作业26——完成登录功能，用session记住用户名

登录功能完成：

1. js:设置return

regist.js

function fnRegist() {
    var zcoUname = document.getElementById("zcuname")
    var zcoError = document.getElementById("zcerror_box")
    var zcoUword1 = document.getElementById("zcuword1")
    var zcoUword2 = document.getElementById("zcuword2")

    zcoError.innerHTML = "<br>"
    if (zcoUname.value.length < 6 || zcoUname.value.length > 12) {
        zcoError.innerHTML = "用户名为6到12位";
        return false;
    } else if ((zcoUname.value.charCodeAt(0) >= 48) && (zcoUname.value.charCodeAt(0) <= 57)) {
        zcoError.innerHTML = "用户名首位不能是数字";
        return false;
    } else for (var i = 0; i < zcoUname.value.length; i++) {
        if ((zcoUname.value.charCodeAt(i) < 48) || (zcoUname.value.charCodeAt(i) > 57) && (zcoUname.value.charCodeAt(i) < 97) || (zcoUname.value.charCodeAt(i) > 122)) {
            zcoError.innerHTML = "用户名只能是字母与数字";
            return false;
        }
    }
    if ((zcoUword1.value.length < 6) || (zcoUword1.value.length > 20)) {
        zcoError.innerHTML = "密码为6到20位";
        return false;
    }
    else if (zcoUword2.value.length == 0) {
        zcoError.innerHTML = "请再次输入密码";
        return false;
    }
    else if (zcoUword1.value != zcoUword2.value) {
        zcoError.innerHTML = "两次密码不一致"
        return false;
    }
    return true;
}

login.js

function fnLogin() {
    var oUname = document.getElementById("uname")
    var oError = document.getElementById("error_box")
    var oUword = document.getElementById("uword")

    oError.innerHTML = "<br>"
    if (oUname.value.length < 6 || oUname.value.length > 12) {
        oError.innerHTML = "用户名为6到12位";
        return false;
    } else if ((oUname.value.charCodeAt(0) >= 48) && (oUname.value.charCodeAt(0) <= 57)) {
        oError.innerHTML = "用户名首位不能是数字";
        return false;
    } else for (var i = 0; i < oUname.value.length; i++) {
        if ((oUname.value.charCodeAt(i) < 48) || (oUname.value.charCodeAt(i) > 57) && (oUname.value.charCodeAt(i) < 97) || (oUname.value.charCodeAt(i) > 122)) {
            oError.innerHTML = "用户名只能是字母与数字";
            return false;
        }
    }

    if ((oUword.value.length < 6) || (oUword.value.length > 20)) {
        oError.innerHTML = "密码为6到20位";
        return false;
    }
   return true;
}

1. html:设置
   1. form
   2. input

<form action="{{ url_for('regist') }}" method="post" onsubmit="return fnRegist()"> 
...... 

<div class="zcinput_box">
    <input type="submit" value="立即注册"></input>
</div>

</form>

1. 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。

@app.route('/login/', methods=['GET', 'POST'])
def login():
    if request.method=='GET':
        return render_template('login.html')
    else:
        usern = request.form.get('username')
        passw = request.form.get('password')
        user = User.query.filter(User.username == usern,User.password==passw).first()
    if user:
        session['user']=usern
        session.permanent=True
        return redirect(url_for('index'))

    else:
        return u'用户名不存在/密码错误'



@app.route('/regist/', methods=['GET', 'POST'])
def regist():
    if request.method == 'GET':
        return render_template('regist.html')
    else:
        # 获取form中的数据，判断用户名是否存在，存到数据库中
        username = request.form.get('username')
        nickname = request.form.get('nickname')
        password = request.form.get('password')
        user = User.query.filter(User.username == username).first()
        # 重定向到登录页
        if user:
            return u'用户名已存在'
        else:
            user = User(username=username, nickname=nickname, password=password)
            db.session.add(user)
            db.session.commit()
            return redirect(url_for('login'))

session：

1. 从`flask`中导入`session`

rom flask import Flask, render_template, request, redirect, url_for,session

1. 设置`SECRET_KEY`

import os

DEBUG=True
SECRET_KEY=os.urandom(24)

DIALEXT='mysql'
DRIVER='mysqldb'
USERNAME='root'
PASSWORD='ROOT'
HOST='@localhost'
PORT='3306'
DATABASE='meow'

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