Question

尝试使用json.dumps（）将字节类型为键的字典对象转换为json。事先不知道字典对象的格式。使用json.dumps（Convert bytes embedded in list (or dict) to str for use with json.dumps）时，找到了具有字节值的数组或字典的解决方案，但未找到用于字节键的解决方案。

import json

class BytesDump(json.JSONEncoder):
    def default(self, obj):
        if isinstance(obj, bytes):
            return obj.decode()
        return json.JSONEncoder.default(self, obj)

foo = {'name': b'bob', 'age': 33, 'attributes': {'hair': b'brown', 'arms': 2}}
bar = {b'name': b'bob', b'age': 33, b'attributes': {b'hair': b'brown', b'arms': 2}}

print(json.dumps(foo, cls=BytesDump)) # this works
print(json.dumps(bar, cls=BytesDump)) # this doesn't work

上面的输出

{"name": "bob", "age": 33, "attributes": {"hair": "brown", "arms": 2}}
Traceback (most recent call last):
  File "./test.py", line 15, in <module>
    print(json.dumps(bar, cls=BytesDump))
  File "/usr/local/lib/python3.6/json/__init__.py", line 238, in dumps
    **kw).encode(obj)
  File "/usr/local/lib/python3.6/json/encoder.py", line 199, in encode
    chunks = self.iterencode(o, _one_shot=True)
  File "/usr/local/lib/python3.6/json/encoder.py", line 257, in iterencode
    return _iterencode(o, 0)
TypeError: keys must be a string

Answer 1

您可以对字典进行预处理，以将键（如果为字节）以递归方式转换为字符串

import json
# your dump code for values, unmodified
class BytesDump(json.JSONEncoder):
    def default(self, obj):
        if isinstance(obj, bytes):
            return obj.decode()
        return json.JSONEncoder.default(self, obj)

# recursive key as string conversion for byte keys
def keys_string(d):
    rval = {}
    for k,v in d.items():
        if isinstance(k,bytes):
            k = k.decode()
        if isinstance(v,dict):
            v = keys_string(v)
        elif isinstance(v,(tuple,list,set)):
            v = [keys_string(x) for x in v]

        rval[k] = v
    return rval

print(json.dumps(keys_string(bar), cls=BytesDump))

具有：

bar = {b'name': b'bob', b'age': 33, b'attributes': {b'hair': b'brown', b'arms': 2},
b'other': [{b'hair': b'brown', b'arms': 2}]}

打印：

{"attributes": {"hair": "brown", "arms": 2}, "age": 33, "name": "bob", "other": [{"hair": "brown", "arms": 2}]}

Answer 2

看起来您需要使用递归实用程序功能：

import json

def decode_dict(d):
    result = {}
    for key, value in d.items():
        if isinstance(key, bytes):
            key = key.decode()
        if isinstance(value, bytes):
            value = value.decode()
        elif isinstance(value, dict):
            value = decode_dict(value)
        result.update({key: value})
    return result


bar = {b'name': b'bob', b'age': 33, b'attributes': {b'hair': b'brown', b'arms': 2}}
print(json.dumps(decode_dict(bar)))

输出：

{"name": "bob", "age": 33, "attributes": {"hair": "brown", "arms": 2}}

字典上的json.dumps带有密钥字节

2 个答案: