Class Hashids

hashids.py:165–273

Hashes and restores values using the "hashids" algorithm.

class Hashids(object):
    """Hashes and restores values using the "hashids" algorithm."""
    ALPHABET = 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890'

    def __init__(self, salt='', min_length=0, alphabet=ALPHABET):
        """
        Initializes a Hashids object with salt, minimum length, and alphabet.

        :param salt: A string influencing the generated hash ids.
        :param min_length: The minimum length for generated hashes
        :param alphabet: The characters to use for the generated hash ids.
        """
        self._min_length = max(int(min_length), 0)
        self._salt = salt

        separators = ''.join(x for x in 'cfhistuCFHISTU' if x in alphabet)
        alphabet = ''.join(x for i, x in enumerate(alphabet)
                           if alphabet.index(x) == i and x not in separators)

        len_alphabet, len_separators = len(alphabet), len(separators)
        if len_alphabet + len_separators < 16:
            raise ValueError('Alphabet must contain at least 16 '
                             'unique characters.')

        separators = _reorder(separators, salt)

        min_separators = _index_from_ratio(len_alphabet, RATIO_SEPARATORS)

        number_of_missing_separators = min_separators - len_separators
        if number_of_missing_separators > 0:
            separators += alphabet[:number_of_missing_separators]
            alphabet = alphabet[number_of_missing_separators:]
            len_alphabet = len(alphabet)

        alphabet = _reorder(alphabet, salt)
        num_guards = _index_from_ratio(len_alphabet, RATIO_GUARDS)
        if len_alphabet < 3:
            guards = separators[:num_guards]
            separators = separators[num_guards:]
        else:
            guards = alphabet[:num_guards]
            alphabet = alphabet[num_guards:]

        self._alphabet = alphabet
        self._guards = guards
        self._separators = separators

        # Support old API
        self.decrypt = _deprecated(self.decode, "decrypt")
        self.encrypt = _deprecated(self.encode, "encrypt")

    def encode(self, *values):
        """Builds a hash from the passed `values`.

        :param values The values to transform into a hashid

        >>> hashids = Hashids('arbitrary salt', 16, 'abcdefghijkl0123456')
        >>> hashids.encode(1, 23, 456)