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  • Python学习(三十六)—— Cookie、Session和自定义分页

    一、Django中操作Cookie

    获取Cookie

    request.COOKIES['key']
    request.get_signed_cookie(key, default=RAISE_ERROR, salt='', max_age=None)

    参数:

    • default: 默认值
    • salt: 加密盐
    • max_age: 后台控制过期时间

    设置Cookie

    rep = HttpResponse(...)
    rep = render(request, ...)
    
    rep.set_cookie(key,value,...)
    rep.set_signed_cookie(key,value,salt='加密盐',...)

    参数:

    • key, 键
    • value='', 值
    • max_age=None, 超时时间
    • expires=None, 超时时间(IE requires expires, so set it if hasn't been already.)
    • path='/', Cookie生效的路径,/ 表示根路径,特殊的:根路径的cookie可以被任何url的页面访问
    • domain=None, Cookie生效的域名
    • secure=False, https传输
    • httponly=False 只能http协议传输,无法被JavaScript获取(不是绝对,底层抓包可以获取到也可以被覆盖)

    Cookie版登陆校验

    def check_login(func):
        @wraps(func)
        def inner(request, *args, **kwargs):
            next_url = request.get_full_path()
            if request.get_signed_cookie("login", salt="SSS", default=None) == "yes":
                # 已经登录的用户...
                return func(request, *args, **kwargs)
            else:
                # 没有登录的用户,跳转刚到登录页面
                return redirect("/login/?next={}".format(next_url))
        return inner
    
    
    def login(request):
        if request.method == "POST":
            username = request.POST.get("username")
            passwd = request.POST.get("password")
            if username == "xxx" and passwd == "dashabi":
                next_url = request.GET.get("next")
                if next_url and next_url != "/logout/":
                    response = redirect(next_url)
                else:
                    response = redirect("/class_list/")
                response.set_signed_cookie("login", "yes", salt="SSS")
                return response
        return render(request, "login.html")

    二、Session

    Django中默认支持Session,其内部提供了5种类型的Session供开发者使用:

    • 数据库(默认)
    • 缓存
    • 文件
    • 缓存+数据库
    • 加密cookie

    数据库Session

    SESSION_ENGINE = 'django.contrib.sessions.backends.db'   # 引擎(默认)

    缓存Session

    SESSION_ENGINE = 'django.contrib.sessions.backends.cache'  # 引擎
    SESSION_CACHE_ALIAS = 'default'                            # 使用的缓存别名(默认内存缓存,也可以是memcache),此处别名依赖缓存的设置

    文件Session

    SESSION_ENGINE = 'django.contrib.sessions.backends.file'    # 引擎
    SESSION_FILE_PATH = None                                    # 缓存文件路径,如果为None,则使用tempfile模块获取一个临时地址tempfile.gettempdir() 

    缓存+数据库

    SESSION_ENGINE = 'django.contrib.sessions.backends.cached_db'        # 引擎

    加密Cookie Session

    SESSION_ENGINE = 'django.contrib.sessions.backends.signed_cookies'   # 引擎

    其他公用设置项:

    SESSION_COOKIE_NAME = "sessionid"                       # Session的cookie保存在浏览器上时的key,即:sessionid=随机字符串(默认)
    SESSION_COOKIE_PATH = "/"                               # Session的cookie保存的路径(默认)
    SESSION_COOKIE_DOMAIN = None                             # Session的cookie保存的域名(默认)
    SESSION_COOKIE_SECURE = False                            # 是否Https传输cookie(默认)
    SESSION_COOKIE_HTTPONLY = True                           # 是否Session的cookie只支持http传输(默认)
    SESSION_COOKIE_AGE = 1209600                             # Session的cookie失效日期(2周)(默认)
    SESSION_EXPIRE_AT_BROWSER_CLOSE = False                  # 是否关闭浏览器使得Session过期(默认)
    SESSION_SAVE_EVERY_REQUEST = False                       # 是否每次请求都保存Session,默认修改之后才保存(默认)

    不管你怎么设置Session,使用方式都一样:

    def index(request):
        # 获取、设置、删除Session中数据
        request.session['k1']
        request.session.get('k1',None)
        request.session['k1'] = 123
        request.session.setdefault('k1',123) # 存在则不设置
        del request.session['k1']
    
        # 所有 键、值、键值对
        request.session.keys()
        request.session.values()
        request.session.items()
        request.session.iterkeys()
        request.session.itervalues()
        request.session.iteritems()
    
    
        # 用户session的随机字符串
        request.session.session_key
    
        # 将所有Session失效日期小于当前日期的数据删除
        request.session.clear_expired()
    
        # 检查 用户session的随机字符串 在数据库中是否
        request.session.exists("session_key")
    
        # 删除当前用户的所有Session数据
        request.session.delete("session_key")
    
        request.session.set_expiry(value)
            * 如果value是个整数,session会在些秒数后失效。
            * 如果value是个datatime或timedelta,session就会在这个时间后失效。
            * 如果value是0,用户关闭浏览器session就会失效。
            * 如果value是None,session会依赖全局session失效策略。

    课后练习:Session版登陆验证

    CBV中加装饰器相关

    from django.utils.decorators import method_decorator

    1. 加在get或post方法上

    class LoginView(View):
        
        def dispatch(self, request, *args, **kwargs):
            return super(LoginView,self).dispatch(request, *args, **kwargs)
    
        def get(self,request):
            return render(request,'login.html')
    
        @method_decorator(test)
        def post(self,request):
            user = request.POST.get('user')
            pwd = request.POST.get('pwd')
            if user == 'alex' and pwd == "alex3714":
                # 生成随机字符串
                # 写浏览器cookie: session_id: 随机字符串
                # 写到服务端session:
                # {
                #     "随机字符串": {'user_info':'alex}
                # }
                request.session['user_info'] = "alex"
                return redirect('/index/')
            return render(request, 'login.html')

    2. 加在dispatch方法上

    class LoginView(View):
    
        @method_decorator(test)
        def dispatch(self, request, *args, **kwargs):
            return super(LoginView, self).dispatch(request, *args, **kwargs)
    
    
        def get(self, request):
            return render(request, 'login.html')
    
    
        def post(self, request):
            user = request.POST.get('user')
            pwd = request.POST.get('pwd')
            if user == 'alex' and pwd == "alex3714":
                # 生成随机字符串
                # 写浏览器cookie: session_id: 随机字符串
                # 写到服务端session:
                # {
                #     "随机字符串": {'user_info':'alex}
                # }
                request.session['user_info'] = "alex"
                return redirect('/index/')
            return render(request, 'login.html')

    3. 加在类上

    @method_decorator(test,name='get')
    class LoginView(View):
        
        def dispatch(self, request, *args, **kwargs):
            return super(LoginView,self).dispatch(request, *args, **kwargs)
    
        def get(self,request):
            return render(request,'login.html')
    
        def post(self,request):
            user = request.POST.get('user')
            pwd = request.POST.get('pwd')
            if user == 'alex' and pwd == "alex3714":
                # 生成随机字符串
                # 写浏览器cookie: session_id: 随机字符串
                # 写到服务端session:
                # {
                #     "随机字符串": {'user_info':'alex}
                # }
                request.session['user_info'] = "alex"
                return redirect('/index/)
            return render(request, 'login.html')

    4. CSRF Token相关只能加到dispatch方法上

    from django.views.decorators.csrf import csrf_exempt, csrf_protect
    
    class LoginView(View):
        @method_decorator(csrf_exempt)
        def dispatch(self, request, *args, **kwargs):
            return super(LoginView,self).dispatch(request, *args, **kwargs)
    
        def get(self,request):
            return render(request,'login.html')
    
        def post(self,request):
            user = request.POST.get('user')
            pwd = request.POST.get('pwd')
            if user == 'alex' and pwd == "alex3714":
                # 生成随机字符串
                # 写浏览器cookie: session_id: 随机字符串
                # 写到服务端session:
                # {
                #     "随机字符串": {'user_info':'alex}
                # }
                request.session['user_info'] = "alex"
                return redirect('/index/')
            return render(request, 'login.html')

    三、自定义分页

    稳扎稳打版

    data = []
    
    for i in range(1, 302):
        tmp = {"id": i, "name": "alex-{}".format(i)}
        data.append(tmp)
    
    print(data)
    
    
    def user_list(request):
    
        # user_list = data[0:10]
        # user_list = data[10:20]
        try:
            current_page = int(request.GET.get("page"))
        except Exception as e:
            current_page = 1
    
        per_page = 10
    
        # 数据总条数
        total_count = len(data)
        # 总页码
        total_page, more = divmod(total_count, per_page)
        if more:
            total_page += 1
    
        # 页面最多显示多少个页码
        max_show = 11
        half_show = int((max_show-1)/2)
    
        if current_page <= half_show:
            show_start = 1
            show_end = max_show
        else:
            if current_page + half_show >= total_page:
                show_start = total_page - max_show
                show_end = total_page
            else:
                show_start = current_page - half_show
                show_end = current_page + half_show
    
        # 数据库中获取数据
        data_start = (current_page - 1) * per_page
        data_end = current_page * per_page
    
        user_list = data[data_start:data_end]
    
        # 生成页面上显示的页码
        page_html_list = []
        # 加首页
        first_li = '<li><a href="/user_list/?page=1">首页</a></li>'
        page_html_list.append(first_li)
        # 加上一页
        if current_page == 1:
            prev_li = '<li><a href="#">上一页</a></li>'
        else:
            prev_li = '<li><a href="/user_list/?page={}">上一页</a></li>'.format(current_page - 1)
        page_html_list.append(prev_li)
        for i in range(show_start, show_end+1):
            if i == current_page:
                li_tag = '<li class="active"><a href="/user_list/?page={0}">{0}</a></li>'.format(i)
            else:
                li_tag = '<li><a href="/user_list/?page={0}">{0}</a></li>'.format(i)
            page_html_list.append(li_tag)
    
        # 加下一页
        if current_page == total_page:
            next_li = '<li><a href="#">下一页</a></li>'
        else:
            next_li = '<li><a href="/user_list/?page={}">下一页</a></li>'.format(current_page+1)
        page_html_list.append(next_li)
    
        # 加尾页
        page_end_li = '<li><a href="/user_list/?page={}">尾页</a></li>'.format(total_page)
        page_html_list.append(page_end_li)
    
        page_html = "".join(page_html_list)
    
        return render(request, "user_list.html", {"user_list": user_list, "page_html": page_html})

    封装保存版

    class Pagination(object):
        def __init__(self, current_page, total_count, base_url, per_page=10, max_show=11):
            """
            :param current_page: 当前页
            :param total_count: 数据库中数据总数
            :param per_page: 每页显示多少条数据
            :param max_show: 最多显示多少页
            """
            try:
                current_page = int(current_page)
            except Exception as e:
                current_page = 1
    
            self.current_page = current_page
            self.total_count = total_count
            self.base_url = base_url
            self.per_page = per_page
            self.max_show = max_show
    
            # 总页码
            total_page, more = divmod(total_count, per_page)
            if more:
                total_page += 1
            
            half_show = int((max_show - 1) / 2)
            self.half_show = half_show
            self.total_page = total_page
    
        @property
        def start(self):
            return (self.current_page - 1) * self.per_page
    
        @property
        def end(self):
            return self.current_page * self.per_page
    
        def page_html(self):
    
            if self.current_page <= self.half_show:
                show_start = 1
                show_end = self.max_show
            else:
                if self.current_page + self.half_show >= self.total_page:
                    show_start = self.total_page - self.max_show
                    show_end = self.total_page
                else:
                    show_start = self.current_page - self.half_show
                    show_end = self.current_page + self.half_show
    
                    # 生成页面上显示的页码
            page_html_list = []
            # 加首页
            first_li = '<li><a href="{}?page=1">首页</a></li>'.format(self.base_url)
            page_html_list.append(first_li)
            # 加上一页
            if self.current_page == 1:
                prev_li = '<li><a href="#">上一页</a></li>'
            else:
                prev_li = '<li><a href="{0}?page={1}">上一页</a></li>'.format(self.base_url, self.current_page - 1)
            page_html_list.append(prev_li)
            for i in range(show_start, show_end + 1):
                if i == self.current_page:
                    li_tag = '<li class="active"><a href="{0}?page={1}">{1}</a></li>'.format(self.base_url, i)
                else:
                    li_tag = '<li><a href="{0}?page={1}">{1}</a></li>'.format(self.base_url, i)
                page_html_list.append(li_tag)
    
            # 加下一页
            if self.current_page == self.total_page:
                next_li = '<li><a href="#">下一页</a></li>'
            else:
                next_li = '<li><a href="{0}?page={1}">下一页</a></li>'.format(self.base_url, self.current_page + 1)
            page_html_list.append(next_li)
    
            # 加尾页
            page_end_li = '<li><a href="{0}?page={1}">尾页</a></li>'.format(self.base_url, self.total_page)
            page_html_list.append(page_end_li)
    
            return "".join(page_html_list)

    封装保存版使用指南

    def user_list(request):
        pager = Pagination(request.GET.get("page"), len(data), request.path_info)
        user_list = data[pager.start:pager.end]
        page_html = pager.page_html()
        return render(request, "user_list.html", {"user_list": user_list, "page_html": page_html})

    扩展:

    Django内置分页

    内置分页view部分

    from django.shortcuts import render
    from django.core.paginator import Paginator, EmptyPage, PageNotAnInteger
    
    L = []
    for i in range(999):
        L.append(i)
    
    def index(request):
        current_page = request.GET.get('p')
    
        paginator = Paginator(L, 10)
        # per_page: 每页显示条目数量
        # count:    数据总个数
        # num_pages:总页数
        # page_range:总页数的索引范围,如: (1,10),(1,200)
        # page:     page对象
        try:
            posts = paginator.page(current_page)
            # has_next              是否有下一页
            # next_page_number      下一页页码
            # has_previous          是否有上一页
            # previous_page_number  上一页页码
            # object_list           分页之后的数据列表
            # number                当前页
            # paginator             paginator对象
        except PageNotAnInteger:
            posts = paginator.page(1)
        except EmptyPage:
            posts = paginator.page(paginator.num_pages)
        return render(request, 'index.html', {'posts': posts})

    内置分页HTML部分

    <!DOCTYPE html>
    <html>
    <head lang="en">
        <meta charset="UTF-8">
        <title></title>
    </head>
    <body>
    <ul>
        {% for item in posts %}
            <li>{{ item }}</li>
        {% endfor %}
    </ul>
    
    <div class="pagination">
          <span class="step-links">
            {% if posts.has_previous %}
                <a href="?p={{ posts.previous_page_number }}">Previous</a>
            {% endif %}
              <span class="current">
                Page {{ posts.number }} of {{ posts.paginator.num_pages }}.
              </span>
              {% if posts.has_next %}
                  <a href="?p={{ posts.next_page_number }}">Next</a>
              {% endif %}
          </span>
    
    </div>
    </body>
    </html>
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  • 原文地址:https://www.cnblogs.com/Coufusion/p/8351464.html
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