中間件是介於request與response處理之間的一道處理過程，在全局上改變django的輸入與輸出

Django默認的Middleware：

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‘,
]
 

當用戶發起請求的時候會依次經過所有的的中間件，這個時候的請求為process_request,最後到達views的函數中，views函數處理後，再依次穿過中間件，這個時候是process_response,最後返回給請求者

自定義中間件：

首先需要自己創建一個py文件，包含自定義的Middleware類（繼承MiddlewareMixin）

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


class CustomerMiddleware(MiddlewareMixin):

    def process_request(self, request):
        print(‘CustomerMiddleware process_request...‘)
        # return HttpResponse(‘<h1>forbidden</h1>‘)

    def process_response(self, request, response):
        print(‘CustomerMiddleware process_response...‘)
        print(‘request:‘, request)
        print(‘response:‘, response)
        return response

    def process_view(self, request, callback, callback_args, callback_kwargs):
        print(‘CustomerMiddleware process_view‘)
        print(‘callback(視圖函數):‘, callback)

    def process_exception(self, request, exception):
        print(‘CustomerMiddleware process_exception‘)


class CustomerMiddleware2(MiddlewareMixin):

    def process_request(self, request):
        print(‘CustomerMiddleware2 process_request...‘)

    def process_response(self, request, response):
        print(‘CustomerMiddleware2 process_response...‘)
        print(‘request:‘, request)
        print(‘response:‘, response)
        return response

    def process_view(self, request, callback, callback_args, callback_kwargs):
        print(‘CustomerMiddleware2 process_view‘)

    def process_exception(self, request, exception):
        print(‘CustomerMiddleware2 process_exception‘)
        return HttpResponse(‘<h3>Error:%s</h3>‘ % exception)

 

在settings.py配置自定義的中間件：

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‘,
    
    ‘app01.MyMiddleware.CustomerMiddleware‘,
    ‘app01.MyMiddleware.CustomerMiddleware2‘,
]
 

運行結果：

CustomerMiddleware process_request...
CustomerMiddleware2 process_request...
CustomerMiddleware process_view
callback(視圖函數): <function index at 0x0471F3D8>
CustomerMiddleware2 process_view
view...
CustomerMiddleware2 process_response...
request: <WSGIRequest: GET ‘/index/‘>
response: <HttpResponse status_code=200, "text/html; charset=utf-8">
CustomerMiddleware process_response...
request: <WSGIRequest: GET ‘/index/‘>
response: <HttpResponse status_code=200, "text/html; charset=utf-8">

中間件包含這四種方法：

process_request  # 請求接收請求數據
process_view  # process_request執行後，依次執行process_view，最後調用視圖函數，如果有返回值，會越過其他的process_view以及視圖函數，但是所有的process_response都還會執行。
process_exception  #  在視圖函數執行出錯的時候才會執行該方法
process_response  # 用於返回數據

【Django】中間件