Django rest_framework（DRF），学完之后，明显感觉自己对于Django的认知又拔高了一个level。
具体体现在以下几个方面，对于整个web开发的流程有了完整的认识，对于django各个组件以及组件之间的结合有了更深的体会。
DRF的关键就在于一个点上——APIView类下面的dispatch方法
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 # 1）对原生request进行了封装 request = self.initialize_request(request, *args, **kwargs) self.request = request self.headers = self.default_response_headers # deprecate? try: # 2）对前端的请求增加的3个限制，认证、权限、频率 self.initial(request, *args, **kwargs) # Get the appropriate handler method if request.method.lower() in self.http_method_names: # 3）通过反射执行“get/post/put/delete”函数 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) # 4）将返回的数据封装进自己提供的页面中 self.response = self.finalize_response(request, response, *args, **kwargs) return self.response <wiz_code_mirror>
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def dispatch(self, request, *args, **kwargs):
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"""
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`.dispatch()` is pretty much the same as Django's regular dispatch,
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but with extra hooks for startup, finalize, and exception handling.
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"""
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self.args = args
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self.kwargs = kwargs
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# 1）对原生request进行了封装
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request = self.initialize_request(request, *args, **kwargs)
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self.request = request
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self.headers = self.default_response_headers # deprecate?
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try:
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# 2）对前端的请求增加的3个限制，认证、权限、频率
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self.initial(request, *args, **kwargs)
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# Get the appropriate handler method
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if request.method.lower() in self.http_method_names:
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# 3）通过反射执行“get/post/put/delete”函数
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handler = getattr(self, request.method.lower(),
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self.http_method_not_allowed)
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else:
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handler = self.http_method_not_allowed
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response = handler(request, *args, **kwargs)
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except Exception as exc:
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response = self.handle_exception(exc)
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# 4）将返回的数据封装进自己提供的页面中
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self.response = self.finalize_response(request, response, *args, **kwargs)
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return self.response
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1）先看看对request做了那些操作
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(), # 首先获取到解析器，限制前端数据的请求与发送方式 authenticators=self.get_authenticators(), # 获取认证信息 negotiator=self.get_content_negotiator(), # 获取默认的异常处理信息 parser_context=parser_context # 对应上面的，如果数据解析通过，将数据打包成字典供view用 )<wiz_code_mirror>
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def initialize_request(self, request, *args, **kwargs):
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"""
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Returns the initial request object.
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"""
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parser_context = self.get_parser_context(request)
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return Request(
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request,
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parsers=self.get_parsers(), # 首先获取到解析器，限制前端数据的请求与发送方式
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authenticators=self.get_authenticators(), # 获取认证信息
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negotiator=self.get_content_negotiator(), # 获取默认的异常处理信息
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parser_context=parser_context # 对应上面的，如果数据解析通过，将数据打包成字典供view用
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)
结论：从Request（）类中的参数就可以看出Request（）类在实例化的过程会对request中的数据进行认证、解析等限制。DRF的解析组件、认证组件的功能就用在了这里！此外还做了什么其实通过Request（）类中的属性和方法就已经能知道个所以然了！
2）紧接着又做了3个限制。（认证、权限、频率的调用）
def initial(self, request, *args, **kwargs): """ Runs anything that needs to occur prior to calling the method handler. """ self.format_kwarg = self.get_format_suffix(**kwargs) # Perform content negotiation and store the accepted info on the request neg = self.perform_content_negotiation(request) request.accepted_renderer, request.accepted_media_type = neg # Determine the API version, if versioning is in use. # 如果使用版本控制，则确定API版本。 version, scheme = self.determine_version(request, *args, **kwargs) request.version, request.versioning_scheme = version, scheme # Ensure that the incoming request is permitted # 三个限制组件在这里执行 self.perform_authentication(request) self.check_permissions(request) self.check_throttles(request)<wiz_code_mirror>
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def initial(self, request, *args, **kwargs):
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"""
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Runs anything that needs to occur prior to calling the method handler.
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"""
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self.format_kwarg = self.get_format_suffix(**kwargs)
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# Perform content negotiation and store the accepted info on the request
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neg = self.perform_content_negotiation(request)
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request.accepted_renderer, request.accepted_media_type = neg
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# Determine the API version, if versioning is in use.
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# 如果使用版本控制，则确定API版本。
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version, scheme = self.determine_version(request, *args, **kwargs)
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request.version, request.versioning_scheme = version, scheme
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# Ensure that the incoming request is permitted
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# 三个限制组件在这里执行
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self.perform_authentication(request)
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self.check_permissions(request)
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self.check_throttles(request)
def perform_authentication(self, request): """ Perform authentication on the incoming request. Note that if you override this and simply 'pass', then authentication will instead be performed lazily, the first time either `request.user` or `request.auth` is accessed. """ request.user # 这个地方不要懵逼了，其实是执行Request（）里面的user（）方法<wiz_code_mirror>
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def perform_authentication(self, request):
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"""
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Perform authentication on the incoming request.
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Note that if you override this and simply 'pass', then authentication
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will instead be performed lazily, the first time either
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`request.user` or `request.auth` is accessed.
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"""
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request.user # 这个地方不要懵逼了，其实是执行Request（）里面的user（）方法
回到Request（）类中来
其他的三个都一样的，没啥好说的了！
3）执行序列化组件了，分发路由，没啥好说的！
4）最后调用Responce响应器。就是返回DRF为我们提供的一个响应页面！
总结：
dispatch( )的执行其实就把DRF提供的十个组件轮一遍的过程，也就是对于前端的请求进行了限制、加工到做出响应的过程！
DRF源码展现了python类的封装、继承、派生、等有意思的玩法，里面有大量的python风格的代码！读明白之后会觉得非常有乐趣！