request请求生命周期

一、request请求分析

1.1. request数据请求

# views.py

from rest_framework.views import APIView

from rest_framework.response import Response

from django.http.request import QueryDict

class BookAPIView(APIView):

    def get(self, request, *args, **kwargs):

        print(request._request.GET)  # 原生wigs中值

        print(request.GET) # 二次封装的值

        print(request.META) # 所有get请求信息

        print(request.META.get("HTTP_AUTH")) # 前台发来的头都会大写并加上HTTP

        print(request.query_params) # 所有url数据

        print(request.POST) # get请求不能获取Post请求数据

        return Response('get ok')

    def post(self, request, *args, **kwargs):

        print(request._request.POST)  # 原生wigs中值

        print(request.POST) # 二次封装的值

        print(request.data) # 所有post请求数据

        print(request._request) # url数据包<WSGIRequest: POST '/books/?age=123'>

        print(request.GET) # POST请求可以Post请求数据

         # QueryDict转为

        print(request.query_params.dict())

        if isinstance(request.data, QueryDict):

            print(request.data.dict())

        return Response('post ok')

# urls.py

from . import views

urlpatterns = [

    url(r'^books/$', views.BookAPIView.as_view()),

]

request请求生命周期

总结：

drf中的request是在wsgi的request基础上进行再一次封装
将wsgi的request作为drf的request的一个属性, _request
drf中的request对wsgi中的request做完全兼容，新的可以直接获取wsgi中的数据
drf中的request对数据解析更规范化,所有的拼接参数(url?age=18)都解析到了query_params中，所有数据报数据都解析到data中
query_params和data属于QueryDict类型,可以通过.dict()转化为字典类型

二、request请求源码分析

# 1. 2. urls.py

from . import views

urlpatterns = [

    url(r'^books/$', views.BookAPIView.as_view()),

]

#3.调用drf中的as_view

@classmethod

def as_view(cls, **initkwargs):     # cls 为 views.BookAPIView类

    ...

    view = super().as_view(**initkwargs) # as_view原生的as_view,super() 为 view

    view.cls = cls

    view.initkwargs = initkwargs

    return csrf_exempt(view)

# 4.进入drf中dispatch

def dispatch(self, request, *args, **kwargs):   # self为views.BookAPIView类

    self.args = args

    self.kwargs = kwargs

    # 对原生request进行了二次封装

    request = self.initialize_request(request, *args, **kwargs)

    self.request = request

    self.headers = self.default_response_headers  # deprecate?

    try:

        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

# 4.1 返回封装的request对象

def initialize_request(self, request, *args, **kwargs):

    """

        Returns the initial request object.

        """

    parser_context = self.get_parser_context(request) # 解析

    return Request(

        request, # 二次封装

        parsers=self.get_parsers(),

        authenticators=self.get_authenticators(),

        negotiator=self.get_content_negotiator(),

        parser_context=parser_context

    )

# 5.Request类创建 self._request = request自己的属性

 def __init__(self, request, parsers=None, authenticators=None,

                 negotiator=None, parser_context=None):

        assert isinstance(request, HttpRequest), (

            .format(request.__class__.__module__, request.__class__.__name__)

        )

        self._request = request

        self.parsers = parsers or ()

        self.authenticators = authenticators or ()

        self.negotiator = negotiator or self._default_negotiator()

        self.parser_context = parser_context

#6.如何实现获取wgis中的属性

def __getattr__(self, attr):

    """

        If an attribute does not exist on this instance, then we also attempt

        to proxy it to the underlying HttpRequest object.

        """

    try:

        return getattr(self._request, attr)

    except AttributeError:

        return self.__getattribute__(attr)

request请求生命周期

导入drf中的APIView并创建类继承它，在配置url: url(r'^books/$', views.BookAPIView.as_view()),
当项目启动时会执行drf中的as_view()方法，返回view方法(局部禁用了csrf认证)， url：url(r'^books/$', views.BookAPIView.view
浏览器发送请求来时则会执行url中view函数，在执行view中返回的是 self.dispatch(request, *args, **kwargs), dispatch是drf中的dispatch, 不是wsgi中原生的dispatch
进入drf中的dispatch首先会对原生的request进行二次封装：request = self.initialize_request(request, *args, **kwargs),在initialize_request方法中返回了一个request实例对象
进入request.py中的Request方法中就会发现在初始化方法中将wsgi方法的request变为了自己的一个属性： 'self._request = request'

request通过反射的方法获取wsgi中request属性，当request.获取属性先到 _request中查找，没有则查自己本身的

#6.如何实现获取wgis中的属性

def __getattr__(self, attr):

    """

        If an attribute does not exist on this instance, then we also attempt

        to proxy it to the underlying HttpRequest object.

        """

    try:

        return getattr(self._request, attr)

    except AttributeError:

        return self.__getattribute__(attr)

核心
- 走drf的Request初始化方法__init__：self._request = request
- drf的Request的getter方法__getattr__：先从self._request反射取属性，没取到再从drf的request中取
- request除了可以访问原wsgi协议的request所有内容，还可以访问 query_params、data

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request请求生命周期

request请求生命周期

一、request请求分析

二、request请求源码分析

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