Added data download ability

backend/src/database/engine.py

@@ -0,0 +1,47 @@
+import json
+from urllib.parse import quote_plus
+
+import pydantic
+from sqlalchemy.engine import URL
+from sqlalchemy.ext.asyncio import AsyncEngine, create_async_engine
+
+import src.settings as settings
+
+engine: AsyncEngine
+
+
+def _custom_json_serializer(*args, **kwargs) -> str:
+    """
+    Encodes json in the same way that pydantic does.
+    """
+    return json.dumps(*args, default=pydantic.json.pydantic_encoder, **kwargs)
+
+
+# check if the engine must be created for the tests -> in memory sqlite
+if settings.TEST_MODE:
+    engine = create_async_engine(
+        "sqlite+aiosqlite://",
+        connect_args={"check_same_thread": False},
+        json_serializer=_custom_json_serializer,
+    )
+elif settings.DB_USE_SQLITE:
+    engine = create_async_engine(
+        URL.create(drivername="sqlite+aiosqlite", database=settings.DB_SQLITE_PATH),
+        connect_args={"check_same_thread": False},
+        json_serializer=_custom_json_serializer,
+    )
+else:
+    # use the postgresql database
+    _encoded_password = quote_plus(settings.DB_PASSWORD)
+    engine = create_async_engine(
+        URL.create(
+            drivername="postgresql+asyncpg",
+            username=settings.DB_USER,
+            password=_encoded_password,
+            host=settings.DB_HOST,
+            port=settings.DB_PORT,
+            database=settings.DB_NAME,
+            json_serializer=_custom_json_serializer,
+        ),
+        pool_pre_ping=True,
+    )