server: refactor + add type hinting

- Added type hinting (for now, 3.5-compatible)
- Split `db` namespace into `db` module and `model` namespace
- Changed elastic search to be created lazily for each operation
- Changed to class based approach in entity serialization to allow
  stronger typing
- Removed `required` argument from `context.get_*` family of functions;
  now it's implied if `default` argument is omitted
- Changed `unalias_dict` implementation to use less magic inputs

1 files changed, 7 insertions, 4 deletions

diff --git a/server/szurubooru/func/versions.py b/server/szurubooru/func/versions.py
index ee84407..459b025 100644
--- a/server/szurubooru/func/versions.py
+++ b/server/szurubooru/func/versions.py
@@ -1,8 +1,11 @@
-from szurubooru import errors
+from szurubooru import errors, rest, model
 
 
-def verify_version(entity, context, field_name='version'):
-    actual_version = context.get_param_as_int(field_name, required=True)
+def verify_version(
+        entity: model.Base,
+        context: rest.Context,
+        field_name: str='version') -> None:
+    actual_version = context.get_param_as_int(field_name)
     expected_version = entity.version
     if actual_version != expected_version:
         raise errors.IntegrityError(
@@ -10,5 +13,5 @@ def verify_version(entity, context, field_name='version'):
             'Please try again.')
 
 
-def bump_version(entity):
+def bump_version(entity: model.Base) -> None:
     entity.version = entity.version + 1