upgrades

db.py

@@ -0,0 +1,45 @@
+"""MySQL connection helper (PyMySQL).
+
+Connection settings come from environment variables so nothing is hard-coded:
+
+    WIKI_DB_HOST      default 127.0.0.1
+    WIKI_DB_PORT      default 3306
+    WIKI_DB_USER      default root
+    WIKI_DB_PASSWORD  default "" (empty)
+    WIKI_DB_NAME      default wiki
+
+`connect()` selects the wiki database; `connect(select_db=False)` connects to the
+server without a database (used by migrate.py to CREATE DATABASE).
+"""
+
+from __future__ import annotations
+
+import os
+
+import pymysql
+from pymysql.cursors import DictCursor
+
+
+def _cfg() -> dict:
+    return {
+        "host": os.environ.get("WIKI_DB_HOST", "127.0.0.1"),
+        "port": int(os.environ.get("WIKI_DB_PORT", "3306")),
+        "user": os.environ.get("WIKI_DB_USER", "root"),
+        "password": os.environ.get("WIKI_DB_PASSWORD", ""),
+    }
+
+
+def db_name() -> str:
+    return os.environ.get("WIKI_DB_NAME", "wiki")
+
+
+def connect(select_db: bool = True) -> pymysql.connections.Connection:
+    kwargs = _cfg()
+    if select_db:
+        kwargs["database"] = db_name()
+    return pymysql.connect(
+        cursorclass=DictCursor,
+        autocommit=True,
+        charset="utf8mb4",
+        **kwargs,
+    )