python自动化开发-[第二十一天]-form验证,中间件,缓存,信号,admin后台
今日概要:
1、form表单进阶
2、中间件
3、缓存
4、信号
5、admin后台
上节课回顾
![](https://images.cnblogs.com/OutliningIndicators/ContractedBlock.gif)
FBV,CBV 序列化 - Django内置 - json.dumps(xxx,cls=) Form验证 - 类 class LoginForm(Form): user = fields.CharField(...) email = fields.EmailField(...) email = fields.ChoiceField( choices=[()..] ) - 添加用户: GET form = LoginForm() {{form.user}} <input type='text' name='user' /> 等待用户输入内容,提交 - 添加用户: POST form = LoginForm(data=request.POST) form.is_valid() form.cleaned_data form.errors - 修改用户: GET /edit/9 obj = models.User.objects.get(id=9) form = LoginForm(initial={'user':obj.user}) {{form.user}} <input type='text' name='user' value='数据库中的用户名' /> 等待用户输入内容,提交 - 修改用户: POST /edit/9 form = LoginForm(data=request.POST) form.is_valid() form.cleaned_data models.User.objects.filter(id=9).update(**form.cleaned_data) form.errors - 补充:可以显示select,但是数据无法实时更新 class LoginForm(Form): user = fields.CharField(...) email = fields.EmailField(...) hobby = fields.ChoiceField( choices=[()..] ) def __init__(self,*args,**kwargs): super.. self.fields['hobby'].choices = ....
一、Form表单进阶
创建Form类时,主要涉及到 【字段】 和 【插件】,字段用于对用户请求数据的验证,插件用于自动生成HTML;
1、Django内置字段如下:
![](https://images.cnblogs.com/OutliningIndicators/ContractedBlock.gif)
Field required=True, 是否允许为空 widget=None, HTML插件 label=None, 用于生成Label标签或显示内容 initial=None, 初始值 help_text='', 帮助信息(在标签旁边显示) error_messages=None, 错误信息 {'required': '不能为空', 'invalid': '格式错误'} show_hidden_initial=False, 是否在当前插件后面再加一个隐藏的且具有默认值的插件(可用于检验两次输入是否一直) validators=[], 自定义验证规则 localize=False, 是否支持本地化 disabled=False, 是否可以编辑 label_suffix=None Label内容后缀 CharField(Field) max_length=None, 最大长度 min_length=None, 最小长度 strip=True 是否移除用户输入空白 IntegerField(Field) max_value=None, 最大值 min_value=None, 最小值 FloatField(IntegerField) ... DecimalField(IntegerField) max_value=None, 最大值 min_value=None, 最小值 max_digits=None, 总长度 decimal_places=None, 小数位长度 BaseTemporalField(Field) input_formats=None 时间格式化 DateField(BaseTemporalField) 格式:2015-09-01 TimeField(BaseTemporalField) 格式:11:12 DateTimeField(BaseTemporalField)格式:2015-09-01 11:12 DurationField(Field) 时间间隔:%d %H:%M:%S.%f ... RegexField(CharField) regex, 自定制正则表达式 max_length=None, 最大长度 min_length=None, 最小长度 error_message=None, 忽略,错误信息使用 error_messages={'invalid': '...'} EmailField(CharField) ... FileField(Field) allow_empty_file=False 是否允许空文件 ImageField(FileField) ... 注:需要PIL模块,pip3 install Pillow 以上两个字典使用时,需要注意两点: - form表单中 enctype="multipart/form-data" - view函数中 obj = MyForm(request.POST, request.FILES) URLField(Field) ... BooleanField(Field) ... NullBooleanField(BooleanField) ... ChoiceField(Field) ... choices=(), 选项,如:choices = ((0,'上海'),(1,'北京'),) required=True, 是否必填 widget=None, 插件,默认select插件 label=None, Label内容 initial=None, 初始值 help_text='', 帮助提示 ModelChoiceField(ChoiceField) ... django.forms.models.ModelChoiceField queryset, # 查询数据库中的数据 empty_label="---------", # 默认空显示内容 to_field_name=None, # HTML中value的值对应的字段 limit_choices_to=None # ModelForm中对queryset二次筛选 ModelMultipleChoiceField(ModelChoiceField) ... django.forms.models.ModelMultipleChoiceField TypedChoiceField(ChoiceField) coerce = lambda val: val 对选中的值进行一次转换 empty_value= '' 空值的默认值 MultipleChoiceField(ChoiceField) ... TypedMultipleChoiceField(MultipleChoiceField) coerce = lambda val: val 对选中的每一个值进行一次转换 empty_value= '' 空值的默认值 ComboField(Field) fields=() 使用多个验证,如下:即验证最大长度20,又验证邮箱格式 fields.ComboField(fields=[fields.CharField(max_length=20), fields.EmailField(),]) MultiValueField(Field) PS: 抽象类,子类中可以实现聚合多个字典去匹配一个值,要配合MultiWidget使用 SplitDateTimeField(MultiValueField) input_date_formats=None, 格式列表:['%Y--%m--%d', '%m%d/%Y', '%m/%d/%y'] input_time_formats=None 格式列表:['%H:%M:%S', '%H:%M:%S.%f', '%H:%M'] FilePathField(ChoiceField) 文件选项,目录下文件显示在页面中 path, 文件夹路径 match=None, 正则匹配 recursive=False, 递归下面的文件夹 allow_files=True, 允许文件 allow_folders=False, 允许文件夹 required=True, widget=None, label=None, initial=None, help_text='' GenericIPAddressField protocol='both', both,ipv4,ipv6支持的IP格式 unpack_ipv4=False 解析ipv4地址,如果是::ffff:192.0.2.1时候,可解析为192.0.2.1, PS:protocol必须为both才能启用 SlugField(CharField) 数字,字母,下划线,减号(连字符) ... UUIDField(CharField) uuid类型 ...
注:UUID是根据MAC以及当前时间等创建的不重复的随机字符串
![](https://images.cnblogs.com/OutliningIndicators/ContractedBlock.gif)
>>> import uuid # make a UUID based on the host ID and current time >>> uuid.uuid1() # doctest: +SKIP UUID('a8098c1a-f86e-11da-bd1a-00112444be1e') # make a UUID using an MD5 hash of a namespace UUID and a name >>> uuid.uuid3(uuid.NAMESPACE_DNS, 'python.org') UUID('6fa459ea-ee8a-3ca4-894e-db77e160355e') # make a random UUID >>> uuid.uuid4() # doctest: +SKIP UUID('16fd2706-8baf-433b-82eb-8c7fada847da') # make a UUID using a SHA-1 hash of a namespace UUID and a name >>> uuid.uuid5(uuid.NAMESPACE_DNS, 'python.org') UUID('886313e1-3b8a-5372-9b90-0c9aee199e5d') # make a UUID from a string of hex digits (braces and hyphens ignored) >>> x = uuid.UUID('{00010203-0405-0607-0809-0a0b0c0d0e0f}') # convert a UUID to a string of hex digits in standard form >>> str(x) '00010203-0405-0607-0809-0a0b0c0d0e0f' # get the raw 16 bytes of the UUID >>> x.bytes b'\x00\x01\x02\x03\x04\x05\x06\x07\x08\t\n\x0b\x0c\r\x0e\x0f' # make a UUID from a 16-byte string >>> uuid.UUID(bytes=x.bytes) UUID('00010203-0405-0607-0809-0a0b0c0d0e0f')
2、Django内置插件:
![](https://images.cnblogs.com/OutliningIndicators/ContractedBlock.gif)
TextInput(Input)
NumberInput(TextInput)
EmailInput(TextInput)
URLInput(TextInput)
PasswordInput(TextInput)
HiddenInput(TextInput)
Textarea(Widget)
DateInput(DateTimeBaseInput)
DateTimeInput(DateTimeBaseInput)
TimeInput(DateTimeBaseInput)
CheckboxInput
Select
NullBooleanSelect
SelectMultiple
RadioSelect
CheckboxSelectMultiple
FileInput
ClearableFileInput
MultipleHiddenInput
SplitDateTimeWidget
SplitHiddenDateTimeWidget
SelectDateWidget
常用选择插件
![](https://images.cnblogs.com/OutliningIndicators/ContractedBlock.gif)
# 单radio,值为字符串 # user = fields.CharField( # initial=2, # widget=widgets.RadioSelect(choices=((1,'上海'),(2,'北京'),)) # ) # 单radio,值为字符串 # user = fields.ChoiceField( # choices=((1, '上海'), (2, '北京'),), # initial=2, # widget=widgets.RadioSelect # ) # 单select,值为字符串 # user = fields.CharField( # initial=2, # widget=widgets.Select(choices=((1,'上海'),(2,'北京'),)) # ) # 单select,值为字符串 # user = fields.ChoiceField( # choices=((1, '上海'), (2, '北京'),), # initial=2, # widget=widgets.Select # ) # 多选select,值为列表 # user = fields.MultipleChoiceField( # choices=((1,'上海'),(2,'北京'),), # initial=[1,], # widget=widgets.SelectMultiple # ) # 单checkbox # user = fields.CharField( # widget=widgets.CheckboxInput() # ) # 多选checkbox,值为列表 # user = fields.MultipleChoiceField( # initial=[2, ], # choices=((1, '上海'), (2, '北京'),), # widget=widgets.CheckboxSelectMultiple # )
注意:写默认值时,多选值对应列表 form = RegisterForm(initial={'city':[1,2],'name':'alex'})
在使用选择标签时,需要注意choices的选项可以从数据库中获取,但是由于是静态字段 ***获取的值无法实时更新***,那么需要自定义构造方法从而达到此目的。
1、方式一
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 | from django.forms import Form from django.forms import widgets from django.forms import fields from django.core.validators import RegexValidator class MyForm(Form): user = fields.ChoiceField( # choices=((1, '上海'), (2, '北京'),), initial = 2 , widget = widgets.Select ) def __init__( self , * args, * * kwargs): #数据循环会先存到feilds里以key,value形式 super (MyForm, self ).__init__( * args, * * kwargs) # self.fields['user'].widget.choices = ((1, '上海'), (2, '北京'),) # 或 self .fields[ 'user' ].widget.choices = models.Classes.objects. all ().value_list( 'id' , 'caption' ) |
2、方式二
使用django提供的ModelChoiceField和ModelMultipleChoiceField字段来实现
1 2 3 4 5 6 7 8 9 10 | from django import forms from django.forms import fields from django.forms import widgets from django.forms import models as form_model from django.core.exceptions import ValidationError from django.core.validators import RegexValidator class FInfo(forms.Form): authors = form_model.ModelMultipleChoiceField(queryset = models.NNewType.objects. all ()) # authors = form_model.ModelChoiceField(queryset=models.NNewType.objects.all()) |
自定义验证规则:
django的form十分强大,提供了自定义接口
1、基于对象的方法:
1 2 3 4 5 6 7 8 9 | from django.forms import Form from django.forms import widgets from django.forms import fields from django.core.validators import RegexValidator class MyForm(Form): user = fields.CharField( validators = [RegexValidator(r '^[0-9]+$' , '请输入数字' ), RegexValidator(r '^159[0-9]+$' , '数字必须以159开头' )], ) |
2、基于函数的验证
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 | import re from django.forms import Form from django.forms import widgets from django.forms import fields from django.core.exceptions import ValidationError # 自定义验证规则 def mobile_validate(value): mobile_re = re. compile (r '^(13[0-9]|15[012356789]|17[678]|18[0-9]|14[57])[0-9]{8}$' ) if not mobile_re.match(value): raise ValidationError( '手机号码格式错误' ) #raise抛出异常form就会捕获 class PublishForm(Form): title = fields.CharField(max_length = 20 , min_length = 5 , error_messages = { 'required' : '标题不能为空' , 'min_length' : '标题最少为5个字符' , 'max_length' : '标题最多为20个字符' }, widget = widgets.TextInput(attrs = { 'class' : "form-control" , 'placeholder' : '标题5-20个字符' })) # 使用自定义验证规则 phone = fields.CharField(validators = [mobile_validate, ], error_messages = { 'required' : '手机不能为空' }, widget = widgets.TextInput(attrs = { 'class' : "form-control" , 'placeholder' : u '手机号码' })) email = fields.EmailField(required = False , error_messages = { 'required' : u '邮箱不能为空' , 'invalid' : u '邮箱格式错误' }, widget = widgets.TextInput(attrs = { 'class' : "form-control" , 'placeholder' : u '邮箱' })) |
注:定义的phone字段,不要在phone函数里去处理其他字段的逻辑,因为有可能到phone的时候,还未添加到字典里,数值为空,会有异常
3、clean_字段名称 方法
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 | from django import forms from django.forms import fields from django.forms import widgets from django.core.exceptions import ValidationError from django.core.validators import RegexValidator class FInfo(forms.Form): username = fields.CharField(max_length = 5 , validators = [RegexValidator(r '^[0-9]+$' , 'Enter a valid extension.' , 'invalid' )], ) email = fields.EmailField() def clean_username( self ): """ Form中字段中定义的格式匹配完之后,执行此方法进行验证 :return: """ value = self .cleaned_data[ 'username' ] if "666" in value: raise ValidationError( '666已经被玩烂了...' , 'invalid' ) return value |
验证手机规则例子:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 | def clean_phone( self ): """ :return: 必须有返回值, """ # 去取用户提交的值:可能是错误的,可能是正确 value = self .cleaned_data[ 'phone' ] mobile_re = re. compile (r '^(13[0-9]|15[012356789]|17[678]|18[0-9]|14[57])[0-9]{8}$' ) if not mobile_re.match(value): raise ValidationError( '手机号码格式错误' ) if models.UserInfo.objects. filter (phone = value).count(): raise ValidationError( '手机号码已经存在' ) return value |
验证规则执行顺序:
第一个字段的正则,钩子函数(方法中只能取当前字段的值)
第二个字段的正则,钩子函数
整体验证: clean,必须有返回值, 给指定字段添加错误信息
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 | class RegisterForm(Form): name = fields.CharField() email = fields.EmailField() phone = fields.CharField() pwd = fields.CharField() pwd_confirm = fields.CharField() def clean( self ): pwd = self .cleaned_data[ 'pwd' ] pwd_confirm = self .cleaned_data[ 'pwd_confirm' ] if pwd = = pwd_confirm: return self .cleaned_data else : from django.core.exceptions import ValidationError # self.add_error('pwd', ValidationError('密码输入不一致')) self .add_error( 'pwd_confirm' , ValidationError( '密码输入不一致' )) return self .cleaned_data |
4、同时生成多个标签进行验证
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 | from django.forms import Form from django.forms import widgets from django.forms import fields from django.core.validators import RegexValidator ############## 自定义字段 ############## class PhoneField(fields.MultiValueField): def __init__( self , * args, * * kwargs): # Define one message for all fields. error_messages = { 'incomplete' : 'Enter a country calling code and a phone number.' , } # Or define a different message for each field. f = ( fields.CharField( error_messages = { 'incomplete' : 'Enter a country calling code.' }, validators = [ RegexValidator(r '^[0-9]+$' , 'Enter a valid country calling code.' ), ], ), fields.CharField( error_messages = { 'incomplete' : 'Enter a phone number.' }, validators = [RegexValidator(r '^[0-9]+$' , 'Enter a valid phone number.' )], ), fields.CharField( validators = [RegexValidator(r '^[0-9]+$' , 'Enter a valid extension.' )], required = False , ), ) super (PhoneField, self ).__init__(error_messages = error_messages, fields = f, require_all_fields = False , * args, * * kwargs) def compress( self , data_list): """ 当用户验证都通过后,该值返回给用户 :param data_list: :return: """ return data_list ############## 自定义插件 ############## class SplitPhoneWidget(widgets.MultiWidget): def __init__( self ): ws = ( widgets.TextInput(), widgets.TextInput(), widgets.TextInput(), ) super (SplitPhoneWidget, self ).__init__(ws) def decompress( self , value): """ 处理初始值,当初始值initial不是列表时,调用该方法 :param value: :return: """ if value: return value.split( ',' ) return [ None , None , None ] |
二、中间件middleware
Django本身就带middleware功能:
如下是django的生命周期
如下为中间件的执行顺序
- 中间件执行时机:请求到来,请求返回时
- 中间件是一个类:
def process_request(self,request):
print('m2.process_request')
def process_response(self,request, response):
print('m2.prcess_response')
return response
- 应用:
- 请求日志
- 用户登录认证
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 | #!/usr/bin/python # -*- coding:utf-8 -*- # from django.utils.deprecation import MiddlewareMixin from django.shortcuts import HttpResponse,redirect class MiddlewareMixin( object ): def __init__( self , get_response = None ): self .get_response = get_response super (MiddlewareMixin, self ).__init__() def __call__( self , request): response = None if hasattr ( self , 'process_request' ): response = self .process_request(request) if not response: response = self .get_response(request) if hasattr ( self , 'process_response' ): response = self .process_response(request, response) return response class m1(MiddlewareMixin): '''先执行request,然后到url路由,url之后返回到最上方,在执行view,如果出现错误就直接到response上,执行完,到真正到视图,如果有问题就 执行exception,从下至上查找,如果找到exception就直接执行exception的return在走response返回用户 每个中间件中,4个方法不需要都写. ''' # def process_request(self,request): #登录验证可以放在中间件里 # if request.path_info == '/userinfo/': # return None # if not request.session.get('user_info'): # return redirect('/userinfo/') def process_request( self ,request): print ( 'm1.process_request' ) def process_response( self ,request,response): print ( 'm1.process_response' ) return response def process_view( self ,request,callback,callback_args,callback_kwargs): print ( 'm1.process_view' ,callback) def process_exception( self ,request,exception): print ( 'm1.exception' ) class m2(MiddlewareMixin): def process_request( self ,request): print ( 'm2.process_request' ) def process_response( self ,request,response): print ( 'm2.process_response' ) return response def process_view( self ,request,callback,callback_args,callback_kwargs): print ( 'm2.process_view' ,callback) def process_exception( self ,request,exception): print ( 'm2.exception' ) return HttpResponse( '500 Error' ) |
注:新的django版本可能不存在MiddlewareMixin,需要手动写一下这个类进行继承
settings里配置:
1 2 3 4 5 6 7 8 9 10 11 | MIDDLEWARE = [ 'django.middleware.security.SecurityMiddleware' , 'django.contrib.sessions.middleware.SessionMiddleware' , 'django.middleware.common.CommonMiddleware' , 'django.middleware.csrf.CsrfViewMiddleware' , 'django.contrib.auth.middleware.AuthenticationMiddleware' , 'django.contrib.messages.middleware.MessageMiddleware' , 'django.middleware.clickjacking.XFrameOptionsMiddleware' , 'md.middleware.m1' , 'md.middleware.m2' , ] |
三、缓存
- 配置 - 开发调试 - 内存中 全局变量 - 文件中 - 数据库 - Memcached - 使用 - 全局 MIDDLEWARE = [ 'django.middleware.cache.UpdateCacheMiddleware', # 其他中间件 'django.middleware.cache.FetchFromCacheMiddleware', ] - 视图函数 from django.views.decorators.cache import cache_page @cache_page(10) def test1(request): import time ctime = time.time() return render(request,'test1.html',{'ctime':ctime}) - 局部模板 {% load cache %} <!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title>Title</title> </head> <body> <h1>TEST1 -> {{ ctime }}</h1> {% cache 10 "asdfasdfasdf" %} <h1>TEST1 -> {{ ctime }}</h1> {% endcache %} </body> </html>
由于Django是动态网站,所有每次请求均会去数据进行相应的操作,当程序访问量大时,耗时必然会更加明显,最简单解决方式是使用:缓存,缓存将一个某个views的返回值保存至内存或者memcache中,5分钟内再有人来访问时,则不再去执行view中的操作,而是直接从内存或者Redis中之前缓存的内容拿到,并返回。
1、配置
a、开发调试
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# 此为开始调试用,实际内部不做任何操作 # 配置: CACHES = { 'default': { 'BACKEND': 'django.core.cache.backends.dummy.DummyCache', # 引擎 'TIMEOUT': 300, # 缓存超时时间(默认300,None表示永不过期,0表示立即过期) 'OPTIONS':{ 'MAX_ENTRIES': 300, # 最大缓存个数(默认300) 'CULL_FREQUENCY': 3, # 缓存到达最大个数之后,剔除缓存个数的比例,即:1/CULL_FREQUENCY(默认3) }, 'KEY_PREFIX': '', # 缓存key的前缀(默认空) 'VERSION': 1, # 缓存key的版本(默认1) 'KEY_FUNCTION' 函数名 # 生成key的函数(默认函数会生成为:【前缀:版本:key】) } } # 自定义key def default_key_func(key, key_prefix, version): """ Default function to generate keys. Constructs the key used by all other methods. By default it prepends the `key_prefix'. KEY_FUNCTION can be used to specify an alternate function with custom key making behavior. """ return '%s:%s:%s' % (key_prefix, version, key) def get_key_func(key_func): """ Function to decide which key function to use. Defaults to ``default_key_func``. """ if key_func is not None: if callable(key_func): return key_func else: return import_string(key_func) return default_key_func
b、内存
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# 此缓存将内容保存至内存的变量中 # 配置: CACHES = { 'default': { 'BACKEND': 'django.core.cache.backends.locmem.LocMemCache', 'LOCATION': 'unique-snowflake', } } # 注:其他配置同开发调试版本
c、文件
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# 此缓存将内容保存至文件 # 配置: CACHES = { 'default': { 'BACKEND': 'django.core.cache.backends.filebased.FileBasedCache', 'LOCATION': '/var/tmp/django_cache', } } # 注:其他配置同开发调试版本
d、数据库
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# 此缓存将内容保存至数据库 # 配置: CACHES = { 'default': { 'BACKEND': 'django.core.cache.backends.db.DatabaseCache', 'LOCATION': 'my_cache_table', # 数据库表 } } # 注:执行创建表命令 python manage.py createcachetable
e、Memcache缓存(python-memcached模块)
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# 此缓存使用python-memcached模块连接memcache CACHES = { 'default': { 'BACKEND': 'django.core.cache.backends.memcached.MemcachedCache', 'LOCATION': '127.0.0.1:11211', } } CACHES = { 'default': { 'BACKEND': 'django.core.cache.backends.memcached.MemcachedCache', 'LOCATION': 'unix:/tmp/memcached.sock', } } CACHES = { 'default': { 'BACKEND': 'django.core.cache.backends.memcached.MemcachedCache', 'LOCATION': [ '172.19.26.240:11211', '172.19.26.242:11211', ] } }
f、Memcache缓存(pylibmc模块)
![](https://images.cnblogs.com/OutliningIndicators/ContractedBlock.gif)
# 此缓存使用pylibmc模块连接memcache CACHES = { 'default': { 'BACKEND': 'django.core.cache.backends.memcached.PyLibMCCache', 'LOCATION': '127.0.0.1:11211', } } CACHES = { 'default': { 'BACKEND': 'django.core.cache.backends.memcached.PyLibMCCache', 'LOCATION': '/tmp/memcached.sock', } } CACHES = { 'default': { 'BACKEND': 'django.core.cache.backends.memcached.PyLibMCCache', 'LOCATION': [ '172.19.26.240:11211', '172.19.26.242:11211', ] } }
h、redis的可以去网上找插件,pip install django-redis
![](https://images.cnblogs.com/OutliningIndicators/ContractedBlock.gif)
CACHES = { 'default': { 'BACKEND': 'redis_cache.cache.RedisCache', 'LOCATION': '127.0.0.1:6379', "OPTIONS": { "CLIENT_CLASS": "redis_cache.client.DefaultClient", }, }, } REDIS_TIMEOUT=7*24*60*60 CUBES_REDIS_TIMEOUT=60*60 NEVER_REDIS_TIMEOUT=365*24*60*60
2、应用
a、全站使用:
![](https://images.cnblogs.com/OutliningIndicators/ContractedBlock.gif)
使用中间件,经过一系列的认证等操作,如果内容在缓存中存在,则使用FetchFromCacheMiddleware获取内容并返回给用户,当返回给用户之前,判断缓存中是否已经存在,如果不存在则UpdateCacheMiddleware会将缓存保存至缓存,从而实现全站缓存 MIDDLEWARE = [ 'django.middleware.cache.UpdateCacheMiddleware', # 其他中间件... 'django.middleware.cache.FetchFromCacheMiddleware', ] CACHE_MIDDLEWARE_ALIAS = "" CACHE_MIDDLEWARE_SECONDS = "" CACHE_MIDDLEWARE_KEY_PREFIX = ""
b、单独视图缓存
![](https://images.cnblogs.com/OutliningIndicators/ContractedBlock.gif)
方式一: from django.views.decorators.cache import cache_page @cache_page(60 * 15) def my_view(request): ... 方式二: from django.views.decorators.cache import cache_page urlpatterns = [ url(r'^foo/([0-9]{1,2})/$', cache_page(60 * 15)(my_view)), ]
c、局部视图
![](https://images.cnblogs.com/OutliningIndicators/ContractedBlock.gif)
a. 引入TemplateTag {% load cache %} b. 使用缓存 {% cache 5000 缓存key %} 缓存内容 {% endcache %}
四、信号
1、应用场景,当遇比如要所有数据库在创建数据的时候,记录一条日志
Django中提供了“信号调度”,用于在框架执行操作时解耦。通俗来讲,就是一些动作发生的时候,信号允许特定的发送者去提醒一些接受者。
Django内置信号
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 | Model signals pre_init # django的modal执行其构造方法前,自动触发 post_init # django的modal执行其构造方法后,自动触发 pre_save # django的modal对象保存前,自动触发 post_save # django的modal对象保存后,自动触发 pre_delete # django的modal对象删除前,自动触发 post_delete # django的modal对象删除后,自动触发 m2m_changed # django的modal中使用m2m字段操作第三张表(add,remove,clear)前后,自动触发 class_prepared # 程序启动时,检测已注册的app中modal类,对于每一个类,自动触发 Management signals pre_migrate # 执行migrate命令前,自动触发 post_migrate # 执行migrate命令后,自动触发 Request / response signals request_started # 请求到来前,自动触发 request_finished # 请求结束后,自动触发 got_request_exception # 请求异常后,自动触发 Test signals setting_changed # 使用test测试修改配置文件时,自动触发 template_rendered # 使用test测试渲染模板时,自动触发 Database Wrappers connection_created # 创建数据库连接时,自动触发 |
对于Django内置的信号,仅需注册指定信号,当程序执行相应操作时,自动触发注册函数:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 | from django.core.signals import request_finished from django.core.signals import request_started from django.core.signals import got_request_exception from django.db.models.signals import class_prepared from django.db.models.signals import pre_init, post_init from django.db.models.signals import pre_save, post_save from django.db.models.signals import pre_delete, post_delete from django.db.models.signals import m2m_changed from django.db.models.signals import pre_migrate, post_migrate from django.test.signals import setting_changed from django.test.signals import template_rendered from django.db.backends.signals import connection_created def callback(sender, * * kwargs): print ( "xxoo_callback" ) print (sender,kwargs) xxoo.connect(callback) # xxoo指上述导入的内容 |
views里写法:
1 2 3 4 5 6 | from django.core.signals import request_finished from django.dispatch import receiver @receiver (request_finished) def my_callback(sender, * * kwargs): print ( "Request finished!" ) |
2、自定义信号
a、定义信号
1 2 | import django.dispatch pizza_done = django.dispatch.Signal(providing_args = [ "toppings" , "size" ]) |
b、注册信号
1 2 3 4 5 | def callback(sender, * * kwargs): print ( "callback" ) print (sender,kwargs) pizza_done.connect(callback) |
c、触发信号:
1 2 3 | from 路径 import pizza_done pizza_done.send(sender = 'seven' ,toppings = 123 , size = 456 ) |
五、Admin后台
http://www.cnblogs.com/liujiliang/p/7580715.html
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