ultimate_tictactoe_server/database_connection.py

122 lines
3.4 KiB
Python

import pymysql.cursors
import sys
def get_sql_time(datetime_object):
return datetime_object.strftime('%Y-%m-%d %H:%M:%S')
class SQLInjectionError(Exception):
def __init__(self):
# Call the base class constructor with the parameters it needs
super().__init__("Detected possible SQL injection attack!")
class DatabaseConnection(object):
"""
a singleton class for a global database connection
"""
instance = None
@staticmethod
def global_cursor():
assert DatabaseConnection.instance is not None
return DatabaseConnection.instance.get_cursor()
@staticmethod
def global_close():
assert DatabaseConnection.instance is not None
DatabaseConnection.instance.close()
@staticmethod
def global_commit():
assert DatabaseConnection.instance is not None
DatabaseConnection.instance.commit()
@staticmethod
def global_ping():
assert DatabaseConnection.instance is not None
DatabaseConnection.instance.connection.ping()
@staticmethod
def global_single_query(query, params=None):
DatabaseConnection.global_ping()
if ';' in query:
# Possible injection!
raise SQLInjectionError()
with DatabaseConnection.global_cursor() as c:
if params is None:
c.execute(query)
else:
c.execute(query, params)
return c.fetchall()
@staticmethod
def global_single_execution(sql_statement, params=None):
DatabaseConnection.global_ping()
if ';' in sql_statement:
# Possible injection detected!
raise SQLInjectionError()
with DatabaseConnection.global_cursor() as c:
if params is None:
c.execute(sql_statement)
else:
c.execute(sql_statement, params)
DatabaseConnection.global_commit()
def __init__(self,
host: str,
port: int,
user: str,
password: str,
db: str,
charset: str):
assert DatabaseConnection.instance is None
try:
self.connection = pymysql.connect(
host=host,
port=port,
user=user,
password=password,
db=db,
charset=charset,
cursorclass=pymysql.cursors.DictCursor)
DatabaseConnection.instance = self
except Exception as e:
sys.stderr.write("could not connect to database '" +
str(db) +
"' at " +
user +
"@" +
host +
":" +
str(port) +
"\nCheck the configuration in settings.py!\n")
raise Exception('could not connect to database')
def get_cursor(self):
return self.connection.cursor()
def close(self):
self.connection.close()
DatabaseConnection.instance = None
def commit(self):
self.connection.commit()
def test_connection():
import settings
DatabaseConnection(settings.db_host,
settings.db_port,
settings.db_user,
settings.db_pw,
settings.db_db,
settings.db_charset)