html.py 文件源码

def html_safe(klass):
    """
    A decorator that defines the __html__ method. This helps non-Django
    templates to detect classes whose __str__ methods return SafeText.
    """
    if '__html__' in klass.__dict__:
        raise ValueError(
            "can't apply @html_safe to %s because it defines "
            "__html__()." % klass.__name__
        )
    if six.PY2:
        if '__unicode__' not in klass.__dict__:
            raise ValueError(
                "can't apply @html_safe to %s because it doesn't "
                "define __unicode__()." % klass.__name__
            )
        klass_unicode = klass.__unicode__
        klass.__unicode__ = lambda self: mark_safe(klass_unicode(self))
        klass.__html__ = lambda self: unicode(self)  # NOQA: unicode undefined on PY3
    else:
        if '__str__' not in klass.__dict__:
            raise ValueError(
                "can't apply @html_safe to %s because it doesn't "
                "define __str__()." % klass.__name__
            )
        klass_str = klass.__str__
        klass.__str__ = lambda self: mark_safe(klass_str(self))
        klass.__html__ = lambda self: str(self)
    return klass