Refactor database connection to use pymssql; update session management and requirements

app/db/session.py

@@ -1,37 +1,37 @@
 # app/db/session.py
 import os
-import urllib.parse
 from sqlalchemy import create_engine
 from sqlalchemy.orm import sessionmaker
 from app.core.config import settings
 
+# Read connection settings from app configuration
 USER = settings.SQLSERVER_USER
 PWD = settings.SQLSERVER_PASSWORD
 HOST = settings.SQLSERVER_HOST
-PORT = settings.SQLSERVER_PORT or 31433   # <- default to 31433 if not set
+PORT = settings.SQLSERVER_PORT or 31433  # default port used by original project
 DB = settings.SQLSERVER_DB
 
-odbc_str = (
-    "DRIVER={ODBC Driver 18 for SQL Server};"
-    f"SERVER=tcp:{HOST},{PORT};"
-    f"DATABASE={DB};"
-    f"UID={USER};PWD={PWD};"
-    "Encrypt=yes;"
-    "TrustServerCertificate=yes;"   # diagnostic: OK for dev. remove/flip in prod.
-    "LoginTimeout=15;"
-)
-params = urllib.parse.quote_plus(odbc_str)
-DATABASE_URL = f"mssql+pyodbc:///?odbc_connect={params}"
-
-engine = create_engine(
-    DATABASE_URL,
-    pool_pre_ping=True,
-    echo=False,
-    connect_args={"timeout": 30},
-)
+
+def _build_pymssql_url(user: str, pwd: str, host: str, port: int, db: str) -> str:
+    """Build mssql+pymssql URL for SQLAlchemy."""
+    # pymssql connection string format: mssql+pymssql://<user>:<password>@<host>:<port>/<db>
+    # Note: passwords with special chars will be quoted by the URL constructor if needed.
+    return f"mssql+pymssql://{user}:{pwd}@{host}:{port}/{db}"
+
+
+if not all([USER, PWD, HOST, DB]):
+    raise RuntimeError("Missing required SQL Server connection settings (SQLSERVER_USER, SQLSERVER_PASSWORD, SQLSERVER_HOST, SQLSERVER_DB)")
+
+DATABASE_URL = _build_pymssql_url(USER, PWD, HOST, PORT, DB)
+
+try:
+    engine = create_engine(DATABASE_URL, pool_pre_ping=True, echo=False)
+except Exception as exc:
+    raise RuntimeError(f"Failed to create DB engine using pymssql: {exc}")
 
 SessionLocal = sessionmaker(autocommit=False, autoflush=False, bind=engine)
 
+
 def get_db():
     db = SessionLocal()
     try:

requirements.txt

@@ -2,6 +2,7 @@ fastapi
 uvicorn[standard]
 sqlalchemy
 pyodbc
+pymssql
 python-dotenv
 passlib[bcrypt]
 python-jose