DjangoF,Q查询,Templatetags,session,中间件

#正向查询(表里有外键字段):获取作者对象,对多对多关系表中的book_id做操作
author_obj &＃61; models.Author.objects.last()#设置多对多关系
#方式一:
author_obj.books.set([1,2])#方式二:
ret&＃61; models.Book.objects.filter(id__in&＃61;[1, 4, 16])
# author_obj.books.set(ret)
author_obj.books.set([*ret])#清空多对多关系
author_obj.books.set([])

#增删多对多的关系

#方式一:删ID
author_obj.books.remove(4)
author_obj.books.add(4)

#方式二:删对象
author_obj.books.remove(models.Book.objects.get(id&＃61;4))
author_obj.books.add(models.Book.objects.get(id&＃61;16))

#清空所有多对多的关系
author_obj.books.clear()

#创建一个新的书籍对象,并且和当前的作者做关联
author_obj.books.create(title&＃61;&＃39;高等英语&＃39;,publisher_id&＃61;3,price&＃61;150)#反向查询(表里无外键字段) 获取书籍对象,对多对多关系表中的author_id进行操作
book_obj &＃61; models.Book.objects.last()
print(book_obj.author_set,book_obj.author_set.all())
#app01.Author.None >]>
book_obj.author_set.add(4)

models.py
class Book(models.Model):title&＃61;models.CharField(max_length&＃61;32) #创建的属性是字符串 ---> title字段price&＃61;models.IntegerField()publisher &＃61; models.ForeignKey(&＃39;Publisher&＃39;) #创建的属性是一个主表Publisher对象 -->publiserh_id字段def __str__(self):return f&＃39;<书籍:{self.title} - 价格:{self.price}-出版社:{self.publisher}>&＃39;class Author(models.Model):author_name&＃61;models.CharField(max_length&＃61;32)books&＃61;models.ManyToManyField(to&＃61;&＃39;Book&＃39;) #django自动生成第三张表def __str__(self):return f&＃39;<作者:{self.author_name},books{self.books}>&＃39;views.py
def author_list(request):author_obj &＃61; models.Author.objects.all()return render(request,&＃39;author_list.html&＃39;,{&＃39;author_obj&＃39;:author_obj})class Addauthor(View):def get(self,request):books &＃61; models.Book.objects.all()return render(request,&＃39;author_add.html&＃39;,{&＃39;base&＃39;:&＃39;base.html&＃39;,&＃39;books&＃39;:books})def post(self,request):new_name&＃61;self.request.POST.get(&＃39;author_name&＃39;)# bood_id &＃61;self.request.POST.get(&＃39;book&＃39;) bood_id &＃61;self.request.POST.getlist(&＃39;book&＃39;) # getlist:键值对应的是一个列表的时候需要用getlistprint(bood_id)#[&＃39;1&＃39;, &＃39;2&＃39;, &＃39;3&＃39;]#创建作者对象author_obj&＃61;models.Author.objects.create(author_name&＃61;new_name)#建立作者和书籍得关系#print(models.Author.books,type(models.Author.books))# #通过关联对象设置第三张表,可以一次性设置多个关系
author_obj.books.set(bood_id)return self.get(request)class Editauthor(View):def get(self,request,edit_id):books &＃61; models.Book.objects.all()author_obj &＃61; models.Author.objects.filter(id&＃61;edit_id).first()return render(request,&＃39;author_edit.html&＃39;,{&＃39;books&＃39;:books,&＃39;author_obj&＃39;:author_obj,&＃39;base&＃39;:&＃39;base.html&＃39;})def post(self,request,edit_id):#获取修改的对象new_name &＃61; self.request.POST.get(&＃39;author_name&＃39;)book_id &＃61; self.request.POST.getlist(&＃39;book&＃39;)author_obj &＃61; models.Author.objects.filter(id&＃61;edit_id).first()#方式一author_obj.author_name &＃61;new_nameauthor_obj.save()#方式二# author_obj &＃61; models.Author.objects.filter(id&＃61;edit_id)# author_obj.update(author_name&＃61;new_name)#author_obj.first().books.set(book_id)
author_obj.books.set(book_id)return redirect(reverse(&＃39;author&＃39;))

from django.db.models import Sum,Avg,Max,Min,Count

#聚合 aggregate终止语句
ret &＃61; models.Book.objects.aggregate(Sum(&＃39;price&＃39;),Count(&＃39;price&＃39;),max&＃61;Max(&＃39;price&＃39;))
print(ret,type(ret))
#{&＃39;max&＃39;: 255, &＃39;price__sum&＃39;: 1928, &＃39;price__count&＃39;: 11} #Book与author对象是多对多的关系
#查Book的对象的所有内容,拼接一个Count(&＃39;author&＃39;)字段,相当于把聚合结果放到对象中
ret &＃61; models.Book.objects.annotate(Count(&＃39;author&＃39;)).values()
for i in ret:print(i)#每个出版社价格最低的书
ret2 &＃61; models.Publisher.objects.annotate(Min(&＃39;bk__price&＃39;)).values()
print(ret2)#values按指定字段去分组
ret3&＃61;models.Book.objects.values(&＃39;publisher__name&＃39;).annotate(min&＃61;Min(&＃39;price&＃39;)).values(&＃39;publisher__name&＃39;,&＃39;min&＃39;)
# ret3&＃61;models.Book.objects.values(&＃39;publisher__name&＃39;).annotate(min&＃61;Min(&＃39;price&＃39;)).values() 错误 ,分组之后只能取分组相关的字段
for i in ret3:print(i)
#SELECT &＃96;app01_publisher&＃96;.&＃96;name&＃96;, MIN(&＃96;app01_book&＃96;.&＃96;price&＃96;) AS &＃96;min&＃96; FROM &＃96;app01_book&＃96; INNER JOIN &＃96;app01_publisher&＃96;
# ON (&＃96;app01_book&＃96;.&＃96;publisher_id&＃96; &＃61; &＃96;app01_publisher&＃96;.&＃96;id&＃96;) GROUP BY &＃96;app01_publisher&＃96;.&＃96;name&＃96; ORDER BY NULL;#查询大于一个作者的书
ret &＃61; models.Book.objects.annotate(count&＃61;Count(&＃39;author&＃39;)).filter(count__gt&＃61;1).values()
for i in ret:print(i)#根据作者的数量排序
ret &＃61;models.Book.objects.annotate(count&＃61;Count(&＃39;author&＃39;)).order_by(&＃39;count&＃39;)#查询每个作者出书的总价格
ret &＃61; models.Author.objects.annotate(Sum(&＃39;books__price&＃39;)).values()

from django.db.models import F,Q#F 用来取表中动态的字段
#查询库存小于销量的书籍 比较动态的字段
ret &＃61; models.Book.objects.filter(inventory__lt&＃61;F(&＃39;sale&＃39;)).values()
# print(ret)

ret1 &＃61; models.Book.objects.update(sale&＃61;F(&＃39;sale&＃39;)*2)#Q 可以将查询条件变成 或的 关系
#逗号连接的条件都是 and的关系
ret &＃61; models.Book.objects.filter(id__gte&＃61;7,title&＃61;&＃39;史记&＃39;).values()
print(ret)#使用Q查询可以 使用 与 或 非三种关系
ret2 &＃61; models.Book.objects.filter(Q(id__lt&＃61;2)|Q(id__gte&＃61;13)).values()
print(ret2)
ret3 &＃61; models.Book.objects.filter(Q(id__lt&＃61;2) & Q(id__gte&＃61;13)).values()
print(ret3)
ret4&＃61;models.Book.objects.filter(~Q(Q(id__lt&＃61;2)|Q(id__gte&＃61;13))).values()
for i in ret4:print(i)

#事务 出现异常数据库不进行任何操作
from django.db import transaction
try:with transaction.atomic():models.Book.objects.update(price&＃61;F(&＃39;price&＃39;)&＃43;50)models.Book.objects.get(id&＃61;100) #异常models.Book.objects.update(price&＃61;F(&＃39;price&＃39;)-30)
except Exception as e:print(e)

my_tags.py

from django import templateregister&＃61;template.Library() #register 固定的名字

my_tags.py
&＃64;register.filter(name&＃61;&＃39;ddb&＃39;)
def add_str(value,arg):ret&＃61;f&＃39;{value}_{arg}&＃39;return rethtml
#加载文件
{% load my_tags %}
{#{{ &＃39;alex&＃39;|add_str:&＃39;xxxb&＃39; }}#}
#使用文件定义的函数
{{ &＃39;alex&＃39;|ddb:&＃39;xxxb&＃39; }}
#浏览器:alex_xxxb views.py
def tag_test(request):return render(request,&＃39;tag_test.html&＃39;)

my_tags.py
#装饰器后面要加括号,否则在pychram中可以使用但是会漂黄
&＃64;register.simple_tag()
def string_join(*args,**kwargs):ret &＃61; &＃39;_&＃39;.join(args) &＃43; &＃39;*&＃39;.join(kwargs.values())return rethtml
{% load my_tags %}
{% string_join &＃39;dddd&＃39; &＃39;sdfsdf&＃39; k1&＃61;&＃39;erwer&＃39; k2&＃61;&＃39;2131&＃39; %}
#浏览器:dddd_sdfsdferwer*2131

my_tags.py
&＃64;register.inclusion_tag(&＃39;pagination.html&＃39;)
def pagination(total,page):return {&＃39;total&＃39;:range(1,total&＃43;1),&＃39;page&＃39;:page}author_list.html
#需要使用代码段的页面
{% load my_tags %}{% pagination 6 1%}pagination.html
#代码段的渲染{% for num in total %}{% if num &＃61;&＃61; page %}

COOKIE的方法
普通COOKIE ret是httpresponse对象
设置:ret.set_COOKIE(key,value&＃61;&＃39;&＃39;,max_age&＃61;None path&＃61;&＃39;/&＃39;)
字段解释:key:COOKIE键 value:COOKIE值 ,max_age:x秒 COOKIE超时时间 ,path:COOKIE生效的路径
取COOKIE:request.COOKIES.get(&＃39;键&＃39;)

 加密COOKIE
 设置:ret.set_signed_COOKIE(&＃39;is_login&＃39;,&＃39;abc&＃39;,salt&＃61;&＃39;xxxx&＃39;)
 salt:加密盐
 取COOKIE:request.get_signed_COOKIE(&＃39;is_login&＃39;,salt&＃61;&＃39;xxxx&＃39;,default&＃61;&＃39;&＃39;,max_age&＃61;5)

 删除COOKIE
#对浏览器中的COOKIE 键与值进行删除
ret.delete_COOKIE(&＃39;is_login&＃39;) 

#实例
def login_required(func):def inner(request,*args,**kwargs):# is_login &＃61; request.COOKIES.get(&＃39;is_login&＃39;)is_login &＃61; request.get_signed_COOKIE(&＃39;is_login&＃39;,salt&＃61;&＃39;xxxx&＃39;,default&＃61;&＃39;&＃39;,max_age&＃61;5)# 对于加密的来说,不加default参数会获取不到COOKIE的值而抛出异常KeyError at / app01 / publisher_list /&＃39;is_login&＃39;print(is_login)if is_login !&＃61;&＃39;abc&＃39;:returnurl&＃61;request.path_infoif returnurl:return redirect((f&＃39;{reverse("login")}?return_url&＃61;{returnurl}&＃39;))return redirect(reverse(&＃39;login&＃39;))else:ret &＃61; func(request,*args,**kwargs)return retreturn innerdef login(request):error_msg&＃61;&＃39;&＃39;if request.method &＃61;&＃61; &＃39;POST&＃39;:username &＃61; request.POST.get(&＃39;username&＃39;,&＃39;&＃39;)password &＃61; request.POST.get(&＃39;password&＃39;,&＃39;&＃39;)if username &＃61;&＃61; &＃39;alex&＃39; and password &＃61;&＃61; &＃39;123&＃39;:return_url&＃61;request.GET.get(&＃39;return_url&＃39;)if return_url:ret &＃61; redirect(return_url)else:ret &＃61; redirect(reverse(&＃39;publisher&＃39;))# ret.set_COOKIE(&＃39;is_login&＃39;,&＃39;1&＃39;,max_age&＃61;5,path&＃61;&＃39;/app01/pub_list/&＃39;)#不加密的COOKIE 超时时间5秒,COOKIE生效的路径ret.set_signed_COOKIE(&＃39;is_login&＃39;,&＃39;abc&＃39;,salt&＃61;&＃39;xxxx&＃39;) #加密的COOKIEreturn reterror_msg &＃61; &＃39;用户名或密码错误&＃39;return render(request,&＃39;login.html&＃39;,{&＃39;error_msg&＃39;:error_msg})

def logout(request):
#删除COOKIE
ret &＃61; redirect(reverse(&＃39;login&＃39;))
ret.delete_COOKIE(&＃39;is_login&＃39;)
return ret

session的设置
#request.session.setdefault(&＃39;is_login&＃39;,1)
request.session[&＃39;is_login&＃39;]&＃61;&＃39;1&＃39;
request.session.set_expiry(5) #只删除浏览器的COOKIE 每次新连接的时候都使用新的COOKIE,数据库中的数据还保存,相当于一个新的客户端取连接

session的获取
print(request.session)
#
is_login &＃61; request.session.get(&＃39;is_login&＃39;)
#request.session[&＃39;is_login&＃39;]

session的删除
del request.session[&＃39;is_login&＃39;] #浏览器和数据库session值都在,只是在程序逻辑中删除了KEY

request.session.delete()#删除数据库session值,不删除浏览器的COOKIE(sessionid),但每次重新访问url的时候都会重新得到一个新的sessionid,数据库也会有此ID相对应的值

request.session.flush() #同时删除浏览器的COOKIE(sessionid)和数据库session值

session的配置
SESSION_ENGINE &＃61; &＃39;django.contrib.sessions.backends.db&＃39;
SESSION_COOKIE_AGE &＃61; 1209600

#注册自定义的中间件
#settings.py
MIDDLEWARE &＃61; [&＃39;django.middleware.security.SecurityMiddleware&＃39;,&＃39;django.contrib.sessions.middleware.SessionMiddleware&＃39;,&＃39;django.middleware.common.CommonMiddleware&＃39;,&＃39;django.middleware.csrf.CsrfViewMiddleware&＃39;,&＃39;django.contrib.auth.middleware.AuthenticationMiddleware&＃39;,&＃39;django.contrib.messages.middleware.MessageMiddleware&＃39;,&＃39;django.middleware.clickjacking.XFrameOptionsMiddleware&＃39;,&＃39;app01.middlewares.mymiddleware.MD1&＃39;,&＃39;app01.middlewares.mymiddleware.MD2&＃39;,
]#mymiddleware.py
from django.utils.deprecation import MiddlewareMixin
from django.shortcuts import HttpResponse
class MD1(MiddlewareMixin):def process_request(self,request):print(&＃39;MD1 reuqest内存地址&＃39;,id(request))print(&＃39;MD1的process_request&＃39;)# return HttpResponse(&＃39;MD1的process_request&＃39;) 如果返回,后面的流程不执行了 包括MD2中的process_requestclass MD2(MiddlewareMixin):def process_request(self,request):print(&＃39;MD2的process_request&＃39;)# return HttpResponse(&＃39;MD2的process_request&＃39;)#views.py
def index(request):print(&＃39;index request内存地址&＃39;,id(request))print(&＃39;这是index视图&＃39;)return HttpResponse(&＃39;视图index中的ok&＃39;)
#执行时间
在视图函数执行之前
#参数
request(请求对象) 与视图中的request是一个对象
#执行顺序
按照settings中注册的顺序, 顺序执行
#返回值
正常流程:返回一个None
response对象,哪个process_request 只要return response对象之后 直接不执行后面的流程,按照注册顺序决定返回顺序#无返回值的执行结果
&＃39;&＃39;&＃39;
MD1 reuqest内存地址 1815873977760
MD1的process_request
MD2的process_request
index request内存地址 1815873977760
这是index视图
&＃39;&＃39;&＃39;

#当MD1与MD2都有返回值时的执行结果
&＃39;&＃39;&＃39;

 MD1 reuqest内存地址 2104042671576
 MD1的process_reques

&＃39;&＃39;&＃39;

#当MD2有返回值,MD1无返回值时的执行结果
&＃39;&＃39;&＃39;
MD1 reuqest内存地址 2118239296984
MD1的process_request
MD2的process_request

&＃39;&＃39;&＃39;

class MD1(MiddlewareMixin):def process_request(self,request):# print(&＃39;MD1 reuqest内存地址&＃39;,id(request))print(&＃39;MD1的process_request&＃39;)# return HttpResponse(&＃39;MD1的process_request&＃39;)def process_response(self,request,response):print(&＃39;MD1 response内存地址&＃39;,id(response))print(&＃39;MD1的process_response&＃39;)return responseclass MD2(MiddlewareMixin):def process_request(self,request):print(&＃39;MD2的process_request&＃39;)# return HttpResponse(&＃39;MD2的process_request&＃39;)def process_response(self,request,response):print(&＃39;MD2 response内存地址&＃39;, id(response))print(&＃39;MD2的process_response&＃39;)return response#执行时间
在视图函数执行之后#参数
request(请求对象),与视图中的request时一个对象
response(响应对象):视图返回的响应对象#执行顺序
按照注册的顺序 倒叙返回response对象#返回值
response对象:必须返回#正常流程的执行结果
&＃39;&＃39;&＃39;
MD1的process_request
MD2的process_request
这是index视图
视图 2103546390848
MD2 response内存地址 2103546390848
MD2的process_response
MD1 response内存地址 2103546390848
MD1的process_response
&＃39;&＃39;&＃39;

class MD1(MiddlewareMixin):def process_request(self,request):print(&＃39;MD1的process_request&＃39;)def process_response(self,request,response):print(&＃39;MD1的process_response&＃39;)return responsedef process_view(self,request,view_func,view_args,view_kwargs):print(view_func)print(view_args)print(view_kwargs)print(&＃39;MD1的process_view&＃39;)# return HttpResponse(&＃39;MD1 process view&＃39;)class MD2(MiddlewareMixin):def process_request(self,request):print(&＃39;MD2的process_request&＃39;)def process_response(self,request,response):print(&＃39;MD2的process_response&＃39;)return responsedef process_view(self,request,view_func,view_args,view_kwargs):print(&＃39;MD2的process_view&＃39;)#执行时间
在视图函数执行之前,在process_request之后,在路由匹配之后#参数
request :
请求对象 和视图的参数是一个
view_func&＃xff1a;视图函数
view_args&＃xff1a;视图函数的位置参数
view_kwargs&＃xff1a;视图函数的关键字参数#执行顺序
按照中间件注册顺序,顺序执行#返回值
None:正常流程
response对象 : 如果中间件中的process_view有return response对象,后续的process_view 以及视图都不执行, 直接按照process_response倒叙返回#正常流程执行结果
&＃39;&＃39;&＃39;
MD1的process_request
MD2的process_request

(&＃39;1&＃39;,)
{&＃39;xxx&＃39;: 222}
MD1的process_view
MD2的process_view
这是index视图
MD2的process_response
MD1的process_response
&＃39;&＃39;&＃39;

mymiddleware.py
class MD1(MiddlewareMixin):def process_request(self,request):print(&＃39;MD1的process_request&＃39;)def process_response(self,request,response):print(&＃39;MD1的process_response&＃39;)return responsedef process_view(self,request,view_func,view_args,view_kwargs):print(&＃39;MD1的process_view&＃39;)def process_template_response(self,request,response):print(&＃39;MD1的process_template_response&＃39;)return responseclass MD2(MiddlewareMixin):def process_request(self,request):print(&＃39;MD2的process_request&＃39;)def process_response(self,request,response):print(&＃39;MD2的process_response&＃39;)return responsedef process_view(self,request,view_func,view_args,view_kwargs):print(&＃39;MD2的process_view&＃39;)def process_template_response(self, request, response):print(&＃39;MD2的process_template_response&＃39;)return response
views
def index(request,*args,**kwargs):print(&＃39;这是index视图&＃39;)ret &＃61; HttpResponse(&＃39;视图index中的ok&＃39;)def pro_template():return HttpResponse(&＃39;这是xxxx&＃39;)ret.render &＃61;pro_templatereturn ret
#执行时间
在视图执行之后
触发条件:视图返回响应对象之后有一个render的方法#参数
request(请求对象),与视图中的request时一个对象
response(响应对象):视图返回的响应对象#执行顺序
按注册顺序倒叙执行#返回值
必须返回response对象#正常流程执行结果
&＃39;&＃39;&＃39;
MD1的process_request
MD2的process_request
MD1的process_view
MD2的process_view
这是index视图
MD2的process_template_response
MD1的process_template_response
MD2的process_response
MD1的process_response
&＃39;&＃39;&＃39;

class MD1(MiddlewareMixin):def process_request(self,request):print(&＃39;MD1的process_request&＃39;)def process_response(self,request,response):print(&＃39;MD1的process_response&＃39;)return responsedef process_view(self,request,view_func,view_args,view_kwargs):print(&＃39;MD1的process_view&＃39;)def process_template_response(self,request,response):print(&＃39;MD1的process_template_response&＃39;)return responsedef process_exception(self,request,exception):print(exception)print(&＃39;MD1的process_exception&＃39;)class MD2(MiddlewareMixin):def process_request(self,request):print(&＃39;MD2的process_request&＃39;)def process_response(self,request,response):print(&＃39;MD2的process_response&＃39;)return responsedef process_view(self,request,view_func,view_args,view_kwargs):print(&＃39;MD2的process_view&＃39;)def process_template_response(self, request, response):print(&＃39;MD2的process_template_response&＃39;)return responsedef process_exception(self, request, exception):print(exception)print(&＃39;MD2的process_exception&＃39;)return HttpResponse(str(exception))
#执行时间
触发条件:视图层面有错误之后去执行#参数
request(请求对象和视图的参数一样)
exception:错误对象#执行顺序
按照中间件注册顺序倒叙执行#返回值
None:正常报错
response对象:之后的中间件的process_excetion方法都不行了,之后倒叙执行所有中间件的process_response#执行结果
&＃39;&＃39;&＃39;
MD1的process_request
MD2的process_request
MD1的process_view
MD2的process_view
这是index视图
invalid literal for int() with base 10: &＃39;aaa&＃39;
MD2的process_exception
MD2的process_response
MD1的process_response&＃39;&＃39;&＃39;

&＃39;&＃39;&＃39;
1.浏览器发起url请求,wsgi接收请求的url进行socket封装(用户IP,浏览器版本,用户系统等等汇总到一个request类中)
2.经过所有的中间件(5种方法都存在的情况):a.顺序执行每个注册的中间件的process_request,正常流程返回None,一旦有某个process_request返回了response后面的流程都不走,直接返回给浏览器.b.路由系统匹配url之后,顺序执行每个process_view,正常流程返回None,一旦某个process_view返回了None,后面的流程都不走,直接倒叙执行每个process_response,最后返回浏览器.c.views视图与model(db处理)和template(filter和tags处理)进行交互之后,拿到对象用httpresponse对象返回给 process_reponse ,倒叙执行每个process_response,最后返回给浏览器d.如果视图返回对象之后有一个render方法,可以触发process_template_response,倒叙执行每个process_template_response,必须返回一个response给process_response,倒叙执行每个process_response,最后返回给浏览器f.如果视图层面有异常会触发process_exception且不会去执行process_template_response,倒叙执行每个process_exception,一但有一个process_exception返回了response,后续的process_exception都不执行,直接返回给process_response去倒叙执行每个process_response,最后返回给浏览器.
&＃39;&＃39;&＃39;