登录之后更新导航

Posted 2020-10-15 018林彬

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用上下文处理器app_context_processor定义函数
1. 获取session中保存的值
2. 返回字典
在父模板中更新导航，插入登录状态判断代码。、
1. 注意用{% ... %}表示指令。
2. {{ }}表示变量

完成注销功能。

清除session

跳转

from flask import Flask, render_template, request, redirect, url_for, session
from flask_sqlalchemy import SQLAlchemy
import config
 
 
app = Flask(__name__)
app.config.from_object(config)
db = SQLAlchemy(app)
 
 
class User(db.Model):
    __tablename__ = ‘user‘
    id = db.Column(db.Integer, primary_key=TabError, autoincrement=True)
    username = db.Column(db.String(20), nullable=False)
    password = db.Column(db.String(20), nullable=False)
    nickname = db.Column(db.String(20), nullable=True)
 
 
# db.create_all()    #是否链接成功
 
 
# 数据添加
# user=User(username=‘ma‘,password=‘gg‘)
# db.session.add(user)
# db.session.commit()
#
#
# 数据更新
#
# user = User.query.filter(User.username==‘hh‘).first()
# user.password=‘gg‘
# db.session.commit()
#
#
# 数据查询
# user = User.query.filter(User.username==‘ma‘).first()
# print(user.username,user.password)
#
# 数据删除
# user = User.query.filter(User.username==‘ma‘).first()
# db.session.delete(user)
# db.session.commit()
 
 
# session会话连接
# filter()过滤器
# route制定路径和函数之间的关系
# def定义一个变量
 
@app.route(‘/‘)
def switch():
    return render_template(‘switch.html‘)
 
 
@app.route(‘/login/‘, methods=[‘GET‘, ‘POST‘])  # 跳转登陆,methods定义它有两种请求方式
def login():
    if request.method == ‘GET‘:
        return render_template(‘login.html‘)
    else:
        username = request.form.get(‘user‘)
        password = request.form.get(‘psw‘)
        user = User.query.filter(User.username == username).first()  # 判断用户名是否存在
        if user:
           if user.password == password:
               session[‘user‘]=username
               session.permanent = True
               return redirect(url_for(‘switch‘))
        else:
            return ‘用户名不存在‘
@app.context_processor
def mycontext():
    username=session.get(‘user‘)
    if username:
        return {‘username‘:username}
    else:
        return {}
 
@app.route(‘/register/‘, methods=[‘GET‘, ‘POST‘])  # 跳转注册,methods定义它有两种请求方式
def register():
    if request.method == ‘GET‘:
        return render_template(‘register.html‘)
    else:
 
        username = request.form.get(‘user‘)
        password = request.form.get(‘psw‘)
        nickname = request.form.get(‘nickname‘)
        user = User.query.filter(User.username == username).first()  # 判断用户名是否存在
        if user:
            return u‘该用户已存在‘
        else:
            user = User(username=username, password=password, nickname=nickname)
            db.session.add(user)
            db.session.commit()
            return redirect(url_for(‘login‘))
 
@app.route(‘/logout/‘)
def logout():
    session.clear()
    return render_template(‘switch.html‘)
 
@app.route(‘/wenda/‘)
def wenda():
    return render_template(‘wenda.html‘)
 
 
if __name__ == ‘__main__‘:
    app.run(debug=True)

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>
        首页
        {% block logintitle %}{% endblock %}
        {% block registertitle %}{% endblock %}
        {% block wendatitle %}{% endblock %}
    </title>
    <script>
        function mySwitch() {
            var oBody= document.getElementById("myBody");
            var oOnoff=document.getElementById("myOnOff");
            if(oOnoff.src.match("bulbon")){
                oOnoff.src="http://www.runoob.com/images/pic_bulboff.gif";
                oBody.style.background="black";
                oBody.style.color="yellow";
            }else{oOnoff.src="http://www.runoob.com/images/pic_bulbon.gif";
                oBody.style.background="lightcyan";
                oBody.style.color="black";
            }
        }
 
    </script>
   <link rel="stylesheet" type="text/css" href="../static/css/switch.css">
{% block loginhead %}{% endblock %}
{% block registerhead %}{% endblock %}
{% block wendahead %}{% endblock %}
 
</head>
<body id="myBody" style="background-color: lightcyan">
<nav>
<img src="{{ url_for(‘static‘,filename=‘image/gzsxy.png‘) }}" alt="" width="20px">
    <script>
    document.write(Date())
</script>
<br>
<p>{{ username }}context</p>
    <a href="{{ url_for(‘switch‘) }}">首页</a>
    {% if username %}
         <a href="#">{{ username }}</a>
         <a href="{{  url_for(‘logout‘)  }}">注销</a>
    {% else %}
        <a href="{{ url_for(‘login‘) }}">登录</a>
        <a href="{{ url_for(‘register‘) }}">注册</a>
    {% endif %}
 
 <a href="{{ url_for(‘wenda‘) }}">问答</a>
   <input type="text" placeholder="请输入关键字">
    <button type="submit">搜索</button>
   </nav>
{% block loginbody %}{% endblock %}
{% block registerbody %}{% endblock %}
{% block wendabody %}{% endblock %}
</body>
</html>

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