django之session与分页(实例讲解)

前面我们介绍了cookies，主要应用在用户登录上，保存用户登录状态，不过cookies直接放在了浏览器上，安全性较低，所以我们便引出了session功能与cookies相同，不同的是它放在了客户端，相比较cookies来说安全性更高。还有分页，这是一个比较常用的功能。

一、session

1、基本语法：

1、设置Sessions值
   request.session['session_name'] ="admin"
2、获取Sessions值
   session_name = request.session["session_name"]
   session_name = request.session.get("session_name")
3、删除Sessions值
   del request.session["session_name"]
   request.session.flush()
4、检测是否操作session值
   if "session_name" is request.session :

2、解析图

3、实例

1）views

def login(requset):
 if requset.method=="POST":
  username=requset.POST.get("user")
  password=requset.POST.get("pwd")
  ret=models.UserInfo.objects.filter(username=username,password=password)
  if ret:
   requset.session["IS_LOGON"]=True
   requset.session["USER"]=username

   return redirect("/home/")
  else:
   return redirect("/login/")

 return render(requset,"login.html")

def home(request):
 ret=request.session.get("IS_LOGON",None)

 if ret :
  username=request.session.get("USER")
  return render(request, "home.html",locals())
 else:
  return redirect("/login/")

2）template

<form action="/login/" method="post">
 {% csrf_token %}
 <p>姓名 <input type="text" name="user"></p>
 <p>密码 <input type="password" name="pwd"></p>
 <input type="submit">
</form>

二、分页

1、view

from django.shortcuts import render,HttpResponse

# Create your views here.
from app01.models import *
from django.core.paginator import Paginator, EmptyPage, PageNotAnInteger

def index(request):

 '''
 批量导入数据:

 Booklist=[]
 for i in range(100):
  Booklist.append(Book(title="book"+str(i),price=30+i*i))
 Book.objects.bulk_create(Booklist)
 '''

 '''
分页器的使用:

 book_list=Book.objects.all()

 paginator = Paginator(book_list, 10)

 print("count:",paginator.count)   #数据总数
 print("num_pages",paginator.num_pages) #总页数
 print("page_range",paginator.page_range) #页码的列表

 page1=paginator.page(1) #第1页的page对象
 for i in page1:   #遍历第1页的所有数据对象
  print(i)

 print(page1.object_list) #第1页的所有数据

 page2=paginator.page(2)

 print(page2.has_next())   #是否有下一页
 print(page2.next_page_number()) #下一页的页码
 print(page2.has_previous())  #是否有上一页
 print(page2.previous_page_number()) #上一页的页码

 # 抛错
 #page=paginator.page(12) # error:EmptyPage

 #page=paginator.page("z") # error:PageNotAnInteger

 '''

 book_list=Book.objects.all()

 paginator = Paginator(book_list, 10)
 page = request.GET.get('page',1)
 currentPage=int(page)

 try:
  print(page)
  book_list = paginator.page(page)
 except PageNotAnInteger:
  book_list = paginator.page(1)
 except EmptyPage:
  book_list = paginator.page(paginator.num_pages)

 return render(request,"index.html",{"book_list":book_list,"paginator":paginator,"currentPage":currentPage})

2、templates

<!DOCTYPE html>
<html lang="en">
<head>
 <meta charset="UTF-8">
 <title>Title</title>
 <link rel="stylesheet" href="https://cdn.bootcss.com/bootstrap/3.3.7/css/bootstrap.min.css" rel="external nofollow"
 integrity="sha384-BVYiiSIFeK1dGmJRAkycuHAHRg32OmUcww7on3RYdg4Va+PmSTsz/K68vbdEjh4u" crossorigin="anonymous">
</head>
<body>

<div class="container">

 <h4>分页器</h4>
 <ul>

  {% for book in book_list %}
    <li>{{ book.title }} -----{{ book.price }}</li>
  {% endfor %}

  </ul>

 <ul class="pagination" id="pager">

     {% if book_list.has_previous %}
     <li class="previous"><a href="/index/?page={{ book_list.previous_page_number }}" rel="external nofollow" >上一页</a></li>
     {% else %}
     <li class="previous disabled"><a href="#" rel="external nofollow" rel="external nofollow" >上一页</a></li>
     {% endif %}

     {% for num in paginator.page_range %}

      {% if num == currentPage %}
      <li class="item active"><a href="/index/?page={{ num }}" rel="external nofollow" rel="external nofollow" >{{ num }}</a></li>
      {% else %}
      <li class="item"><a href="/index/?page={{ num }}" rel="external nofollow" rel="external nofollow" >{{ num }}</a></li>

      {% endif %}
     {% endfor %}

     {% if book_list.has_next %}
     <li class="next"><a href="/index/?page={{ book_list.next_page_number }}" rel="external nofollow" >下一页</a></li>
     {% else %}
     <li class="next disabled"><a href="#" rel="external nofollow" rel="external nofollow" >下一页</a></li>
     {% endif %}

   </ul>
</div>

</body>
</html>

3、扩展

def index(request):

 book_list=Book.objects.all()

 paginator = Paginator(book_list, 15)
 page = request.GET.get('page',1)
 currentPage=int(page)

 # 如果页数十分多时，换另外一种显示方式
 if paginator.num_pages>30:

  if currentPage-5<1:
   pageRange=range(1,11)
  elif currentPage+5>paginator.num_pages:
   pageRange=range(currentPage-5,paginator.num_pages+1)

  else:
   pageRange=range(currentPage-5,currentPage+5)

 else:
  pageRange=paginator.page_range

 try:
  print(page)
  book_list = paginator.page(page)
 except PageNotAnInteger:
  book_list = paginator.page(1)
 except EmptyPage:
  book_list = paginator.page(paginator.num_pages)

 return render(request,"index.html",locals())

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