Django rest framework(5) ---解析器

（1）api/urls.py

# api/urls.py

from django.urls import path,re_path
from .views import UserView,PaserView

urlpatterns = [
    re_path('(?P<version>[v1|v2]+)/users/', UserView.as_view(),name = 'api_user'),
    path('paser/', PaserView.as_view(),),   #解析
]

（2）views.py

from rest_framework.parsers import JSONParser,FormParser

class PaserView(APIView):

    parser_classes = [JSONParser,FormParser,]
    #JSONParser：表示只能解析content-type:application/json的头
    #FormParser:表示只能解析content-type:application/x-www-form-urlencoded的头

    def post(self,request,*args,**kwargs):
        #获取解析后的结果
        print(request.data)
        return HttpResponse('paser')

（3）通过postman发送Json数据

 在后台可以获取发过来的Json数据

源码流程

 （1）dispatch

    def dispatch(self, request, *args, **kwargs):
        """
        `.dispatch()` is pretty much the same as Django's regular dispatch,
        but with extra hooks for startup, finalize, and exception handling.
        """
        self.args = args
        self.kwargs = kwargs
        #对原始request进行加工，丰富了一些功能
        #Request(
        #     request,
        #     parsers=self.get_parsers(),
        #     authenticators=self.get_authenticators(),
        #     negotiator=self.get_content_negotiator(),
        #     parser_context=parser_context
        # )
        #request(原始request,[BasicAuthentications对象，])
        #获取原生request,request._request
        #获取认证类的对象，request.authticators
        #1.封装request
        request = self.initialize_request(request, *args, **kwargs)
        self.request = request
        self.headers = self.default_response_headers  # deprecate?

        try:
            #2.认证
            self.initial(request, *args, **kwargs)

            # Get the appropriate handler method
            if request.method.lower() in self.http_method_names:
                handler = getattr(self, request.method.lower(),
                                  self.http_method_not_allowed)
            else:
                handler = self.http_method_not_allowed

            response = handler(request, *args, **kwargs)

        except Exception as exc:
            response = self.handle_exception(exc)

        self.response = self.finalize_response(request, response, *args, **kwargs)
        return self.response

（2）initialize_request

获取所有解析器

 def initialize_request(self, request, *args, **kwargs):
        """
        Returns the initial request object.
        """
        parser_context = self.get_parser_context(request)

        return Request(
            request,
            parsers=self.get_parsers(),                  #获取所有的解析器
            authenticators=self.get_authenticators(),    #[BasicAuthentication(),],把所有的认证类对象封装到request里面了
            negotiator=self.get_content_negotiator(),
            parser_context=parser_context
        )

（3）get_parsers

    def get_parsers(self):
        """
        Instantiates and returns the list of parsers that this view can use.
        """
        return [parser() for parser in self.parser_classes]

（4）parser_classes

 同样我们可以在settings里面全局配置

#全局配置
REST_FRAMEWORK = {
    #版本
    "DEFAULT_VERSIONING_CLASS":"rest_framework.versioning.URLPathVersioning",   
    #解析器
    "DEFAULT_PARSER_CLASSES":["rest_framework.parsers.JSONParser","rest_framework.parsers.FormParser"]
}