1
class JsonResponse(HttpResponse):
2

3
    def __init__(self, data, encoder=DjangoJSONEncoder, safe=True,
4
                 json_dumps_params=None, **kwargs):
5
        if safe and not isinstance(data, dict):
6
            raise TypeError(
7
                'In order to allow non-dict objects to be serialized set the '
8
                'safe parameter to False.'
9
            )
10
        if json_dumps_params is None:
11
            json_dumps_params = {}
12
        kwargs.setdefault('content_type', 'application/json')
13
        # 数据序列化发生在这里
14
        data = json.dumps(data, cls=encoder, **json_dumps_params)
15
        super(JsonResponse, self).__init__(content=data, **kwargs)

1
def file_upload(request):
2
    if request.method == 'POST':
3
        # 获取文件数据
4
        print(request.FILES)
5
        # <MultiValueDict: {'file': [<InMemoryUploadedFile: img.png (image/png)>]}>
6

7
        # 提取文件数据 - 文件对象
8
        file_obj = request.FILES.get('file')
9
        # 提取文件名字 file_obj.name
10
        with open(file_obj.name, 'wb') as f:
11
            # 逐行读取文件数据
12
            # 官方推荐 加上 chunks 方法 等价于 一行行获取
13
            for line in file_obj.chunks():
14
                f.write(line)
15
    return render(request, 'file.html')

1
@classonlymethod
2
    def as_view(cls, **initkwargs):
3
        """
4
        Main entry point for a request-response process.
5
        """
6
        for key in initkwargs:
7
            if key in cls.http_method_names:
8
                raise TypeError("You tried to pass in the %s method name as a "
9
                                "keyword argument to %s(). Don't do that."
10
                                % (key, cls.__name__))
11
            if not hasattr(cls, key):
12
                raise TypeError("%s() received an invalid keyword %r. as_view "
13
                                "only accepts arguments that are already "
14
                                "attributes of the class." % (cls.__name__, key))
15

16
        def view(request, *args, **kwargs):
17
            self = cls(**initkwargs)
18
            if hasattr(self, 'get') and not hasattr(self, 'head'):
19
                self.head = self.get
20
            self.request = request
21
            self.args = args
22
            self.kwargs = kwargs
23
            return self.dispatch(request, *args, **kwargs)
24
        view.view_class = cls
25
        view.view_initkwargs = initkwargs
26

27
        # take name and docstring from class
28
        update_wrapper(view, cls, updated=())
29

30
        # and possible attributes set by decorators
31
        # like csrf_exempt from dispatch
32
        update_wrapper(view, cls.dispatch, assigned=())
33
        return view

1
def view(request, *args, **kwargs):
2
        # 参数 cls 就是我们自己写的类
3
        self = cls(**initkwargs)
4
        # 等价于 self = MyLogin(**initkwargs) ---- 产生一个我们自己写的类的对象
5
        if hasattr(self, 'get') and not hasattr(self, 'head'):
6
            self.head = self.get
7
        # 给我们的对象赋值属性
8
        self.request = request
9
        self.args = args
10
        self.kwargs = kwargs
11
        '''
12
        在看python源码的时候，一定要时刻注意面向对象属性方法查找顺序
13
            先从对象自己找
14
            再去产生对象的类里面找
15
            之后再去父类找
16
        总结：在看源码时，如果遇到 self.x 操作时，一定要时刻注意当前这个self到底是谁
17
         '''
18
        return self.dispatch(request, *args, **kwargs)

1
http_method_names = ['get', 'post', 'put', 'patch', 'delete', 'head', 'options', 'trace']
2

3
    # CBV 的 精髓 !!!
4
    def dispatch(self, request, *args, **kwargs):
5
        # Try to dispatch to the right method; if a method doesn't exist,
6
        # defer to the error handler. Also defer to the error handler if the
7
        # request method isn't on the approved list.
8
        # 获取当前请求的小写格式 然后比对当前请求方式是否合法
9
        # 以 get 请求为例
10
        if request.method.lower() in self.http_method_names:
11
            '''
12
            反射：通过字符串来操作对象的属性或方法
13
            '''
14
            # self 是我们自己写的类产生的对象
15
            # handler = getattr(自己写的类产生的对象,'get',当找不到get属性或方法时就会用到第三个参数)
16
            # 因为我们在自己的类里面重写了 get 方法 ，所以这里的 handler 就变成了我们自己写的 get方法
17
            # handler = 我们自己写的类里面的get方法
18
            handler = getattr(self, request.method.lower(), self.http_method_not_allowed)
19
        else:
20
            handler = self.http_method_not_allowed
21

22
        # 自动调用 get 方法
23
        return handler(request, *args, **kwargs)