Flask 学习
flask 项目配置
Debug模式 Host、Port配置
from flask import Flask
app = Flask(__name__)@app.route('/')defhello_world():return'Hello World!'if __name__ =='__main__':
app.run()
在pycharm中，设置debug模式和port端口号
# 在非pycharm中，设置debug模式if __name__=='__main__':
app.run(debug=True)
# 在非pycharm中，设置host和postif __name__=='__main__':
app.run(debug=True,host='0.0.0.0',port=9000)# port必须是整数，不能设置为字符串
在app.config中添加配置
from flask import Flask
app = Flask(__name__)# cofig 配置项，配置项的名称必须大写
app.config['SECRET_KEY']='sknrek349Lx!@#'
# 使用python配置# 在文件夹中创建一个config.py文件# 文件内容的代码如：
TOKEN_KEY ="123456"
加载配置文件
from flask import Flask
import config
app = Flask(__name__)
app.config.from_object(config)print(app.config["TOKEN_KEY"])@app.route('/')defhello_world():return'Hello World!'if __name__ =='__main__':
app.run()
URL 和 视图
定义无参URL
@app.route('/profile')defprofile():return"这是个人中心"
定义有参URL
@app.route('/blog/<blog_id>')defblog_detail(blog_id):return f'您查找的博客ID为{blog_id}
指定参数类型
语法：<类型:参数名>
如：
@app.route(‘/blog/int:blog_id’)
def blog_detail(blog_id):
return f’您查找的博客ID为{blog_id}
@app.route('/blog/list/<any(python,flask,django):category>')defblog_list_with_category(category):returnf'您获取的博客分类为{category}'# any 备选值中的任一个
# URL中需要传递多个参数，则只要用斜杠（/）分隔开来即可。@app.route('/blog/list/<int:user_id>/<int:page>')defblog_list(user_id,page):returnf'您查找的用户是{user_id}，博客分页为{page}'
# url 拼接：http://127.0.0.1:9000/blog/list?user_id=8&page=9# request 是一个线程隔离的全局对象@app.route('/blog/list')defblog_list_query_str():
user_id = request.args.get('user_id')
page=request.args.get("page")returnf'您查找的用户是{user_id},博客分页为{page}'
HTTP请求方法
@app.route("/blog/add",methods=['POST'])defblog_add():return"使用POST方法添加博客"
@app.route('/blog/add/post/get',methods=['POST',"GET"])defblog_add_post_get():if request.method =='GET':return"使用GET方法添加博客"else:return"使用POST方法添加博客"
页面重定向
from flask import url_for, redirect
@app.route('/login')deflogin():return'login page'@app.route('/profile')defprofile():
name = request.args.get('name')ifnot name:# 如果没有name 说明没有登录成功，重定向到登录页面return redirect("/login")else:return name
构造URl
# 构造[email protected]('/blog<int:blog_id>')defblog_detail(blog_id):returnf'您查找的博客ID为{blog_id}'@app.route('/urlfor')defget_url_for():
url = url_for("blog_detail",blog_id=2,user='admin')return url
# 输出结果为：/blog2?user=admin
jinja2模版
模版的基本使用
渲染模版
在视图函数中使用render_template函数渲染index.html模版
from flask import render_template
# 模版的基本使用@app.route('/index')defidnex():return render_template('index.html')
渲染变量
# 渲染变量@app.route('/variable')defvariable():
hobby ="游戏"return render_template("variable.html",hobby=hobby)
# <!DOCTYPE html><html lang="en"><head><meta charset="UTF-8"><title>Title</title></head><body><h1>我的兴趣爱好是{{ hobby }}</h1></body></html>
传递字典类型，person和对象类型user
<!DOCTYPE html><html lang="en"><head><meta charset="UTF-8"><title>Title</title></head><body><h1>我的兴趣爱好是{{ hobby }}</h1><p>person的姓名是{{ person.name }},person的年龄是{{ person.age }}</p><p>user的姓名是{{ user.username }},user的邮箱是{{ user.email }}</p></body></html>
classUser:def__init__(self,username,email):
self.username = username
self.email = email
@app.route('/variable')defvariable():
hobby='游戏'
person ={"name":"张三","age":18}
user = User("李四","[email protected]")return render_template('variable.html',hobby=hobby,person=person,user=user)-----# 也可以用这种方式classUser:def__init__(self,username,email):
self.username = username
self.email = email
@app.route('/variable')defvariable():
hobby='游戏'
person ={"name":"张三","age":18}
user = User("李四","[email protected]")
context ={"hobby":hobby,"person":person,'user':user
}# return render_template('variable.html',hobby=hobby,person=person,user=user)return render_template('variable.html',**context)
过滤器和测试器
自定义过滤器
import datetime
# 获取当前时间
_now = datetime.datetime.now()# 自定义时间过滤器@app.template_filter("time_filter")deftime_filter(time):ifnotisinstance(time,datetime.datetime):return time
_period =(_now-time).total_seconds()if _period<60:return'刚刚'elif60<= _period<60*60:returnf'{int(_period/60)}分钟之前'elif60*60<= _period <86400:returnf'{int(_period/3660)}小时之前'elif86400<= _period <2592000:returnf'{int(_period /86400)}天之前'else:return time.strftime('%Y-%m-%d %H:%M')@app.route('/filter')deftime_filter():
timelist=['abcd',
_now,
_now-datetime.timedelta(minutes=5),
_now-datetime.timedelta(hours=10),
_now-datetime.timedelta(days=5),
_now-datetime.timedelta(days=150)]return render_template('timefilter.html',timelist=timelist)
<!DOCTYPE html><html lang="en"><head><meta charset="UTF-8"><title>智能显示时间</title>{%for time in timelist %}<ul><li><p>{{ time }}</p><p>{{ time|time_filter }}</p></li></ul>{% endfor %}</head><body></body></html>
Jinja2 内置过滤器
# 内置过滤器@app.route('/filter')deffilter():
context={'username':'Sleet','password':123456,'age':-18,'sex':'女','script':'<script>alert("hello");</script>',"hobbies":{'basketball':'great','football':"not bad",'table tennis':'great','tennis':'bad'},'introduction':'I am a hangsome boy,I like playing basketball.'}return render_template('filter.html',**context)
<!DOCTYPE html><html lang="en"><head><meta charset="UTF-8"><title>Title</title></head><body><p>{{ username }}</p><p>{{ password }}</p><p>{{ age|abs}}</p><p>{{ sex|default('男')}}</p>{#关闭自动转义#}{% autoescape off %}<p>{{ script }}</p>{% endautoescape %}<p>{{ script|safe }}</p><p>{{ hobbies|first }}</p><!--获取序列第一个元素-->{#返回元素的长度#}<p>{{ hobbies|first|length }}</p><p>{{ hobbies|last }}</p><p>{{ username|replace('Sleet','Snow')}}</p><!--替换字符串--><!--截取字符串--><p>{{ introduction|truncate(length=13,killwords=False)}}</p><p>{{ introduction|wordcount }}</p><p>{{"%s and %s"|format('Sleet',"Snow")}}</p><p>{{ hobbies|join(d=' and ')}}</p><p>{{ script|striptags }}</p></body></html>
测试器
控制语句
if判断语句
# if判断语句@app.route('/if')defif_statement():
age =18return render_template('if.html',age=age)-------------# 或# if判断语句@app.route('/if/<int:age>')defif_statement(age):# age =18return render_template('if.html',age=age)
<!DOCTYPE html><html lang="en"><head><meta charset="UTF-8"><title>if 语句</title></head><body>{%if age >18%}<div>已成年！</div>{%elif age <18%}<div>未成年！</div>{%else%}<div>刚成年！</div>{% endif %}</body></html>
for循环语句
# for循环语句@app.route('/for')deffor_statement():
books=[{"name":"三国演义","author":"罗贯中","price":100},{"name":"水浒传","author":"施耐庵","price":99},{"name":"红楼梦","author":"曹雪芹","price":101},{"name":"西游记","author":"吴承恩","price":102}]return render_template('for.html',books=books)
<!DOCTYPE html><html lang="en"><head><meta charset="UTF-8"><title>Title</title></head><body><table><thead><tr><th>书名</th><th>作者</th><th>价格</th></tr></thead><tbody>{%for book in books %}<tr><th>{{ book.name }}</th><th>{{ book.author }}</th><th>{{ book.price }}</th></tr>{%else%}<tr><td colspan="3" style="text-align: center">无数据</td></tr>{% endfor %}</tbody></table></body></html>
模版结构
宏和import语句
<!DOCTYPE html><html lang="en"><head><meta charset="UTF-8"><title>Title</title></head><body>{% macro input(name,value='',type='text')%}<inputtype="{{ type }}" value="{{ value|escape }}" name="{{ name }}">{% endmacro %}{% macro textarea(name,value='',rows=10,cols=40)%}<textarea name="{{ name }}"id="" cols="{{ cols }}" rows="{{ rows }}">{{ value|escape }}</textarea>{% endmacro %}</body></html>
<!DOCTYPE html><html lang="en"><head><meta charset="UTF-8"><title>Title</title></head><body>{%import'forms.html'as forms %}<dl><dt>Username</dt><dd>{{ forms.input('username')}}</dd><dt>Password</dt><dd>{{ forms.input('password',type='password')}}</dd><p>{{ forms.textares('comment')}}</p></dl></body></html>
模版继承
# base.html 父类模版<!DOCTYPE html><html lang="en"><head><meta charset="UTF-8"><link rel="stylesheet" href="base.css"><title>{% block title %}{% endblock %}</title>{% block head %}{% endblock %}</head><body><div id="body">{% block body %}{% endblock %}</div><div id="'footer">{% block footer %}©Copyright 2008 by <a href="http://domain.invalid">you</a>{% endblock %}</div></body></html>
# 继承base模版{% extends "base.html"%}{% block title %} 首页{% endblock %}{% block head %}<style type="text/css">.detail {
color: red;}</style>{% endblock %}{% block body %}<h1>这里是首页</h1><p class="detail">首页的内容</p>{% endblock %}
模版环境
Mysql数据库
flask_SQLAlchemy的基本使用
连接Mysql
# 连接数据库from flask_sqlalchemy import SQLAlchemy
from sqlalchemy import text
# 配置连接数据库
hostname ='192.168.3.5'
port =3306
USERNAME ='root'
PASSWORD ='root'
DATABASE ='flask'
app.config['SQLALCHEMY_DATABASE_URI']=f"mysql+pymysql://{USERNAME}:{PASSWORD}@{hostname}:{port}/{DATABASE}?charset=utf8mb4"
db = SQLAlchemy(app)with app.app_context():with db.engine.connect()as conn:
rs = conn.execute(text("select 1"))print(rs.fetchone())# 输出：<sqlalchemy.engine.base.Connection object at 0x10b13d910>
ORM模型
# 创建1个User模型classUser(db.Model):
__tablename__ ='user'id= db.Column(db.Integer,primary_key =True,autoincrement=True)
username = db.Column(db.String(100))
password = db.Column(db.String(100))
# 运行with app.app_context():
db.create_all()
CRUD操作
Create操作
# app中完整的代码from flask import Flask
from flask import request
from flask import url_for, redirect
from flask import render_template
# 连接数据库from flask_sqlalchemy import SQLAlchemy
from sqlalchemy import text
app = Flask(__name__)# 配置连接数据库
hostname ='192.168.3.5'
port =3306
USERNAME ='root'
PASSWORD ='root'
DATABASE ='student'
app.config['SQLALCHEMY_DATABASE_URI']=f"mysql+pymysql://{USERNAME}:{PASSWORD}@{hostname}:{port}/{DATABASE}?charset=utf8mb4"
db = SQLAlchemy(app)classUser(db.Model):
__tablename__ ='db_user01'id= db.Column(db.Integer,primary_key=True,autoincrement=True)
username = db.Column(db.String(100))
password = db.Column(db.String(100))with app.app_context():
db.create_all()# CRUD操作# 1 Create操作@app.route('/user/add/')defuser_add():
user1 = User(username="张三",password="111111")
user2 = User(username="李四",password="222222")
user3 = User(username="王五",password="333333")
db.session.add(user1)
db.session.add(user2)
db.session.add(user3)
db.session.commit()return'用户添加成功！'if __name__ =='__main__':
app.run()
Read操作
# 2 Read操作@app.route('/user/fetch/')defuser_fetch():# 获取User中的所有数据
users = User.query.all()for i in users:print(f"用户名为：{i.username},密码为：{i.password}")# 获取主键为1的User对象
user = User.query.get(1)print(user.username)# 获取第1条数据
user = User.query.first()print(user.username)return"数据提取成功"
# 过滤@app.route('/user/filter')defuser_filter():# filter
users = User.query.filter(User.username =='张三').all()print(users)# filter_by
users = User.query.filter_by(username ='张三').all()print(users)return'数据过滤成功！'
# order_by()使用方法@app.route('/user/filter_orderby')defuser_filter_orderby():# 正序排序
users = User.query.order_by("id")# users = User.query.order_by(User.id)for user in users:print(user.id)# 倒序排序
users = User.query.order_by(text("-id"))# users = User.query.order_by(User.id.desc())for user in users:print(user.id)return"数据过滤成功"
# groupby使用from sqlalchemy import func
# group_by()使用方法@app.route('/user/filter_groupby/')defuser_filter_groupby():
users = db.session.query(User.username,func.count(User.id)).group_by("username").all()print(users)return'数据过滤成功！'
update操作
# update操作@app.route('/user/update/')defuser_update():
user = User.query.get(1)
user.username ='张三_修改后'
db.session.commit()return'更新成功！'
# update操作@app.route('/user/update/')defuser_update():
user = User.query.get(1)
user.username ='张三_修改后'
db.session.commit()return'更新成功！'# 针对多条的数据更新@app.route('/user/update_filter/')defuser_update_filter():
User.query.filter(User.username.like("%张三%")).update({"password":User.password+"_被修改的"},synchronize_session=False)
db.session.commit()return'数据更新成功！'
delete操作
# delete操作@app.route('/user/delete/')defuser_delete():
user = User.query.get(1)
db.session.delete(user)
db.session.commit()return'数据删除成功！'
# delete操作@app.route('/user/delete/')defuser_delete():
user = User.query.get(1)
db.session.delete(user)
db.session.commit()return'数据删除成功！'# 删除多条@app.route('/user/delete_filter/')defuser_delete_filter():
User.query.filter(User.username.contains("张三")).delete(synchronize_session=False)
db.session.commit()return"数据删除成功！"
表关系
外键
# 外键classArticle(db.Model):
__tablename__="db_article"id= db.Column(db.Integer,primary_key=True,autoincrement=True)
title = db.Column(db.String(200),nullable=False)
content = db.Column(db.Text,nullable=False)
author_id = db.Column(db.Integer,db.ForeignKey("db_user01.id"))with app.app_context():
db.create_all()
一对多关系
建立关系
# 一对多建立关系# 这是单向关系classArticle_relationship1(db.Model):
__tablename__ ="db_article_relationship1"id= db.Column(db.Integer, primary_key=True, autoincrement=True)
title = db.Column(db.String(200), nullable=False)
content = db.Column(db.Text, nullable=False)
author_id = db.Column(db.Integer, db.ForeignKey("db_user01.id"))
author = db.relationship("User")
@app.route('/article_relationship1/add')defarticle_add_relationship1():
user = User.query.first()
article = Article_relationship1(title="aa",content="bb",author=user)
db.session.add(article)
db.session.commit()
article = Article_relationship1.query.filter_by(title='aa').first()print(article.author.username)return"查询成功"
建立双向关系
# 这是双向关系# 双向关系classUser_Article(db.Model):
__tablename__ ='db_user_article'id= db.Column(db.Integer,primary_key=True,autoincrement=True)
username = db.Column(db.String(100))
password = db.Column(db.String(100))
articles = db.relationship("Article_User",back_populates="author")classArticle_User(db.Model):
__tablename__ ="db_article_user"id= db.Column(db.Integer, primary_key=True, autoincrement=True)
title = db.Column(db.String(200), nullable=False)
content = db.Column(db.Text, nullable=False)
author_id = db.Column(db.Integer, db.ForeignKey("db_user_article.id"))
author = db.relationship("User_Article",back_populates="articles")with app.app_context():
db.create_all()
@app.route('/article_user/query')defarticle_user_query():
user = User_Article.query.first()for article in user.articles:print(article.title)return"双向关联查询成功"
简化关系定义
# 简化关系classUser_Article_jh(db.Model):
__tablename__ ='db_user_article_jh'id= db.Column(db.Integer,primary_key=True,autoincrement=True)
username = db.Column(db.String(100))
password = db.Column(db.String(100))classArticle_User_jh(db.Model):
__tablename__ ="db_article_user_jh"id= db.Column(db.Integer, primary_key=True, autoincrement=True)
title = db.Column(db.String(200), nullable=False)
content = db.Column(db.Text, nullable=False)
author_id = db.Column(db.Integer, db.ForeignKey("db_user_article_jh.id"))
author = db.relationship("User_Article_jh",backref="articles")
表单
表单验证
# 创建1个 register.html<!DOCTYPE html><html lang="en"><head><meta charset="UTF-8"><title>注册</title></head><body><form action="{{ url_for('register') }}" method="POST"><table><tr><td>用户名：</td><td><inputtype="text" name="username"></td></tr><tr><td>邮箱：</td><td><inputtype="email" name="email"></td></tr><tr><td>密码：</td><td><inputtype="password" name="password"></td></tr><tr><td>确认密码：</td><td><inputtype="password" name="confirm_password"></td></tr><tr><td></td><td><inputtype="submit" value="提交"></td></tr></table></form></body></html>
# 主程序from flask import Flask,request,render_template
app = Flask(__name__)@app.route('/register',methods=['GET','POST'])defregister():if request.method =='GET':return render_template('register.html')else:passif __name__ =="__main__":
app.run()
表单类编写
# 在根目录下，创建1个forms.pyfrom wtforms import Form,StringField
from wtforms.validators import length,email,equal_to
classRegisterForm(Form):
username = StringField(validators=[length(min=3,max=20,message="请输入正确长度的用户名！")])
email = StringField(validators=[email(message="请输入正确格式的邮箱")])
password = StringField(validators=[length(min=6,max=20,message="请输入正确的密码！")])
confirm_password = StringField(validators=equal_to("password",message="两次密码不一致！"))# 其中，wtforms包，pip install wtforms
视图函数中使用表单
from flask import Flask,request,render_template,redirect,flash,url_for
from forms import RegisterForm
# from email_validator import validate_email,EmailNotValidError
app = Flask(__name__)# 使用flash消息，必须在app三配置Secret_Key 或者，直接通过app.secret_key来设置秘钥。
app.secret_key ='linql_secret'# 设置一个唯一且保密的密钥@app.route('/register',methods=['GET','POST'])defregister():if request.method =='GET':return render_template('register.html')else:
form = RegisterForm(request.form)# 如果表单通过验证if form.validate():
email = form.email.data
username = form.username.data
password = form.password.data
# 下面数据可以保存到数据库里print("email",email)print("username",username)print("password",password)return"注册成功"else:for errors in form.errors.values():for error in errors:
flash(error)return redirect(url_for("register"))if __name__ =="__main__":
app.run()
<!DOCTYPE html><html lang="en"><head><meta charset="UTF-8"><title>注册</title></head><body><form action="{{ url_for('register') }}" method="POST"><table><tr><td>用户名：</td><td><inputtype="text" name="username"></td></tr><tr><td>邮箱：</td><td><inputtype="email" name="email"></td></tr><tr><td>密码：</td><td><inputtype="password" name="password"></td></tr><tr><td>确认密码：</td><td><inputtype="password" name="confirm_password"></td></tr><tr><td></td><td><inputtype="submit" value="提交"></td></tr></table><ul>{%for message in get_flashed_messages()%}<li>{{ message }}</li>{% endfor %}</ul></form></body></html>
自定义验证字段
from wtforms import Form,StringField,ValidationError
registed_email =['[email protected]','[email protected]']classRegisterForm(Form):defvalidate_email(self,field):
email = field.data
if email in registed_email:raise ValidationError("邮箱已被注册！")returnTrue
渲染表单
# 视图函数里from flask import Flask,request,render_template,redirect,flash,url_for
from forms import RegisterForm,LoginForm
@app.route('/login',methods=['GET','POST'])deflogin():# csrf(cross site request forgery,跨站请求伪造)
form = LoginForm(meta={"csrf":False})if form.validate_on_submit():
email=form.email.data
password = form.password.data
return redirect("/")return render_template('login.html',form=form)
<!DOCTYPE html><html lang="en"><head><meta charset="UTF-8"><title>Title</title></head><body><form action="" method="post"><table><tbody><tr><td>{{ form.email.label }}</td><td>{{ form.email }}</td></tr>{%for error in form.email.errors %}<tr><td></td><td>{{ error }}</td></tr>{% endfor %}<tr><td>{{ form.password.label }}</td><td>{{ form.password}}</td></tr>{%for error in form.password.errors %}<tr><td></td><td>{{ error }}</td></tr>{% endfor %}<tr><td>{{ form.remember.label }}</td><td>{{ form.remember()}}</td></tr><tr><td></td><td>{{ form.submit }}</td></tr></tbody></table></form></body></html>
CRSF攻击
Flask进阶
类视图
基本使用
from flask.views import View
classListView(View):defget_template_name(self):raise NotImplementedError()defrender_template(self,context):return render_template(self.get_template_name(),**context)defdispatch_request(self):
context ={'objects':self.get_objects()}return self.render_template(context)classUserView(ListView):defget_template_name(self):return'users.html'defget_objects(self):return Users.query.all()
方法限制
本文转载自: https://blog.csdn.net/qq_23938507/article/details/133825699
版权归原作者 Micheal_Dad 所有， 如有侵权，请联系我们删除。
版权归原作者 Micheal_Dad 所有， 如有侵权，请联系我们删除。