Class Rule

src/licensedcode/models.py:2263–2571

A detection rule object with support for data and text files.

@attr.s(slots=True)
class Rule(BasicRule):
    """
    A detection rule object with support for data and text files.
    """

    def __attrs_post_init__(self, *args, **kwargs):
        self.setup()

    @classmethod
    def from_file(cls, rule_file, is_builtin=True):
        """
        Return a new Rule object loaded from a file stored at
        ``rule_file`` with the text and it's data as with YAML frontmatter.
        """
        rule = Rule(is_builtin=is_builtin)
        rule.load_data(rule_file=rule_file)
        return rule

    @property
    def pysafe_expression(self):
        """
        Return a python safe identifier, for use in rule identifiers"""
        return python_safe_name(self.license_expression)

    def load_data(self, rule_file):
        """
        Load data from ``rule_file`` which has both the text and the data (as YAML forntmatter).
        Check presence of text file to determine if this is a special synthetic rule.
        """
        if self.is_synthetic:
            if not self.text:
                raise InvalidRule(
                    f'Invalid synthetic rule without text: {self}: {self.text!r}')
            return self

        if not rule_file:
            raise InvalidRule(
                f'Cannot load rule without its corresponding rule_file: '
                f'{self}: file://{rule_file}')

        self.identifier = file_name(rule_file)

        try:
            self.load(rule_file=rule_file)
        except Exception:
            trace = traceback.format_exc()
            raise InvalidRule(f'While loading: file://{rule_file}\n{trace}')

        return self

    def tokens(self):
        """
        Return a sequence of token strings for this rule text.

        SIDE EFFECT: Computed attributes such as "length", "relevance",
        "is_continuous",  "minimum_coverage" and "stopword_by_pos" are
        recomputed as a side effect.
        """