Decode a nested JSON file containing escaped JSON values

decode_nested_json.py

#!/usr/bin/env python3
#
# Decode a nested JSON object containing escaped JSON strings as values
# Pass the JSON file as a command line argument, or use "-" to read from stdin.

import json


def decode_json_object(json_object):
    """Decode a JSON object containing escaped JSON strings as values"""
    for key, value in json_object.items():
        if isinstance(value, str):
            try:
                json_object[key] = json.loads(value)
            except ValueError:
                pass
    return json_object


def decode_json(json_string):
    """Decode a nested JSON object containing escaped JSON strings as values"""
    return json.loads(json_string, object_hook=decode_json_object)


if __name__ == "__main__":
    import sys

    if len(sys.argv) != 2:
        print(f"Usage: {sys.argv[0]} <json_file>", file=sys.stderr)
        sys.exit(1)

    if sys.argv[1] == "-":
        json_string = sys.stdin.read()
    else:
        with open(sys.argv[1]) as f:
            json_string = f.read()
    print(json.dumps(decode_json(json_string), indent=4))