How to bypass "type X is not JSON serializable" error in python

When working with dictionaries in python, sometimes the attributes types are not serializable. This ca happen specially with dates and times, which are common attributes when building API interfaces for example.

The problem comes when we need to convert it as a JSON string. Take the following snippet:

import json
from datetime import date

today = date.today()
dict = { 
  'today': today,
  'foo': 'bar'
}
print(json.dumps(dict))

This code will fail with the following error: TypeError: Object of type date is not JSON serializable

To avoid this, we can pass the “default” argument to the dumps method:

print(json.dumps(dict, default=str))

This way, in case some type cannot be serialized, it will be converted to string.