import pymysql
from DBUtils.PooledDB import PooledDB


class MysqlHelper(object):
    __slots__ = ('pool', )

    def __init__(self):
        self.pool = PooledDB(
            creator=pymysql,  # 使用链接数据库的模块
            maxconnections=6,  # 连接池允许的最大连接数，0和None表示不限制连接数
            mincached=2,  # 初始化时，链接池中至少创建的空闲的链接，0表示不创建
            maxcached=5,  # 链接池中最多闲置的链接，0和None不限制
            maxshared=3,  # 链接池中最多共享的链接数量，0和None表示全部共享。PS: 无用，因为pymysql和MySQLdb等模块的 threadsafety都为1，所有值无论设置为多少，_maxcached永远为0，所以永远是所有链接都共享。
            blocking=True,  # 连接池中如果没有可用连接后，是否阻塞等待。True，等待；False，不等待然后报错
            maxusage=None,  # 一个链接最多被重复使用的次数，None表示无限制
            setsession=[],  # 开始会话前执行的命令列表。如：["set datestyle to ...", "set time zone ..."]
            ping=0,  # ping MySQL服务端，检查是否服务可用。# 如：0 = None = never, 1 = default = whenever it is requested, 2 = when a cursor is created, 4 = when a query is executed, 7 = always
            host=host,
            port=3306,
            user=user,
            password=pwd,
            database=db,
            charset='utf8'
        )

    def connect(self):
        conn = self.pool.connection()
        cursor = conn.cursor(pymysql.cursors.DictCursor)
        return conn, cursor

    def connect_close(self, conn, cursor):
        cursor.close()
        conn.close()

    def op_mysql(self, sql, args):
        conn, cursor = self.connect()
        cursor.execute(sql, args)
        lastrowid = cursor.lastrowid
        conn.commit()
        self.connect_close(conn, cursor)
        return lastrowid

    def fetch_all(self, sql, args):
        conn, cursor = self.connect()
        cursor.execute(sql, args)
        data = cursor.fetchall()
        self.connect_close(conn, cursor)
        return data

    def fetch_one(self, sql, args):
        conn, cursor = self.connect()
        cursor.execute(sql, args)
        data = cursor.fetchone()
        self.connect_close(conn, cursor)
        return data


if __name__ == "__main__":
    mysql_helper = MysqlHelper()
    sql = "INSERT INTO sql_test(user_name,user_password) VALUES (%s,%s)"
    args = ('user', 'pwd')
    res = mysql_helper.op_mysql(sql, args)
    print(res)