下面的代码都是我从github上下载的源码中摘取的
django: https://github.com/django/django
下载命令： git clone https://github.com/django/django.git
rest_framework: https://github.com/tomchristie/django-rest-framework
下载命令： git clone https://github.com/tomchristie/django-rest-framework.git
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（1）as_view()是什么意思？为什么要加这个。 下面这段话是我从晚上摘录的 ========================================================== 因为 URLConf 仍然使用“给一个可调用对象传入 HttpRequest ，并期待其返回一个 HttpResponse”这样的逻辑，所以对于类视图，必须设计一个可调用的接口。这就是类视图的 as_view() 类方法。他接受 request，并实例化类视图，接着调用实例的 dispatch() 方法。这个方法会依据 request 的请求类型再去调用实例的对应同名方法，并把 request 传过去，如果没有对应的方法，就引发一个 HttpResponseNotAllowed 异常。 ========================================================== 我的理解： views.py里面定义的类继承了rest_framework/views.py的class APIView(VIew)类，这个类里面有一个 def as_view(clas, **initkwargs)这个函数。结合上面的叙述就可以知道了。 我在源码里面找了一下，调研了一下。 1 rest_framework/views.py 2 3 @classmethod 4 def as_view(cls, **initkwargs): 5 """ 6 Store the original class on the view function. 7 8 This allows us to discover information about the view when we do URL 9 reverse lookups. Used for breadcrumb generation. 10 """ 11 view = super(APIView, cls).as_view(**initkwargs) 12 view.cls = cls 13 # Note: session based authentication is explicitly CSRF validated, 14 # all other authentication is CSRF exempt. 15 return csrf_exempt(view) 16 17 ======================================================================= 18 django/views/decorators/csrf.py 19 20 def csrf_exempt(view_func): 21 """ 22 Marks a view function as being exempt from the CSRF view protection. 23 """ 24 # We could just do view_func.csrf_exempt = True, but decorators 25 # are nicer if they don't have side-effects, so we return a new 26 # function. 27 def wrapped_view(*args, **kwargs): 28 return view_func(*args, **kwargs) 29 wrapped_view.csrf_exempt = True 30 return wraps(view_func, assigned=available_attrs(view_func))(wrapped_view) 31 ======================================================================= 32 python27/Lib/functools.py 33 34 def wraps(wrapped, 35 assigned = WRAPPER_ASSIGNMENTS, 36 updated = WRAPPER_UPDATES): 37 """Decorator factory to apply update_wrapper() to a wrapper function 38 39 Returns a decorator that invokes update_wrapper() with the decorated 40 function as the wrapper argument and the arguments to wraps() as the 41 remaining arguments. Default arguments are as for update_wrapper(). 42 This is a convenience function to simplify applying partial() to 43 update_wrapper(). 44 """ 45 return partial(update_wrapper, wrapped=wrapped, 46 assigned=assigned, updated=updated) 47 48 49 ============================================================================= 50 需要慢慢去学习
1 django/views/generic/base.py
2
3 class View(object):
4 """
5 Intentionally simple parent class for all views. Only implements
6 dispatch-by-method and simple sanity checking.
7 """
8
9 http_method_names = ['get', 'post', 'put', 'patch', 'delete', 'head', 'options', 'trace']
10
11 def __init__(self, **kwargs):
12 """
13 Constructor. Called in the URLconf; can contain helpful extra
14 keyword arguments, and other things.
15 """
16 # Go through keyword arguments, and either save their values to our
17 # instance, or raise an error.
18 for key, value in six.iteritems(kwargs):
19 setattr(self, key, value)
20
21 @classonlymethod
22 def as_view(cls, **initkwargs):
23 """
24 Main entry point for a request-response process.
25 """
26 for key in initkwargs:
27 if key in cls.http_method_names:
28 raise TypeError("You tried to pass in the %s method name as a "
29 "keyword argument to %s(). Don't do that."
30 % (key, cls.__name__))
31 if not hasattr(cls, key):
32 raise TypeError("%s() received an invalid keyword %r. as_view "
33 "only accepts arguments that are already "
34 "attributes of the class." % (cls.__name__, key))
35
36 def view(request, *args, **kwargs):
37 self = cls(**initkwargs)
38 if hasattr(self, 'get') and not hasattr(self, 'head'):
39 self.head = self.get
40 self.request = request
41 self.args = args
42 self.kwargs = kwargs
43 return self.dispatch(request, *args, **kwargs)
44 view.view_class = cls
45 view.view_initkwargs = initkwargs
46
47 # take name and docstring from class
48 update_wrapper(view, cls, updated=())
49
50 # and possible attributes set by decorators
51 # like csrf_exempt from dispatch
52 update_wrapper(view, cls.dispatch, assigned=())
53 return view
54
55 def dispatch(self, request, *args, **kwargs):
56 # Try to dispatch to the right method; if a method doesn't exist,
57 # defer to the error handler. Also defer to the error handler if the
58 # request method isn't on the approved list.
59 if request.method.lower() in self.http_method_names:
60 handler = getattr(self, request.method.lower(), self.http_method_not_allowed)
61 else:
62 handler = self.http_method_not_allowed
63 return handler(request, *args, **kwargs)
64
65 def http_method_not_allowed(self, request, *args, **kwargs):
66 logger.warning('Method Not Allowed (%s): %s', request.method, request.path,
67 extra={
68 'status_code': 405,
69 'request': request
70 }
71 )
72 return http.HttpResponseNotAllowed(self._allowed_methods())
73
74 def options(self, request, *args, **kwargs):
75 """
76 Handles responding to requests for the OPTIONS HTTP verb.
77 """
78 response = http.HttpResponse()
79 response['Allow'] = ', '.join(self._allowed_methods())
80 response['Content-Length'] = '0'
81 return response
82
83 def _allowed_methods(self):
84 return [m.upper() for m in self.http_method_names if hasattr(self, m)]
85
86
========================================================================= （2）在urls.py里面出现的pk是怎么回事 我去rest_framework/generics.py里面看了class GenericAPIView(views.APIView)的代码 下面是我截选的代码： 1 class GenericAPIView(views.APIView): 2 queryset = None 3 serializer_class = None 4 5 # If you want to use object lookups other than pk, set 'lookup_field'. 6 # For more complex lookup requirements override `get_object()`. 7 lookup_field = 'pk' 8 lookup_url_kwarg = None 9 def get_object(self): 10 "" " 11 Returns the object the view is displaying. 12 13 You may want to override this if you need to provide non-standard 14 queryset lookups. Eg if objects are referenced using multiple 15 keyword arguments in the url conf. 16 "" " 17 queryset = self.filter_queryset(self.get_queryset()) 18 19 # Perform the lookup filtering. 20 lookup_url_kwarg = self.lookup_url_kwarg or self.lookup_field 21 22 assert lookup_url_kwarg in self.kwargs, ( 23 'Expected view %s to be called with a URL keyword argument ' 24 'named "%s". Fix your URL conf, or set the `.lookup_field` ' 25 'attribute on the view correctly.' % 26 (self.__class__.__name__, lookup_url_kwarg) 27 ) 28 29 filter_kwargs = {self.lookup_field: self.kwargs[lookup_url_kwarg]} 30 obj = get_object_or_404(queryset, **filter_kwargs) 31 32 # May raise a permission denied 33 self.check_object_permissions(self.request, obj) 34 35 return obj 36 ~ pk是框架默认的值，如果不想用"pk"就要修改lookup_field这个变量 （3）RetrieveAPIView 表示什么 202 class RetrieveAPIView (mixins.RetrieveModelMixin, 203 GenericAPIView): 204 """ 205 Concrete view for retrieving a model instance. 206 """ 207 def get(self, request, *args, **kwargs): 208 return self.retrieve(request, *args, **kwargs) 209