Python篇-Django进阶篇

2018-03-12 本文已影响154人 TianTianBaby223

一 : CSRF验证

为了防止模拟跨站访问的CSRF攻击,Django里中间件通常会设置一个django.middleware.csrf.CsrfViewMiddleware 来确保此次访问是用户行为,本地生成随机字符串,并且放入cookie中,假如再次提交时候没有此随机字符串则无法通过

templates处理
在form表单中放入{% csrf_token %}

<form action="/myapp/sessionLogin" method="POST">
        {% csrf_token %}
     
        <input id="btn" type="button" value="按钮"/>

   
    </form>

template Ajax处理

<script>
            $(function () {

#全局作用域
                $.ajaxSetup({
                    beforeSend:function (xhr,settings) {
                        xhr.setRequestHeader('X-CSRFtoken',$.cookie('csrftoken'));
                    }
                });
#按钮点击事件
                $('#btn').click(function () {
                    $.ajax({
                        url:'/myapp/sessionLogin',
                        type:"POST",
                        data:{
                            'user':'tz111',
                            'pwd':'123',
                            suceess:function (arg) {

                            }
                        }
                    })
                })
            })

        </script>

局部添加/取消

@csrf_protect，为当前函数强制设置防跨站请求伪造功能，即便settings中没有设置全局中间件。

@csrf_exempt，取消当前函数防跨站请求伪造功能，即便settings中设置了全局中间件。

二 : 中间件

在Django的请求周期中中间件好像一层过滤网,网这个View添加或者屏蔽功能

流程图

过程解析
当请求发出时候->经过precess_request->进行路由分发,函数匹配到相关url 则进行process_view否则请求失败->函数(viewfunction)处理完毕->经过precess_response返回数据层层返回->假如有异常则执行process_exception
实例
用自定义中间件模拟请求,观察流程
创造自定义中间件

rom django.utils.deprecation import MiddlewareMixin
from django.shortcuts import HttpResponse

class first(MiddlewareMixin):
    def process_request(self,request):
        print('雪芙')

    def process_view(self,request,view_func,view_func_args,view_fun_kwargs):
        print('n1')

    def process_response(self,request,response):
        print('1')
        return response


class second(MiddlewareMixin):
    def process_request(self,request):

        print('曼丽')
        # return HttpResponse('NO')

    def process_view(self,request,view_func,view_func_args,view_fun_kwargs):
        print('n2')

    def process_response(self,request,response):
        print('2')
        return  response



class third(MiddlewareMixin):
    def process_request(self,request):
        print('梦瑶')


    def process_view(self,request,view_func,view_func_args,view_fun_kwargs):
        print('n3')

    def process_response(self,request,response):
        print('3')
        return response

    # View如果出错 执行
    def process_exception(self, request, exception):
        if isinstance(exception, ValueError):
            print('4454545545楚翔')
            return HttpResponse('出现异常')
        print('ex')


    #如果View中的函数返回的对象中,具有render方法
    def process_template_response(self,request,response):
        print('--------------')
        return response

setting配置中间件

MIDDLEWARE = [
...
    'TZmiddle.m1.first',
    'TZmiddle.m1.second',
    'TZmiddle.m1.third',
...
]

执行结果

执行结果

三 : 缓存

配置：
5 种配置
实例
3种应用 :全局视图函数模板

全局:

MIDDLEWARE = [
    # 'django.middleware.cache.UpdateCacheMiddleware',
        ...
        ...
    # 'django.middleware.cache.FetchFromCacheMiddleware',

]

setting设置

CACHES = {
    'default': {
        'BACKEND': 'django.core.cache.backends.filebased.FileBasedCache',
        'LOCATION': os.path.join(BASE_DIR,'cache')
    }
}

View

from django.views.decorators.cache import cache_page

@cache_page(20)
def cache(request):
    ctime = time.time()
    return render(request,'cache.html',{'ctime':ctime})

templates

{% load cache %}
<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>cache</title>
</head>
<body>
    {{ ctime }}
    {{ ctime }}

    {% cache 10 c1 %}
        {{ ctime }}
    {% endcache %}

</body>
</html>

四 : 信号

官方解释:Django includes a “signal dispatcher” which helps allow decoupled applications get notified when actions occur elsewhere in the framework.In a nutshell, signals allow certain senders to notify a set of receivers that some action has taken place. They’re especially useful when many pieces of code may be interested in the same events.

Django内部包含了一位“信号调度员”：当某事件在框架内发生时，它可以通知到我们的应用程序。简而言之，当event（事件）发生时，signals（信号）允许若干 senders（寄件人）通知一组 receivers（接收者）。这在我们多个独立的应用代码对同一事件的发生都感兴趣时，特别有用。

自定义信号实例View部分

def signal(request):
    from  sg import pizza_done
    pizza_done.send(sender="tz",topping =11111,size = 456)
    return HttpResponse('ok')

信号Py

from django.db.models.signals import pre_init,post_init
import django.dispatch
pizza_done = django.dispatch.Signal(providing_args=["toppings","size"])

def callback(sender,**kwargs):
    print("callback")
    print(sender,kwargs)
pizza_done.connect(callback)

五 : form组件验证

django中的Form可以进行用户验证 ,也可以生成响应页面,功能十分强大.

实例View部分

from  django import forms
from django.forms import widgets
from django.forms import fields
class FM(forms.Form):
    user = fields.CharField(
        error_messages={'required': '用户名不能为空.'},
        widget=widgets.Textarea(attrs={'class': 'c1'}),
        label="用户名",
        # 初始值
        # initial='root',
                           )
    pwd = fields.CharField(max_length=12,
                           min_length=6,
                           error_messages={'required':'密码不能为空',"min_length":"密码长度不能小于6","max_length":"密码长度不能大于12"},
                           widget = widgets.PasswordInput,

                           )
    email = fields.EmailField(error_messages={'required':'邮箱不能为空','invalid':"邮箱格式错误"})

    # f = fields.FileField()
    p = fields.FilePathField(path='myapp')

    city1 = fields.ChoiceField(

        choices=[{0,'欧洲'},{1,'美洲'},{2,'沈阳'},{3,'大连'}]

    )

    city2 = fields.MultipleChoiceField(

        choices=[{0, '欧洲'}, {1, '美洲'}, {2, '沈阳'}, {3, '大连'}]

    )


def fm(request):
    if request.method == 'GET':
        #从数据库红把数据获取到
        dic = {
            "user":'tz',
            "pwd":'123123',
            "email":'54544@qq.com,
            "city":1,
            'city2':[1,2]

        }

        obj = FM(initial=dic)
        return render(request,'fm.html',{'obj':obj})

    elif request.method =="POST":
        obj = FM(request.POST)
        r1 = obj.is_valid()
        if r1:
            print(obj.cleaned_data)

            #注册
            # models.UserInfo.objects.creat(**obj.cleaned_data)
        else:
            print(obj.errors.as_json())
            return render(request, 'fm.html',{'obj':obj})
        return render(request, 'fm.html')

实例tempaltes部分

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>fm</title>
</head>
<body>
    <form action="/myapp/fm" method="POST">
        {% csrf_token %}
        <p>{{ obj.user.label }}{{ obj.user }}{{ obj.errors.user.0 }} </p>
        <p>{{ obj.pwd }}{{ obj.errors.pwd.0 }}</p>
        <p>{{ obj.email }}{{ obj.errors.email.0 }}</p>
        <P>{{ obj.f }}{{ obj.errors.f.0 }}</P>
        {{ obj.city1 }}
        {{ obj.city2 }}
        <input type="submit" value="提交"/>
    </form>

</body>
</html>