Read config from a json file

[selfboot]

Read the config from json:

with open(config_path, 'rb') as f:
    try:
        config = json.loads(f.read().decode('utf8'), object_hook=_decode_dict)
    except ValueError as e:
        logging.error('found an error in config.json: %s', e.message)
        sys.exit(1)

As follows:

• open() returns a file object, and is most commonly used with two arguments: open(filename, mode).
• To read a file’s contents, call f.read(size), which reads some quantity of data and returns it as a string. size is an optional numeric argument.
• To convert a string of bytes(<type 'str'> in py2 ) to a unicode string is known as decoding. More: Unicode HOWTO
• json.loads deserialize s (a str or unicode instance containing a JSON document) to a Python object using this conversion table. If s is a str instance and is encoded with an ASCII based encoding other than UTF-8 (e.g. latin-1), then an appropriate encoding name must be specified. Encodings that are not ASCII based (such as UCS-2) are not allowed and should be decoded to unicode first.
• object_hook is an optional function that will be called with the result of any object literal decoded (a dict). The return value of object_hook will be used instead of the dict. This feature can be used to implement custom decoders.

This conversion table

JSON	Python
object	dict
array	list
string	unicode
number (int)	int, long
number (real)	float
true	True
false	False
null	None

[selfboot]

Demo Json File:

{
    "server": "127.0.0.1",
    "key": ["1", "中", "文"],
    "port": "测试"
}

Load json with following code:

with open(config_path, 'rb') as f:
    try:
        """
        # 1
        {u'port': '\xe6\xb5\x8b\xe8\xaf\x95', u'key': ['1', '\xe4\xb8\xad', '\xe6\x96\x87'], u'server': '127.0.0.1'}
        ['1', '\xe4\xb8\xad', '\xe6\x96\x87']
        文
        """
        config = json.loads(f.read().decode('utf8'), object_hook=_decode_dict)
        """
        # 2
        {u'port': u'\u6d4b\u8bd5', u'key': [u'1', u'\u4e2d', u'\u6587'], u'server': u'127.0.0.1'}
        [u'1', u'\u4e2d', u'\u6587']
        文
        """
        # config = json.loads(f.read().decode('utf8'))
    except ValueError as e:
        sys.exit(1)

    print(config)
    print(config["key"])
    print(config["key"][2])