Flask 学习
flask 项目配置
Debug模式 Host、Port配置
from flask import Flaskapp = Flask(__name__)@app.route('/')def hello_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 Flaskapp = 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 Flaskimport configapp = Flask(__name__)app.config.from_object(config)print(app.config["TOKEN_KEY"])@app.route('/')def hello_world(): return 'Hello World!'if __name__ == '__main__': app.run()
URL 和 视图
定义无参URL
@app.route('/profile')def profile(): return "这是个人中心"定义有参URL
@app.route('/blog/<blog_id>')def blog_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>')def blog_list_with_category(category): return f'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>')def blog_list(user_id,page): return f'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')def blog_list_query_str(): user_id = request.args.get('user_id') page=request.args.get("page") return f'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'])def blog_add(): return "使用POST方法添加博客"@app.route('/blog/add/post/get',methods=['POST',"GET"])def blog_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')def login(): return 'login page'@app.route('/profile')def profile(): name = request.args.get('name') if not 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URL@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('/urlfor')def get_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')def idnex(): return render_template('index.html')渲染变量
# 渲染变量@app.route('/variable')def variable(): 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>class User: def __init__(self,username,email): self.username = username self.email = email@app.route('/variable')def variable(): hobby='游戏' person = { "name":"张三", "age":18 } user = User("李四","XXXX@qq.com") return render_template('variable.html',hobby=hobby,person=person,user=user)-----# 也可以用这种方式class User: def __init__(self,username,email): self.username = username self.email = email@app.route('/variable')def variable(): hobby='游戏' person = { "name":"张三", "age":18 } user = User("李四","XXXX@qq.com") 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")def time_filter(time): if not isinstance(time,datetime.datetime): return time _period = (_now-time).total_seconds() if _period<60: return '刚刚' elif 60<= _period< 60*60: return f'{int(_period/60)}分钟之前' elif 60*60 <= _period < 86400: return f'{int(_period/3660)}小时之前' elif 86400 <= _period < 2592000: return f'{int(_period / 86400)}天之前' else: return time.strftime('%Y-%m-%d %H:%M')@app.route('/filter')def time_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')def filter(): 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')def if_statement(): age =18 return render_template('if.html',age=age)-------------# 或# if判断语句@app.route('/if/<int:age>')def if_statement(age): # age =18 return 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')def for_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') %} <input type="{{ 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 SQLAlchemyfrom sqlalchemy import text# 配置连接数据库hostname = '192.168.3.5'port = 3306USERNAME = '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class User(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 Flaskfrom flask import requestfrom flask import url_for, redirectfrom flask import render_template# 连接数据库from flask_sqlalchemy import SQLAlchemyfrom sqlalchemy import textapp = Flask(__name__)# 配置连接数据库hostname = '192.168.3.5'port = 3306USERNAME = 'root'PASSWORD = 'root'DATABASE = 'student'app.config['SQLALCHEMY_DATABASE_URI'] = f"mysql+pymysql://{USERNAME}:{PASSWORD}@{hostname}:{port}/{DATABASE}?charset=utf8mb4"db = SQLAlchemy(app)class User(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/')def user_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/')def user_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')def user_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')def user_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/')def user_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/')def user_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/')def user_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/')def user_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/')def user_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/')def user_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/')def user_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class Article(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class Article_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')def article_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class User_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")class Article_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')def article_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class User_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))class Article_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><input type="text" name="username"></td> </tr> <tr> <td>邮箱：</td> <td><input type="email" name="email"></td> </tr> <tr> <td>密码：</td> <td><input type="password" name="password"></td> </tr> <tr> <td>确认密码：</td> <td><input type="password" name="confirm_password"></td> </tr> <tr> <td></td> <td><input type="submit" value="提交"></td> </tr> </table></form></body></html># 主程序from flask import Flask,request,render_templateapp = Flask(__name__)@app.route('/register',methods=['GET','POST'])def register(): 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,StringFieldfrom wtforms.validators import length,email,equal_toclass RegisterForm(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_forfrom forms import RegisterForm# from email_validator import validate_email,EmailNotValidErrorapp = 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'])def register(): 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><input type="text" name="username"></td> </tr> <tr> <td>邮箱：</td> <td><input type="email" name="email"></td> </tr> <tr> <td>密码：</td> <td><input type="password" name="password"></td> </tr> <tr> <td>确认密码：</td> <td><input type="password" name="confirm_password"></td> </tr> <tr> <td></td> <td><input type="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,ValidationErrorregisted_email = ['aa@example.com','bb@example.com']class RegisterForm(Form): def validate_email(self,field): email = field.data if email in registed_email: raise ValidationError("邮箱已被注册！") return True渲染表单
# 视图函数里from flask import Flask,request,render_template,redirect,flash,url_forfrom forms import RegisterForm,LoginForm@app.route('/login',methods=['GET','POST'])def login(): # 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 Viewclass ListView(View): def get_template_name(self): raise NotImplementedError() def render_template(self,context): return render_template(self.get_template_name(),**context) def dispatch_request(self): context = {'objects':self.get_objects()} return self.render_template(context) class UserView(ListView): def get_template_name(self): return 'users.html' def get_objects(self): return Users.query.all()
