Cookie、Session和自定义分页与django内置分页

为什么使用Cookie：因为HTTP请求是没有状态的，每一次请求都是独立的。

什么是Cookie：Cookie就是保存在浏览器上的键值对，服务端控制着响应，在响应里添加一个键值对，让浏览器在本地保存，下一次请求的时候，自动携带这个键值对，是在浏览器端设置的，浏览器端也可以禁用Cookie。

Cookie的设置，以及使用装饰器验证浏览器的登录状态

from django.shortcuts import render,HttpResponse,redirect

# Create your views here.
def login(request):
    if request.method == "POST":
        name = request.POST.get("name")
        pwd = request.POST.get("pwd")
        if name == 'alex' and  pwd == '123123':
            next = request.GET.get('next')
            print(next)
            if next:
                res = redirect(next)
                res.set_signed_cookie("is_login","1",salt="s10nb"，max_age=10)
                return res
            res =  redirect('/app01/home/')
            res.set_signed_cookie("is_login","1",salt="s10nb" ,max_age=10)
            return res
    return render(request, 'app01/login.html')
def  home(request):
    res = request.get_signed_cookie("is_login",default="0",salt="s10nb")
    if res == '1':
        return render(request, 'app01/home.html')
    else :
        return  redirect('/app01/login/')

def timmer(func):
    def wrapper(request):
        res = request.get_signed_cookie("is_login",default="0",salt="s10nb")
        if res == '1':
           ret = func(request)
           return ret
        else :
            next_url = request.path_info
            print(next_url)
            return  redirect('/app01/login/?next={}'.format(next_url))
    return wrapper
@timmer
def index(request):
    return render(request, 'app01/index.html')

 默认关闭浏览器，Cookie值就失效，可以设置时长max_age=7*24*60*60(七天失效)

注销登录

def logout(request):
    rep = redict("/app01/login/")
    rep.delete_cookie('is_login')
    return rep

 Session

Session是保存在浏览器上的键值对，必须依赖Session，服务端生成的Cookie返回到浏览器，跟Cookie匹配的Session保存在服务器端，下次再登录时，根据Cookie获取Seeion值，存储的数据多，较为安全。

设置Session

 request.session['is_login']='1'

 获取Session值

首先获取Cookie的随机字符串，根据字符串的值去数据库取Seeion的数据，解密，把Session值反序列化成字典，然后在字典里可以根据key取值。

from django.shortcuts import render,HttpResponse,redirect

# Create your views here.
def login(request):
    if request.method == "POST":
        name = request.POST.get("name")
        pwd = request.POST.get("pwd")
        if name == 'alex' and  pwd == '123123':
            next = request.GET.get('next')
            print(next)
            if next:
                res = redirect(next)
                request.session['is_login']='1'
                return res
            res =  redirect('/app02/home/')
            request.session['is_login']='1'
            return res
    return render(request, 'app02/login.html')
def  home(request):
    res = request.session.get('is_login')
    if res == '1':
        return render(request, 'app02/home.html')
    else :
        return  redirect('/app02/login/')

def timmer(func):
    def wrapper(request):
        res = request.session.get('is_login')
        if res == '1':
           ret = func(request)
           return ret
        else :
            next_url = request.path_info
            print(next_url)
            return  redirect('/app02/login/?next={}'.format(next_url))
    return wrapper
@timmer
def index(request):
    return render(request, 'app02/index.html')

 注销登录，删除Session和Cookie数据

def logout(request):
    request.session.flush()   # request.session.delete()只删除session不删除cookie
    return redirect("/app02/login")

 request.session.set_expiry(value)

value如果是整数，就是多少秒之后失效

value如果是datatime或者timemelta，session就会在这个时间后失效

value如果是0，关闭浏览器就失效。

SESSION_COOKIE_AGE=129600  session的Cookie失效日期默认为2周。

SESSION_SAVE_EVERY_REQUEST = True    设置后，每一次的请求都重新保存session

默认session修改后才重新保存

自定义分页

首选数据库批量创建数据

import  os,sys
if __name__ == "__main__":
    os.environ.setdefault("DJANGO_SETTINGS_MODULE", "ajax_demo.settings")
    import django
    django.setup()
    from app01  import models
    objs = [models.Userinfo(name="第{}个".format(i))  for i  in range(105)]
    models.Userinfo.objects.bulk_create(objs,10)

 views.py

#分页
def  page_s(request):
    objs = models.Userinfo.objects.all()
    page_line = len(objs)
    m,n = divmod(page_line,10)
    page_sum = m
    if n>0:
        page_sum = m+1
    # page_sum=[i for i  in range(1,page_sum+1)]
    Page_sum = page_sum+1
    page_id = request.GET.get('page_id')
    page_start = 0
    page_end = 10
    pro_page_id = 0
    net_page_id = 2
    page_sum_start = 1
    page_sum_end = 11
    if page_sum<11:
        page_sum_end=page_sum
    if page_id :
        page_id = int(page_id)
        page_start = (page_id-1)*10
        page_end = (page_id)*10
        pro_page_id = page_id-1
        net_page_id = page_id+1
        if page_id - 5 >0 and page_id +5 <=page_sum:
            page_sum_start = page_id -5
            page_sum_end = page_id +5
        if page_id +5 >page_sum:
            page_sum_start = page_sum-10
            page_sum_end = page_sum
    page_sum =[i for i in range(page_sum_start,page_sum_end+1)]
    print(page_start,page_end)
    objs = objs[page_start:page_end]
    print(objs)
    return render(request,'page_s.html',
                  {"objs":objs,
                   "page_sum":page_sum,
                   "pro_page_id":pro_page_id,
                   "net_page_id":net_page_id,
                   "Page_sum":Page_sum})

 page_s.html

<!DOCTYPE html>
<html lang="zh-CN">
<head>
    <meta charset="UTF-8">
    <title></title>
    <link rel="stylesheet" href="/static/bootstrap/css/bootstrap.min.css">
</head>
<body>
<table>
    <thead>
    <tr>
        <td></td>
    </tr>
    </thead>
    <tbody>
    {% for obj in objs %}

        <tr>
            <td>
                {{ obj.name }}
            </td>
        </tr>
    {% endfor %}
    </tbody>
</table>
<nav aria-label="Page navigation" class="pull-right">
    <ul class="pagination">
        <li>
            <a href="/page_s/?page_id={{ pro_page_id }}" class="btn {% if pro_page_id == 0  %} disabled {% endif %} "  aria-label="Previous">
                <span aria-hidden="true">«</span>
            </a>
        </li>
        {% for page_sigle in page_sum  %}
        <li><a href="/page_s/?page_id={{ page_sigle }}">{{ page_sigle }}</a></li>
        {% endfor %}
        <li>
            <a href="/page_s/?page_id={{ net_page_id }}"  class="btn {% if net_page_id == Page_sum  %} disabled {% endif %} aria-label="Next">
                <span aria-hidden="true">»</span>
            </a>
        </li>
    </ul>
</nav>
<script src="/static/jquery-3.3.1.min.js"></script>
<script src="/static/bootstrap/js/bootstrap.min.js"></script>
</body>
</html>

 简单分页

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>

Html

内置分页扩展

class CustomPaginator(Paginator):
    def __init__(self, current_page, max_pager_num, *args, **kwargs):
        """
        :param current_page: 当前页
        :param max_pager_num:最多显示的页码个数
        :param args:
        :param kwargs:
        :return:
        """
        self.current_page = int(current_page)
        self.max_pager_num = max_pager_num
        super(CustomPaginator, self).__init__(*args, **kwargs)

    def page_num_range(self):
        # 当前页面
        # self.current_page
        # 总页数
        # self.num_pages
        # 最多显示的页码个数
        # self.max_pager_num
        print(1)
        if self.num_pages < self.max_pager_num:
            return range(1, self.num_pages + 1)
        print(2)
        part = int(self.max_pager_num / 2)
        if self.current_page - part < 1:
            return range(1, self.max_pager_num + 1)
        print(3)
        if self.current_page + part > self.num_pages:
            return range(self.num_pages + 1 - self.max_pager_num, self.num_pages + 1)
        print(4)
        return range(self.current_page - part, self.current_page + part + 1)


L = []
for i in range(999):
    L.append(i)

def index(request):
    current_page = request.GET.get('p')
    if not current_page:
        current_page=1
    paginator = CustomPaginator(current_page, 11, 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)
        print('post::::',posts,type(posts))
        # 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:
        print('*'*120)
        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>
    <link rel="stylesheet" href="/static/bootstrap/css/bootstrap.min.css">
</head>
<body>
<div class="container">
    <ul>
    {% for item in posts %}
        <li>{{ item }}</li>
    {% endfor %}
</ul>

<div class="pagination">


<nav aria-label="Page navigation">
  <ul class="pagination">

  {% if posts.has_previous %}
    <li>
      <a href="?p={{ posts.previous_page_number }}"  aria-label="Previous">
        <span aria-hidden="true">&laquo;</span>
      </a>
    </li>
  {% endif %}
    {% for i in posts.paginator.page_num_range %}
        <li><a href="?p={{ i }}">{{ i }}</a></li>
    {% endfor %}
      {% if posts.has_next %}
    <li>
      <a href="?p={{ posts.next_page_number }}"  aria-label="Next">
        <span aria-hidden="true">&raquo;</span>
      </a>
    </li>
      {% endif %}
  </ul>
</nav>
{#<span class="current">#}
{#Page {{ posts.number }} of {{ posts.paginator.num_pages }}.#}
{#</span>#}

</div>
</div>

<script  src="/static/jquery-3.3.1.js"></script>
<script  src="/static/bootstrap/js/bootstrap.min.js"></script>
</body>
</html>