完成登录功能，用session记住用户名

Posted 2020-10-15 100彭楚殷

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登录功能完成：

js:设置return
html:设置
1. form
2. input
3. ```
onclick="return fnLogin()"
```
py:
1. @app.route设置methods
2. GET
3. POST
  1. 读取表单数据
  2. 查询数据库
    1. 用户名密码对：
      1. 记住用户名
      2. 跳转到首页
    2. 用户名密码不对：
      1. 提示相应错误。

session：

从`flask`中导入`session`
设置`SECRET_KEY`

操作字典一样操作`session`：增加用户名`session[‘username‘]=`username

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()

@app.route(‘/‘)
def vi():
    return render_template("base.html")
@app.route(‘/first‘)
def base():
    return render_template("base.html")

@app.route("/login",methods=["GET","POST"])
def login():
    if request.method == "GET":
      return render_template("login.html")
    else:
        usern = request.form.get("usern")
        passw = request.form.get("userp")
        user = User.query.filter(User.username==usern).first()
        if user:
            if user.password == passw:
                session["user"] = usern
                # session.permanent = True
                return redirect(url_for("base"))
            else:
                return "密码错误，请重新输入！"
        else:
            return "用户名不存在！"


@app.route("/regist",methods=["GET","POST"])
def regist():
    if request.method == "GET":
        return render_template("regist.html")
    else:
        usern1 = request.form.get("newn")
        passw1 = request.form.get("newp")
        user = User.query.filter(User.username==usern1).first()
        if user:
            return "用户名已存在！"
        else:
            user = User(username = usern1,password = passw1)
            db.session.add(user)
            db.session.commit()
            return redirect(url_for("login"))


if __name__ == ‘__main__‘:
    app.run(debug=True)

import os
SQLALCHEMY_DATABASE_URI = ‘mysql+pymysql://root:@127.0.0.1:3306/mis_db?charset=utf8‘
SQLALCHEMY_TRACK_MODIFICATIONS = False

SECRET_KEY = os.urandom(24)

{% extends ‘base.html‘ %}
{% block title %}
登录
{% endblock %}
{% block head %}
    <link href="{{ url_for("static",filename="css/vv.css") }}" rel="stylesheet" type="text/css">
    <script src="{{ url_for("static",filename="js/login.js") }}"></script>
{% endblock %}
{% block main %}
<body bgcolor="#778899" class="div4">
<div class="div1">
    <h2 class="title"></h2>
    <form action="{{ url_for("login") }}"method="post">
        <div class="normal-title">
            <a class="div2" href="login.html">登录</a>
            <b>|</b>
            <a  class="div2" href="regist.html">注册</a>
        </div>

    <div class="div3">
        用户：<input id="username" type="text" placeholder="请输入昵称" name="usern">
    </div>
    <div class="div3">
        密码：<input id="userpass" type="text" placeholder="请输入密码" name="userp">
    </div>
    <div id="error_box"><br></div>
     <div class="div3">
        <button onclick="return myLogin()">Login</button>
    </div>
    <div class="div2">ByYin</div>
    </form>
</div>
<br>
</body>
{% endblock %}
</html>

 function myLogin() {
     var uName = document.getElementById("username");
     var uError = document.getElementById("error_box");
     var uPass =document.getElementById("userpass");
     var isError = true;
     uError.innerHTML="<br>";
     if (uName.value.length < 6||uName.value.length > 20) {
         uError.innerHTML = "用户名为6位到20位！";
         isError = false;
         return isError;
     }
     else if ((uName.value.charCodeAt(0)) >= 48 && uName.value.charCodeAt(0) <= 57) {
         uError.innerHTML = "用户名首字母不能为数字";
         isError = false;
         return isError;
     }
     else for(var i=0;i<uName.value.length;i++){
         if((uName.value.charCodeAt(i)<48||uName.value.charCodeAt(i)>57)&&(uName.value.charCodeAt(i)<97||uName.value.charCodeAt(i)>122)){
             uError.innerHTML="用户名只能为字母或数字";
             isError = false;
             return isError;
         }
     }
     if (uPass.value.length<6||uPass.value.length>20){
         uError.innerHTML="密码为6-20位！";
         isError = false;
         return isError;
     }
     return isError;
 }

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完成登录功能，用session记住用户名