我正在用python+peewee+postgresql(没有django)做我的第一个telegram-bot项目。
我只是想知道，如何连接到我的数据库不是一次(在我的项目的代码开始)，但每次需要的时候。例如:用户点击按钮->连接打开->它将行添加到表
现在文件结构是这样的:
tgbot.py
# some lines with imports
updater = Updater(TELEGRAM_TOKEN)
dp = updater.dispatcher
dp = setup_dispatcher(dp)
# some lines with logging config
updater.start_polling()
updater.idle()
dispatcher.py
# some lines with imports
# some def for event handlers
# !!!!! here will be database connections (in functions for events)
def setup_dispatcher(dp):
db_conn = DBConnection() # Enter database connection
from dbmodels import db
db = db_conn.get_connection()
ToDo.create(...) # creating line in postgres-table
dp.add_handler(CommandHandler('start', start))
dp.add_handler(CommandHandler('location', ask_for_location))
dp.add_handler(MessageHandler(Filters.location, change_location))
dp.add_handler(CommandHandler('today', ask_for_today))
return dp
dbhelper.py
# some lines with imports
class DBConnection(Singleton):
def __init__(self): ... # initializing some variables like self.database, etc
def get_connection(self):
""" Creating PostgreSQL's database connection """
if self.connection is None:
try:
self.connection = PostgresqlDatabase(self.database, user=self.user, password=self.password, host=self.host, port=self.port)
self.curs = self.connection.cursor()
except (Exception, Error) as error:
print("PostgreSQL's connection error: n", error)
sys.exit(1)
return self.connection
def __del__(self):
""" Closing database connection """
if self.connection is not None:
self.curs.close()
self.connection.close()
print("PostgreSQL's connection closed.")
dbmodels.py
# some lines with imports
db = PostgresqlDatabase(None)
class Singleton:
""" Singleton realisation for database connection class in dbhelper.py """
_instance = None
def __new__(cls):
if cls._instance is None:
cls._instance = super().__new__(cls)
return cls._instance
class BaseModel(Model):
""" Basic class, used for tables-classes in models.py """
class Meta:
database = db
models.py
# some lines with imports
class User(BaseModel):
""" A model for client's table """
# initializing some fields
class Meta:
db_table = "clients"
...
class ToDo(BaseModel):
""" A model of to-do's table """
# initializing some fields
class Meta:
db_table = "to_do_s"
...
这些都是完全不必要的。peewee数据库对象已经是一个单例。当你想连接/关闭时，你只需要调用connect()和close()方法。
或者，您可以使用数据库实例作为上下文管理器，例如:
db = PostgresqlDatabase(...)
with db:
ToDo.create(...)