Django 2.0 Middleware的写法

网上很多写法，都是传统的写法，

process_request和process_response方法，还可以用，但process_view的执行流程已经不行了。

看了官方文档，推荐的写法，也是用__call__方法来作实现了。

我试了新老方法，从输出，可以看出效果了。

中间件处理的顺序还是request从上到下，response从下回到上的。

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

class Row1(MiddlewareMixin):
    def __init__(self, get_response):
        self.get_response = get_response
        # One-time configuration and initialization.

    def process_request(self, request):
        print('中间件1的请求')

    def process_response(self, request, response):
        print('中间件1的返回')
        return response

    def __call__(self, request):
        # Code to be executed for each request before
        # the view (and later middleware) are called.

        print('中间件1的 view前调用')
        response = self.get_response(request)

        # Code to be executed for each request before
        # the view (and later middleware) are called.

        print('中间件1的 view之后调用')

        return response

class Row2(MiddlewareMixin):
    def __init__(self, get_response):
        self.get_response = get_response
        # One-time configuration and initialization.

    def process_request(self, request):
        print('中间件2的请求')
        # return HttpResponse('前端显示：中间件：M2.process_request')

    def process_response(self, request, response):
        print('中间件2的返回')
        return response

    def __call__(self, request):
        # Code to be executed for each request before
        # the view (and later middleware) are called.

        print('中间件2的 view前调用')
        response = self.get_response(request)

        # Code to be executed for each request before
        # the view (and later middleware) are called.

        print('中间件2的 view之后调用')

        return response

class Row3(MiddlewareMixin):
    def __init__(self, get_response):
        self.get_response = get_response
        # One-time configuration and initialization.

    def process_request(self, request):
        print('中间件3的请求')

    def process_response(self, request, response):
        print('中间件3的返回')
        return response

    def process_view(self, request, callback, callback_args, callback_kwargs):
        print('中间件3的 view')

settings.py里的排列：

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',
    'Middle.cm1.Row1',
    'Middle.cm1.Row2',
    'Middle.cm1.Row3',
]

输出，注意Row3里process_view输出没有反应，

而Row1和Row2的process_request, process_rewponse的输出被忽略。

Quit the server with CTRL-BREAK.
中间件1的 view前调用
中间件2的 view前调用
中间件3的请求
中间件3的返回
中间件2的 view之后调用
中间件1的 view之后调用
[03/Jan/2019 20:08:58] "GET / HTTP/1.1" 200 16348