initial commit for GitHub

server/app/db/conn.py

@@ -0,0 +1,37 @@
+import os
+
+import mysql.connector
+from dotenv import load_dotenv
+
+
+class DBException(Exception):
+    pass
+
+
+def connect_db() -> mysql.connector.MySQLConnection:
+    """
+    Connects to the MySQL database using credentials from the .env file.
+    Returns a MySQLConnection object which can be used by the database query layer.
+
+    Credential values are validated and an exception is raised if any are missing.
+    """
+    load_dotenv()
+    host = os.getenv("DB_HOST")
+    user = os.getenv("DB_USER")
+    password = os.getenv("DB_PASSWORD")
+    database = os.getenv("DB_DATABASE")
+
+    if None in [host, user, password, database]:
+        raise DBException("Missing database credentials")
+
+    try:
+        return mysql.connector.connect(
+            host=host,
+            user=user,
+            password=password,
+            database=database,
+            auth_plugin="mysql_native_password",
+        )  # type: ignore
+
+    except mysql.connector.Error as err:
+        raise DBException("Could not connect to database") from err