Django基础之三（类视图）

摘要：类视图简介视图是一个可调用的对象，它接收一个请求然后返回一个响应，这个可调用对象可以不只是函数，提供一些可以用作视图的类基于类的视图使用对象实现视图，它提供除函数视图之外的另外一种方式属性添加未知的请求方法方法将类视图转换成可被调用的函数视

视图是一个可调用的对象，它接收一个请求然后返回一个响应，这个可调用对象可以不只是函数，Django提供一些可以用作视图的类
基于类的视图使用Python 对象实现视图，它提供除函数视图之外的另外一种方式

属性

http_method_names：添加未知的请求方法

方法

as_view()：将类视图转换成可被调用的函数视图
dispatch()： 根据请求去匹配http_method_names下的对应函数去处理请求
http_method_not_allowed()：返回405错误

实例

from django.views import View
class IndexView(View):
    http_method_names = ["get", "post", "put", "patch", "delete", "head", "options", "trace","list"]
    def get(self,request,*args,**kwargs):
        return HttpResponse(IndexView)

    def post(self,request,*args,**kwargs):
        data = request.POST
        return HttpResponse(data)
    #需要将list方法加入 http_method_names，否则会经过，dispatch，http_method_not_allowed()：返回405错误
    def list(self,request,*args,**kwargs):
        return HttpResponse("ListView")
请求方式：
In [27]: import requests                                                                
In [28]: url = "http://192.168.33.10:8080/dashboard/index/"                             
In [29]: res = requests.request("list",url)                                             
In [30]: res.content                                                                    
Out[30]: b"ListView"

数据准备

In [3]: from django.contrib.auth.models import User
In [4]: for n in range(1,101): 
...:     User.objects.create_user("wanghui-{}".format(n),"wanghui-{}@alibaba.com".format(n),"123456") 
In [5]: User.objects.all()[1:10]      

类视图

class UserView(View):
    #http_method_names = ["get", "post", "put", "patch", "delete", "head", "options", "trace","list"]
    def get(self,request,*args,**kwargs):
      #展示数据
        # queryset = User.objects.all()
        # return HttpResponse(queryset)
        try:
            page = int(request.GET.get("page"))
        except:
            page = 1
        if page < 1:
            page = 1
        per = 10
        end = page * per
        start = end - per
        queryset = User.objects.all()[start:end]
        data = [{"id":user.id,"username":user.username,"email":user.email} for user in queryset]
        return JsonResponse(data,safe=False)

class Paginator(object_list, per_page, orphans=0, allow_empty_first_page=True)
属性
- Paginator.count 所有页面的objects总数
- Paginator.num_pages 页面总数
- Paginator.page_range 页码的范围，从1开始，例如[1, 2, 3, 4]
方法
- Paginator.page(number) 返回一个page对象,number， 当前显示的是第几页

Page对象

class Page(object_list, number, paginator)

方法
- Page.has_next() 如果有下一页，返回True
- Page.has_previous() 如果有上一页，返回 True
- Page.has_other_pages() 如果有上一面或下一页，返回True
- Page.next_page_number() 返回下一页的页码.如果不存在,抛出InvalidPage异常
- Page.previous_page_number() 返回上一页的页码.如果不存在,抛出InvalidPage异常
- Page.start_index() 返回当前页上的第一个对象，相对于分页列表的所有对象的序号
- Page.end_index() 返回当前页上的最后一个对象，相对于分页列表的所有对象的序号

from django.core.paginator import Paginator
class UserViewV2(View):
    def get(self,request,*args,**kwargs):
        queryset = User.objects.all()
        paginator = Paginator(queryset,10)
        try:
            page = int(request.GET.get("page"))
        except:
            page = 1
        if page < 1:
            page = 1
        page = paginator.page(page)
        data = [{"id":user.id,"username":user.username,"email":user.email} for user in page.object_list]
        return JsonResponse(data,safe=False)

    def post(self,request,*args,**kwargs):
        username = request.POST.get("username")
        userpass = request.POST.get("userpass")
        email = request.POST.get("email")
        if not username or userpass or not email:
            return JsonResponse({"errormsg":"参数有误！"})
        user = User.objects.create(username,email,userpass)
        return JsonResponse({"id":user.id,"username":user.username,"email":user.email})

请求方式

In [1]: import requests                                                                     
In [2]: url = "http://192.168.33.10:8080/dashboard/userview/"                
In [3]: data = {}                                                                                         
In [4]: data["username"] = "zhangsan"                                                     
In [5]: data["userpass"] = "123456"                                                           
In [6]: data["email"] = "zhangsan@alibaba.com"                                     
In [7]: requests.post(url,data)                                                                 
Out[7]: