Python JSON Encoder able to encode arbitrary precision decimals as numbers

gistfile1.txt

import json, re, uuid

class JsonDecimalAwareEncoder(json.JSONEncoder):
    def __init__(self, *args, **kw):
        self.original_numbers = {}
        super().__init__(*args, **kw)
        
    def default(self, obj):
        if isinstance(obj, decimal.Decimal):
            key = uuid.uuid4()
            self.original_numbers[key] = obj
            return f"__CUSTOM_ENC_{key}__"
        return super().default(obj)
    
    def replace(self, match):
        key = uuid.UUID(match.groups()[0])
        return str(self.original_numbers[key])

    def encode(self, obj):
        intermediary = super().encode(obj)
        expr = re.compile(f"\\\"__CUSTOM_ENC_({'|'.join(str(key) for key in self.original_numbers)})__\\\"")
        result = expr.sub(self.replace, intermediary)
        return result

Python can already decode arbitrary decimal numbers, all that is needed is to pass a parse_float argument to standard json.loads call like in: json.loads(data, parse_float=decimal.Decimal) . To encode using this recibe, just do: data= JsonDecimalAwareEncoder().encode(obj)