Fix case-insensitive search for unicode characters in SQLite (#520)

bookmarks/signals.py

@@ -1,8 +1,31 @@
+from os import path
+
 from django.contrib.auth import user_logged_in
+from django.db.backends.signals import connection_created
 from django.dispatch import receiver
+
 from bookmarks.services import tasks
 
+icu_extension_path = './libicu.so'
+icu_extension_exists = path.exists(icu_extension_path)
+
 
 @receiver(user_logged_in)
 def user_logged_in(sender, request, user, **kwargs):
     tasks.schedule_bookmarks_without_snapshots(user)
+
+
+@receiver(connection_created)
+def extend_sqlite(connection=None, **kwargs):
+    # Load ICU extension into Sqlite connection to support case-insensitive
+    # comparisons with unicode characters
+    if connection.vendor == 'sqlite' and icu_extension_exists:
+        connection.connection.enable_load_extension(True)
+        connection.connection.load_extension('./libicu')
+
+        with connection.cursor() as cursor:
+            # Load an ICU collation for case-insensitive ordering.
+            # The first param can be a specific locale, it seems that not
+            # providing one will use a default collation from the ICU project
+            # that works reasonably for multiple languages
+            cursor.execute("SELECT icu_load_collation('', 'ICU');")