flask的简单使用
一.Flask中的CBV
from flask import Flask, render_template
from flask import views
app = Flask(__name__, template_folder='temp') # type:Flask
app.config['DEBUG'] = True
class LoginView(views.MethodView):
def get(self):
return render_template('login.html')
def post(self):
return '登录成功'
app.add_url_rule('/login', endpoint=None, view_func=LoginView.as_view('login'))
# 路由地址 指定endpoint为none as_view中的login为endpoint
if __name__ == '__main__':
app.run()
二. Flask 中的闪现(flash)
from flask import flash
flash('666', 'hu')
get_flashed_messages('hu') # 结果[('hu','666')]
get_flashed_messages(category_filter='hu')
flash('666')
get_flashed_messages() # 结果['666']
三. Flask-Session
from flask_session import Session
from flask import session
app.config["SESSION_TYPE"] = "redis"
app.config["SESSION_REDIS"] = Redis("127.0.0.1",6379,db=7)
Session(app)
session["user"] = "123"
session.get("user")
flask中的session存放在浏览器中的cookie中
四.Flask中的WTForms
class ResForm(Form):
username = simple.StringField(
label='用户名',
validators=[
validators.DataRequired(message='用户名不能为空'),
validators.Length(min=4, message='用户名不能低于五位数')
]
)
password = simple.PasswordField(
label='密码',
validators=[
validators.DataRequired(message='密码不能为空'),
validators.Length(min=4,message='密码不能低于五位数')
]
)
re_password = simple.PasswordField(
label='确认密码',
validators=[
validators.DataRequired(message='密码不能为空'),
validators.Length(min=4,message='密码不能低于五位数'),
validators.EqualTo('password', message='密码不一致')
]
)
email = simple.StringField( label='邮箱',
validators=[
validators.Email(message='格式不正确'),
])
sex = core.SelectField(
label='性别',
coerce=int,
choices=((1, '男'),
(2, '女')
),
default=1
)
hobby = core.SelectMultipleField(
label='爱好',
coerce=int,
choices=((1, '小萝莉'),
(2, '御姐'),
(3, '淑女'),
(4, '熟女'),
),
default=(1, 2 )
)
五.DBUtils 数据库连接池
from DBUtils.PooledDB import PooledDB
import pymysql
class MySQLhelper(object):
def __init__(self, host, port, dbuser, password, database):
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=int(port),
user=dbuser,
password=password,
database=database,
charset='utf8'
)
def create_conn_cursor(self):
conn = self.pool.connection()
cursor = conn.cursor(pymysql.cursors.DictCursor)
return conn,cursor
def fetch_all(self, sql, args):
conn,cursor = self.create_conn_cursor()
cursor.execute(sql,args)
result = cursor.fetchall()
cursor.close()
conn.close()
return result
def insert_one(self,sql,args):
conn,cursor = self.create_conn_cursor()
res = cursor.execute(sql,args)
conn.commit()
conn.close()
return res
def update(self,sql,args):
conn,cursor = self.create_conn_cursor()
res = cursor.execute(sql,args)
conn.commit()
print(res)
conn.close()
return res
sqlhelper = MySQLhelper("127.0.0.1", 3306, "root", "", "db7")
# res = sqlhelper.fetch_all("select * from userinfo where id=%s",(5,))
# print(res)
# res = sqlhelper.insert_one("insert into userinfo VALUES (%s,%s,%s)",(7,"jinwangba","66666"))
# print(res)
# sqlhelper.update("update user SET name=%s WHERE id=%s",("yinwangba",1))
六.Flask请求上下文流程
https://www.processon.com/view/5ae87bcde4b019d3a91b8047 request请求上下文流程
