+    """Singleton object that serves as a registry of classes providing search
+    engines."""
+
+    def __init__(self):
+        self.engines = {}
+
+    def register(self, key, **options):
+        self.engines[key] = options
+
+    def get(self, key):
+        if key in settings.COMBO_SEARCH_SERVICES:
+            return settings.COMBO_SEARCH_SERVICES[key]
+        return self.engines.get(key)
+
+engines = Engines()  # singleton object

combo/apps/search/models.py

@@ -29,6 +29,8 @@ from combo.data.models import CellBase
 from combo.data.library import register_cell_class
 from combo.utils import get_templated_url
 
+from . import engines
+
 
 @register_cell_class
 class SearchCell(CellBase):
@@ -55,10 +57,7 @@ class SearchCell(CellBase):
     def search_services(self):
         services = []
         for service_slug in self._search_services.get('data') or []:
-            if service_slug == '_text':
-                service = {'url': reverse('api-search') + '?q=%(q)s', 'label': _('Page Contents')}
-            else:
-                service = settings.COMBO_SEARCH_SERVICES.get(service_slug)
+            service = engines.get(service_slug)
             if service and service.get('url'):
                 service['slug'] = service_slug
                 services.append(service)

combo/data/apps.py

@@ -15,7 +15,18 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 from django.apps import AppConfig
+from django.core.urlresolvers import reverse
+from django.utils.translation import ugettext_lazy as _
+
 
 class DataConfig(AppConfig):
     name = 'combo.data'
     verbose_name = 'data'
+
+    def ready(self):
+        # register built-in search engine for page contents
+        from combo.apps.search import engines
+        engines.register('_text',
+            url=reverse('api-search') + '?q=%(q)s',
+            label=_('Page Contents')
+        )

tests/test_search.py

@@ -40,7 +40,7 @@ class SearchServices(object):
         settings.COMBO_SEARCH_SERVICES = self.search_services
 
     def __exit__(self, *args, **kwargs):
-        delattr(settings, 'COMBO_SEARCH_SERVICES')
+        settings.COMBO_SEARCH_SERVICES = {}
 
 def test_search_cell(app):
     with SearchServices(SEARCH_SERVICES):