19.-哈希算法&注册登录

一、哈希算法

哈希:

给定明文-计算出一段定长的-不可逆的值

定长输出:不管明文输入多少，哈希都是定长的

不可逆:无法反向计算出对应的明文

雪崩效应:输入改变，输出必然变

md5:32位16进制

 

场景:

1.密码处理

2.文件完整性

 

用法: import hashlib

import hashlib m = hashlib.md5()  #1.生成哈希算法的计算对象

 

m.update(b'明文串') #2.传入要转换的字符串，必须声明bytes对象

 

m.hexdigest()   #3.输出对应的hash值，十六进制可视字符

 

m.digest() #3. 输出不可视的hash值 #如果要算一个新的值，需要生成新的update对象，不然会将前后的明文拼接起来输出哈希值

 

 

 

 

二、登录交互流程图

 

三、models/视图简单实现

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class User(models.Model):     username = models.CharField('用户名', max_length=30, unique=True)     password = models.CharField('密码', max_length=32)     create_time = models.DateTimeField('创建时间', auto_now_add=True)     updata_time = models.DateTimeField('更新时间', auto_now=True)       def __str__(self):         return f'username:{self.username}'

　　

def register_view(request):
    if request.method == 'GET':
        return render(request, 'user/register.html')
    if request.method == 'POST':
        username = request.POST.get('username')
        password = request.POST.get('password')
        password_verify = request.POST.get('password_verify')
        # 判断两次密码是否一致
        if password != password_verify:
            return HttpResponse('两次输入密码不一致')
        # 当前用户名是否可用
        old_users = User.objects.filter(username=username)
        if old_users:
            return HttpResponse('当前用户名已经注册')
        # 哈希算法转换密码
        hash = hashlib.md5()
        hash.update(password.encode())
        hash_pwd = hash.hexdigest()

        # 插入数据
        try:
            user = User.objects.create(username=username, password=hash_pwd)
        except Exception as e:
            # 有可能报错，重复插入 唯一索引注意并发写入问题,所以有唯一索引一定要try一下
            logger.error(f'register  create user info {e}')
            return HttpResponse('当前用户名已经注册')

        # 存储 session / 免登录一天
        request.session['username'] = username
        request.session['uid'] = user.id
        # 修改session 有效期为1天
        return HttpResponseRedirect('/index')


def login_view(request):
    if request.method == 'GET':
        # 检查登录状态，如果登录了，显示已登录
        if request.session.get('username') and request.session.get('uid'):
            return HttpResponseRedirect('/index')

        # 检查cookie
        c_username = request.COOKIES.get('username')
        c_uid = request.COOKIES.get('uid')
        if c_username and c_uid:
            # 回写session
            request.session['username'] = c_username
            request.session['uid'] = c_uid
            return HttpResponseRedirect('/index')

        return render(request, 'user/login.html')
    if request.method == 'POST':
        # 处理数据
        username = request.POST.get('username')
        password = request.POST.get('password')
        # 比对用户名
        try:
            user = User.objects.get(username=username)
        except Exception as e:
            logger.error(f'longin user {e}')
            return HttpResponse(f'用户名或密码不正确')

        # 判断密码
        # 哈希算法转换密码
        hash = hashlib.md5()
        hash.update(password.encode())
        # 密码比对
        if hash.hexdigest() != user.password:
            return HttpResponse('用户名或密码错误')
        # 记录会话状态
        request.session['username'] = username
        request.session['uid'] = user.id
        # 判断用户是否选中了记住当前用户
        # -> cookies 存储username.id 3天
        resp = HttpResponseRedirect('/index')

        if 'remember' in request.POST:
            resp.set_cookie('username', username, 3600 * 24 * 3)
            resp.set_cookie('uid', user.id, 3600 * 24 * 3)

        return resp


def logout_viwe(request):
    if 'username' in request.session:
        del request.session['username']
    if 'uid' in request.session:
        del request.session['uid']
    resp = HttpResponseRedirect('/index')
    if 'username' in request.COOKIES:
        resp.delete_cookie('username')
    if 'uid' in request.COOKIES:
        resp.delete_cookie('uid')
    return resp