Django Cookie Session和自定义分页

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）

删除Cookie

def logout(request):
    rep = redirect("/login/")
    rep.delete_cookie("user")  # 删除用户浏览器上之前设置的usercookie值
    return rep

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")

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()

    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。

Session版登陆验证

from functools import wraps


def check_login(func):
    @wraps(func)
    def inner(request, *args, **kwargs):
        next_url = request.get_full_path()
        if request.session.get("user"):
            return func(request, *args, **kwargs)
        else:
            return redirect("/login/?next={}".format(next_url))
    return inner


def login(request):
    if request.method == "POST":
        user = request.POST.get("user")
        pwd = request.POST.get("pwd")

        if user == "alex" and pwd == "alex1234":
            # 设置session
            request.session["user"] = user
            # 获取跳到登陆页面之前的URL
            next_url = request.GET.get("next")
            # 如果有，就跳转回登陆之前的URL
            if next_url:
                return redirect(next_url)
            # 否则默认跳转到index页面
            else:
                return redirect("/index/")
    return render(request, "login.html")


@check_login
def logout(request):
    # 删除所有当前请求相关的session
    request.session.delete()
    return redirect("/login/")


@check_login
def index(request):
    current_user = request.session.get("user", None)
    return render(request, "index.html", {"user": current_user})

CBV中加装饰器相关

CBV实现的登录视图

class LoginView(View):

    def get(self, request):
        """
        处理GET请求
        """
        return render(request, 'login.html')

    def post(self, request):
        """
        处理POST请求 
        """
        user = request.POST.get('user')
        pwd = request.POST.get('pwd')
        if user == 'alex' and pwd == "alex1234":
            next_url = request.GET.get("next")
            # 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':'alex'}
            # }
            request.session['user'] = user
            if next_url:
                return redirect(next_url)
            else:
                return redirect('/index/')
        return render(request, 'login.html')

要在CBV视图中使用我们上面的check_login装饰器，有以下三种方式：

from django.utils.decorators import method_decorator

1. 加在CBV视图的get或post方法上

from django.utils.decorators import method_decorator


class HomeView(View):

    def dispatch(self, request, *args, **kwargs):
        return super(HomeView, self).dispatch(request, *args, **kwargs)

    def get(self, request):
        return render(request, "home.html")
    
    @method_decorator(check_login)
    def post(self, request):
        print("Home View POST method...")
        return redirect("/index/")

2. 加在dispatch方法上

from django.utils.decorators import method_decorator


class HomeView(View):

    @method_decorator(check_login)
    def dispatch(self, request, *args, **kwargs):
        return super(HomeView, self).dispatch(request, *args, **kwargs)

    def get(self, request):
        return render(request, "home.html")

    def post(self, request):
        print("Home View POST method...")
        return redirect("/index/")

因为CBV中首先执行的就是dispatch方法，所以这么写相当于给get和post方法都加上了登录校验。

3. 直接加在视图类上，但method_decorator必须传 name 关键字参数

如果get方法和post方法都需要登录校验的话就写两个装饰器。

from django.utils.decorators import method_decorator

@method_decorator(check_login, name="get")
@method_decorator(check_login, name="post")
class HomeView(View):

    def dispatch(self, request, *args, **kwargs):
        return super(HomeView, self).dispatch(request, *args, **kwargs)

    def get(self, request):
        return render(request, "home.html")

    def post(self, request):
        print("Home View POST method...")
        return redirect("/index/")

补充

CSRF Token相关装饰器在CBV只能加到dispatch方法上

备注：

• csrf_protect，为当前函数强制设置防跨站请求伪造功能，即便settings中没有设置全局中间件。
• csrf_exempt，取消当前函数防跨站请求伪造功能，即便settings中设置了全局中间件。

from django.views.decorators.csrf import csrf_exempt, csrf_protect


class HomeView(View):

    @method_decorator(csrf_exempt)
    def dispatch(self, request, *args, **kwargs):
        return super(HomeView, self).dispatch(request, *args, **kwargs)

    def get(self, request):
        return render(request, "home.html")

    def post(self, request):
        print("Home View POST method...")
        return redirect("/index/")

自定义分页

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})

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)

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

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})

<!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>