Hook.py: add get_db() as method of Hook class

Hook.py

@@ -1,4 +1,6 @@
+import sqlite3
 from abc import ABC, abstractmethod
+import os
 
 
 class Hook(ABC):  # See at Hook class as to observer in observer pattern
@@ -9,3 +11,19 @@ class Hook(ABC):  # See at Hook class as to observer in observer pattern
     @abstractmethod
     def update(self, operation_id: int) -> None:
         raise NotImplemented
+
+    @staticmethod
+    def get_db() -> sqlite3.Connection:
+        """
+        One connection per request is only one method to avoid sqlite3.DatabaseError: database disk image is malformed.
+        Connections in sqlite are extremely cheap (0.22151980000001004 secs for 1000 just connections and
+        0.24141229999999325 secs for 1000 connections for this getter, thanks timeit)
+        and don't require to be closed, especially in RO mode. So, why not?
+
+        :return:
+        """
+
+        db = sqlite3.connect(f'file:{os.environ["DB_PATH"]}?mode=ro', check_same_thread=False, uri=True)
+        db.row_factory = lambda c, r: dict(zip([col[0] for col in c.description], r))
+
+        return db