middleware

Posted 2020-10-07 dragonbird

自定义middleware

新建一个文件夹，里面写自己的middleware

在settings 设置，

 

在middleware.py文件中导入

 

from django.utils.deprecation import MiddlewareMixin


如果没法导入
可以这么写

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

以上这段代码用到了责任连模式和类似递归的思想

自己写个代码模仿django 工作机制

class Md(object):
    def __init__(self,get_response=None):
        self.get_response = get_response
    
    def __call__(self,request):
        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 Md1(Md):
    def process_request(self,request):
        print(\'request>>>md1\')
    def process_response(self,request,response):
        response.name=\'yuyang\'
        print(\'response<<<<<md1\')
        return response

class Md2(Md):
    def process_request(self,request):
        print(\'request>>>md2\')
        # return Response()
    def process_response(self,request,response):
        response.age=\'12\'
        print(\'response<<<<<md2\')
        return response

class Md3(Md):
    def process_request(self,request):
        print(\'request>>>md3\')
    def process_response(self,request,response):
        response.gender=\'male\'
        print(\'response<<<<<md3\')
        return response

class Request(object):
    def __init__(self):
        self.name = \'request\'

request_obj = Request()
class Response(object):
    def __init__(self):
        self.body=\'hello world\'
    pass

#  实例化

def view(request):
    print(\'>>>>>>>>view function <<<<<<<<<<\')
    return Response()

md3_obj = Md3(view)
md2_obj = Md2(md3_obj)
md1_obj = Md1(md2_obj)
res = md1_obj(request_obj)
print(res.__dict__)

 

 

 

 

 

class M1(MiddlewareMixin):
    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, view_func, view_func_args, view_func_kwargs):
        print(\'m1.process_view\')
        return render(request, \'login.html\')

class M2(MiddlewareMixin):
    def process_request(self, request):
        print(\'m2.process_request\')

    def process_view(self, request, view_func, view_func_args, view_func_kwargs):
        print(\'M2.process_view\')
        # return render(request, \'login.html\')

    def process_exception(self, request, exception):
        print(\'m2.process_exception\')
        return HttpResponse(\'开发的程序员已经被打死\')

    def process_response(self, request, response):
        print(\'m2.process_response\')
        return response

    def process_template_response(self, request, response):
        print(\'m2.process_template_response\')
        return response

 

5个方法：
process_request
process_response

process_exception

process_template_respons

process_view(self, request, view_func, view_func_args, view_func_kwargs)

process_response 是要有返回值的，
关于执行的顺序，

 

在上面这个列表中，当http请求到来，request会依次经过app01.md.M1，......django.middleware.clickjacking.XFrameOptionsMiddleware
response  正好相反
note: