基于 Pymsql 数据库连接池

helper.py

import pymysql

from settings import Config

def connect():
    conn = Config.POOL.connection()
    cursor = conn.cursor(cursor=pymysql.cursors.DictCursor)  # 以 字典的方式 显示
    return conn,cursor

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

def fetch_all(sql,args):
    conn,cursor = connect()

    cursor.execute(sql, args)
    record_list = cursor.fetchall()
    connect_close(conn,cursor)

    return record_list

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

    return result

def insert(sql, args):
    conn, cursor = connect()
    row = cursor.execute(sql, args)
    conn.commit()
    connect_close(conn, cursor)
    return row

settings.py

from DBUtils.PooledDB import PooledDB, SharedDBConnection
import pymysql
# 下载  DBUtils : pip3 install DBUtils
class Config(object):
    SALT = b"sdf1123df"
    SECRET_KEY = 'asdf123sdfsdfsdf'
    MAX_CONTENT_LENGTH = 1024 * 1024 * 7

    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='127.0.0.1',
        port=3306,
        user='root',
        password='',
        database='db2',
        charset='utf8'
    )

views

@account.route('/login/', methods=['GET', 'POST'])
def login():
    '''
    登陆
    :return:
    '''
    if request.method == 'GET':
        return render_template('login.html')

    username = request.form.get('user')
    password = request.form.get('pwd')

    pwd_md5 = md5(password)

    data = helper.fetch_one("select id,nickname from userinfo where user=%s and pwd =%s", (username, pwd_md5))

    if not data:
        return render_template('login.html', error='用户名密码错误')

    # session['user_info'] = data
    session['user_info'] = {'id': data['id'], 'nickname': data['nickname']}

    return redirect('/home/')