Modern Python Standard Library Cookbook

How it works...

To generate JSON representation of Python objects, the json.dumps method is used. This method accepts an additional argument, cls, where a custom encoder class can be provided:

json.dumps({'key': 'value', cls=CustomJSONEncoder)

The default method of the provided class will be called whenever it is required to encode an object that the encoder doesn't know how to encode.

Our CustomJSONEncoder class provides a default method that handles encoding dates, times, generators, decimals, and any custom class that provides a __json__ method:

class CustomJSONEncoder(json.JSONEncoder): def default(self, obj): if hasattr(obj, '__json__') and callable(obj.__json__): return obj.__json__() elif isinstance(obj, (datetime.datetime, datetime.time)): ...