一.特殊装饰器(中间件)
1.before_request
在请求进入视图函数之前
@app.before_request
def look():
2. after_request
在结束视图函数之后,响应返回客户端之前
@app.after_request
def af1(res)
from flask import Flask, request, session, redirect app = Flask(__name__)
app.secret_key = "#$%^&*(" @app.before_request # 在请求 之前
def look():
print("be1")
if request.path == "/login":
return None
if session.get("username"):
return None
else:
return redirect("/login")
# print(request.method)
# return "我是before 我不让你走" @app.before_request # 在请求 之前
def be2():
print("be2") @app.before_request # 在请求 之前
def be3():
print("be3") @app.route("/")
def index():
print("index page")
return "index page" @app.route("/login")
def login():
print("正在登陆......")
session["username"] = "username"
return "login" @app.after_request
def af1(vf_ret):
# vf_ret.response[]=b'2000000 OK!'
print("af1")
return vf_ret @app.after_request
def af2(vf_ret):
# vf_ret.response[]=b'2000000 OK!'
print("af2")
return vf_ret @app.after_request
def af3(vf_ret):
# vf_ret.response[]=b'2000000 OK!'
print("af3")
return vf_ret
if __name__ == '__main__':
app.run(debug=True)
打印的结果为:
请求顺序:
正常 : be1 - be2 - be3 - vf - af3 - af2 - af1
异常 : be1 - af3 - af2 - af1
3. errorhandler( )
重定义错误信息
@app.errorhandler()
def error404(errormessage):
实例:
from flask import Flask, request, session, redirect app = Flask(__name__) @app.route("/login")
def login():
print("正在登陆......")
return "login" @app.errorhandler(404) # 重定义404的错误
def error404(error_message):
print(error_message)
return f"你确定你要查看{request.path}这个页面吗?它已经走丢了,你快去找吧 "
# return redirect("http://baidu.com") if __name__ == '__main__':
app.run(debug=True)
二. Flask 中的 CBV
基本格式为:
from flask import Flask, request,views app = Flask(__name__) class Login(views.MethodView):
# methods=["POST","GET"]
# decorators = []
def get(self):
return "login" def post(self):
return "post_login" app.add_url_rule("/login",view_func=Login.as_view(name="login")) # endpoint = None 默认视图函数名as_view(name="login") name="login" if __name__ == '__main__':
app.run(debug=True)
三. windows 下 redis的使用
1.下载安装
①
②
③启动服务端: redis-server
启动客户端: redis-cli
2.redis 模块的使用
①模块下载
②简单使用
from redis import Redis re = Redis(host="127.0.0.1",port=,db=) # db 的范围在 1~15 类似于15 个库
# 切换时 用 select 1 re.set("kkk","") print(re.get("kkk"))
四. 三方组件 之 Flask-session
# .不想将Session的信息存放在Cookie
# .将Session存放在Redis
# .Cookie中保存Session的ID
1.组件下载
2.简单使用
①直接进行初始化
from flask import Flask, request, session
from flask_session import Session
from redis import Redis # from setting import Set app = Flask(__name__)
#初始化
app.config["SESSION_TYPE"] = "redis"
app.config["SESSION_REDIS"] = Redis(host="127.0.0.1",port=,db=) Session(app) @app.route("/login")
def login():
session["user"] = "username"
return "OK" @app.route("/see")
def see():
return session.get("user","还没有session") if __name__ == '__main__':
app.run(debug=True) # app.wsgi_app
② 设置setting.py 初始化 进行导入
1.在setting.py中
from redis import Redis
class Set(object):
SESSION_TYPE = "redis"
SESSION_REDIS = Redis()
2.使用时导入
五. 三方组件 之 WTForms
①下载
②简单使用
在 .py 文件中
from flask import Flask,request,render_template app = Flask(__name__) from wtforms.fields import simple,core
from wtforms import Form
from wtforms import validators class RegForm(Form):
username = simple.StringField(
label="用户名",
validators=[
validators.DataRequired(message="数据不能为空"),
validators.Length(min=,max=,message="%(min)d数据长度问题%(max)d")
],
render_kw={"class":"my_class"},
id="my_username"
) password = simple.PasswordField(
label="密码",
validators=[
validators.DataRequired(message="数据不能为空"),
validators.Length(min=, max=, message="%(min)d数据长度问题%(max)d")
],
render_kw={"class": "my_class"},
id="my_pwd"
) repassword = simple.PasswordField(
label="确认密码",
validators=[
validators.EqualTo("password",message="密码不一致")
]
) email = simple.StringField(
label="电邮",
validators=[
validators.Email(message="邮箱格式有问题例如1@1.1")
]
) hobby = core.SelectMultipleField( # 多选
label="爱好",
choices=[
(,"小姐姐"),
(,"老阿姨"),
(,"小萝莉"),
(,"御姐"),
],
default=[,],
coerce = int
) gender = core.SelectField( # 单选
label="性别",
choices=[
(, "小姐姐"),
(, "小哥哥"),
],
default=,
coerce=int
) sub = simple.SubmitField( # 可直接写在 .html 中,更方便
label="登录",
render_kw={"class":"red"}
) @app.route("/reg",methods=["POST","get"])
def reg():
if request.method == "GET":
rf = RegForm()
return render_template("reg.html",rf=rf)
else:
rf_data = RegForm(request.form)
if rf_data.validate():
print(rf_data.data)
return f"登陆成功{rf_data.data.get('username')}"
else:
return render_template("reg.html",rf=rf_data) if __name__ == '__main__':
app.run(debug=True)
在 .html 文件中
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
</head>
<body>
<form action="" method="post" novalidate>
{% for field in rf %}
<p>{{ field.label }}{{ field }}{{ field.errors. }}</p>
{% endfor %}
</form>
</body>
</html>