登录之后更新导航

  1. 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
  2. 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
  3. 完成注销功能。
    1. 清除session
    2. 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=True,autoincrement=True)
          username = db.Column(db.String(20),nullable=False)
          password = db.Column(db.String(20), nullable=False)
          nickname = db.Column(db.String(20))
      
      db.create_all()
      # user=User(username='mis1234',password='111111')
      # db.session.add(user)
      # db.session.commit()
      
      
      @app.route('/')
      def base():
          return render_template("base.html")
      
      
      @app.route('/login/', methods=['GET', 'POST'])
      def login():
          if request.method == 'GET':
              return render_template("denglu.html")
          else:
              username = request.form.get('username')
              password = request.form.get('password')
              user = User.query.filter(User.username == username).first()
              if user:
                  if user.password == password:
                      session['user']=username
                      session.permanent=True
                      return redirect(url_for('base'))
                  else:
                      return '密码错误'
              else:
                  return '用户名不存在'
      
      @app.context_processor
      def mycontext():
          usern = session.get('username')
          if usern:
              return {'username':usern}
          else:
              return {}
      
      @app.route('/regist/', methods=['GET', 'POST'])
      def zhuce():
          if request.method == 'GET':
              return render_template("zhuce.html")
          else:
              username = request.form.get('username')
              password = request.form.get('password')
              nickname = request.form.get('nickname')
              user = User.query.filter(User.username == username).first()
              if user:
                  return '用户名已存在'
              else:
                  user = User(username=username, password=password, nickname=nickname)
                  db.session.add(user)  # 数据库,添加操作
                  db.session.commit()
                  return redirect(url_for('login'))
      @app.route('/logout/')
      def logout():
          session.clear()
          return redirect(url_for('base'))
      
      
      @app.route('/fabu/')
      def fabu():
          return  render_template('question.html')
      
      if __name__=='__main__':
          app.run(debug=True)
      <!DOCTYPE html>
      <html lang="en">
      <head>
          <meta charset="UTF-8">
          <title>{% block title %}{% endblock %}base</title>
          <link rel="stylesheet" href="../static/css/base.css" type="text/css">
          <script src="../static/js/base.js"></script>
       {% block head %}{% endblock %}
      </head>
      <body id="myBody">
      {% block main %}{% endblock %}
      
      
      <nav>
          <div class="qwe">
              <div class="qwe" style="padding-top:10px;">
                  <img id="myOnOff" onclick="myswitch()" src="http://www.runoob.com/images/pic_bulbon.gif" width="40px">
      
      
                   {% if username %}
          <li><a href="#">{{ username }}</a></li>
          <li style="float:left"><a href="{{ url_for('base') }}">注销</a></li>
          {% else %}
      
          <li style="float:left"><a  href="{{ url_for('login') }}">登陆</a></li>
          <li style="float:left"><a href="{{ url_for('zhuce') }}">注册</a></li>
          {% endif %}
                       <li style="float:left"><a href="{{ url_for('base')}}">首页</a></li>
                  <li style="float:left"><a href="{{ url_for('fabu')}}">发布</a></li>
      
              </div>
          </div>
      
          <br>
          <form method="get" action="#">
              <div class="qwe1">
                  <div class="qwe2" style="padding-left: 50px;">
                      <input type="text" name="title" required lay-verify="required"
                             placeholder="search"
                             autocomplete="off" class="layui-input">
                  </div>
                  <div class="qwe3" style="padding-left: 50px;">
                      <button type="submit" class="layui-btn layui-btn-primary">搜索</button>
                  </div>
              </div>
          </form>
          </nav>
      </body>
      </html><!DOCTYPE html>
      <html lang="en">
      <head>
          <meta charset="UTF-8">
          <title>{% block title %}{% endblock %}base</title>
          <link rel="stylesheet" href="../static/css/base.css" type="text/css">
          <script src="../static/js/base.js"></script>
       {% block head %}{% endblock %}
      </head>
      <body id="myBody">
      {% block main %}{% endblock %}
      
      
      <nav>
          <div class="qwe">
              <div class="qwe" style="padding-top:10px;">
                  <img id="myOnOff" onclick="myswitch()" src="http://www.runoob.com/images/pic_bulbon.gif" width="40px">
      
      
                   {% if username %}
          <li><a href="#">{{ username }}</a></li>
          <li style="float:left"><a href="{{ url_for('base') }}">注销</a></li>
          {% else %}
      
          <li style="float:left"><a  href="{{ url_for('login') }}">登陆</a></li>
          <li style="float:left"><a href="{{ url_for('zhuce') }}">注册</a></li>
          {% endif %}
                       <li style="float:left"><a href="{{ url_for('base')}}">首页</a></li>
                  <li style="float:left"><a href="{{ url_for('fabu')}}">发布</a></li>
      
              </div>
          </div>
      
          <br>
          <form method="get" action="#">
              <div class="qwe1">
                  <div class="qwe2" style="padding-left: 50px;">
                      <input type="text" name="title" required lay-verify="required"
                             placeholder="search"
                             autocomplete="off" class="layui-input">
                  </div>
                  <div class="qwe3" style="padding-left: 50px;">
                      <button type="submit" class="layui-btn layui-btn-primary">搜索</button>
                  </div>
              </div>
          </form>
          </nav>
      </body>
      </html>
原文地址:https://www.cnblogs.com/hxl316/p/7890397.html