Django-djangorestframework-请求模块-获取请求参数

suwanbin

发布于 2019-12-12 14:40:30

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发布于 2019-12-12 14:40:30

文章被收录于专栏：小码农漫漫积累路

请求模块

主要是分析 drf 二次封装后的 request 对象以及怎么拿到请求传递过来的数据（url 拼接的数据，数据包传过来的数据）

源码分析

源码查看，从 as_view 进到 APIView 类的 dispatch 方法，dispatch 中的 request = self.initialize_request(request, *args, **kwargs) 中入手

rest_framework.views.APIView#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
        # 请求模块
        request = self.initialize_request(request, *args, **kwargs)
        self.request = request
        self.headers = self.default_response_headers  # deprecate?

        try:
            # 三大认证模块
            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

rest_framework.views.APIView#initialize_request

    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(),
            authenticators=self.get_authenticators(),
            negotiator=self.get_content_negotiator(),
            parser_context=parser_context
        )

rest_framework.request.Request#__init__

    def __init__(self, request, parsers=None, authenticators=None,
                 negotiator=None, parser_context=None):
        assert isinstance(request, HttpRequest), (
            'The `request` argument must be an instance of '
            '`django.http.HttpRequest`, not `{}.{}`.'
            .format(request.__class__.__module__, request.__class__.__name__)
        )
        # 二次封装 request，将原生 request 作为 drf request 对象的 _request 属性
        self._request = request
        # 虽然 drf 对 request 对象做了二次封装，但是它也做了完全兼容（见下面的 __getattr__ 方法）
        
        self.parsers = parsers or ()
        self.authenticators = authenticators or ()
        self.negotiator = negotiator or self._default_negotiator()
        self.parser_context = parser_context
        self._data = Empty
        self._files = Empty
        self._full_data = Empty
        self._content_type = Empty
        self._stream = Empty

        if self.parser_context is None:
            self.parser_context = {}
        self.parser_context['request'] = self
        self.parser_context['encoding'] = request.encoding or settings.DEFAULT_CHARSET

        force_user = getattr(request, '_force_auth_user', None)
        force_token = getattr(request, '_force_auth_token', None)
        if force_user is not None or force_token is not None:
            forced_auth = ForcedAuthentication(force_user, force_token)
            self.authenticators = (forced_auth,)

rest_framework.request.Request#__getattr__ 做了特殊兼容

    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:
            # 对原有的 request 做了完全兼容
            return getattr(self._request, attr)
        except AttributeError:
            return self.__getattribute__(attr)

正式使用

--> 所以在 APIView 视图类的方法中我们可以这样写

所以以后

url 拼接的参数都可以用 request.query_params 来取
所有请求的数据包方式数据都可以用 request.data 来取，所有数据方式（from-data、json...）它都做解析了

class Test(APIView):
    def get(self, request, *args, **kwargs):
        # 获取 url 拼接的参数
        print(request._request.GET)  # 二次封装
        print(request.GET)  # 兼容
        print(request.query_params)  # 扩展，推荐用这个
        
        return Response("drf get ok.")
        
    def post(self, request, *args, **kwargs):
        # 获取 url 拼接的参数 (所有请求方式都可以携带这个)
        print(request._request.GET)
        print(request.GET)  # 兼容
        print(request.query_params)  # 扩展，推荐用这个
        
        # 获取 post 参数
        print(request._request.POST)  # 拿不到 json 的数据 
        print(request.POST)  # 兼容，拿不到 json 的数据
        print(request.data)  # 扩展，兼容性最强，三种数据方式都可以，推荐用这个
        
        return Response("drf post ok")