自定义 JSON 编码器引发“对象不可 JSON 可序列化”错误

Question

我正在尝试为我的一个类创建一个自定义 JSON 编码器。我创建了一个简化版本来尝试该方法并且它有效，但是当我在项目中应用该方法时，它不断抛出错误：

    json.dump(obj=self.tree, fp=f, cls=BookmarkEncoder, ensure_ascii=False)

  File "/usr/lib/python3.8/json/__init__.py", line 179, in dump

    for chunk in iterable:

  File "/usr/lib/python3.8/json/encoder.py", line 438, in _iterencode

    o = _default(o)

  File "/usr/lib/python3.8/json/encoder.py", line 179, in default

    raise TypeError(f'Object of type {o.__class__.__name__} '

TypeError: Object of type HTMLBookmark is not JSON serializable

我试图转换的对象是BeautifulSoupTag类的修改版本，该类的代码如下：

class HTMLBookmark(Tag, Node):

    """TreeBuilder class, used to add additional functionality to the

    BeautifulSoup Tag class. The following functionality is added:

    - add id to each folder("h3")/url("a") being imported

    - add property access to the Tag class' attributes

      (date_added, icon, icon_uri, id, index, title, type and url)

      which are usually found in the 'self.attrs' dictionary.

    - add a setter for (id, index and title)

    - redirect the self.children from an iterator iter(self.contents)

    to a list (self.contents) directly"""

    counter = itertools.count(start=2)

    def __init__(self, *args, **kwargs):

        super().__init__(*args, **kwargs)

        if self.name in ("a", "h3"):

            if not self.attrs.get("id"):

                self.attrs["id"] = next(__class__.counter)

    @property

    def date_added(self):

        date_added = self.attrs.get("add_date")

        if not date_added:

            date_added = round(time.time() * 1000)

        return int(date_added)

    @property

    def icon(self):

        return self.attrs.get("icon")

    @property

    def icon_uri(self):

        return self.attrs.get("iconuri")

    @property

    def id(self):

        return self.attrs.get("id")

    @id.setter

    def id(self, new_id):

        self.attrs["id"] = new_id

    @property

    def index(self):

        return self.attrs.get("index")

    @index.setter

    def index(self, new_index):

        self.attrs["index"] = new_index

Answer 1

看起来你有一个错字：def defaut(self, o):应该是def default(self, o):