""" Functions for working with "safe strings": strings that can be displayed safely without further escaping in HTML. Marking something as a "safe string" means that the producer of the string has already turned characters that should not be interpreted by the HTML engine (e.g. '<') into the appropriate entities. """ from functools import wraps from django.utils.functional import keep_lazy class SafeData: __slots__ = () def __html__(self): """ Return the html representation of a string for interoperability. This allows other template engines to understand Django's SafeData. """ return self class SafeString(str, SafeData): """ A str subclass that has been specifically marked as "safe" for HTML output purposes. """ __slots__ = () def __add__(self, rhs): """ Concatenating a safe string with another safe bytestring or safe string is safe. Otherwise, the result is no longer safe. """ t = super().__add__(rhs) if isinstance(rhs, SafeData): return SafeString(t) return t def __str__(self): return self SafeText = SafeString # For backwards compatibility since Django 2.0. def _safety_decorator(safety_marker, func): @wraps(func) def wrapper(*args, **kwargs): return safety_marker(func(*args, **kwargs)) return wrapper @keep_lazy(SafeString) def mark_safe(s): """ Explicitly mark a string as safe for (HTML) output purposes. The returned object can be used everywhere a string is appropriate. If used on a method as a decorator, mark the returned data as safe. Can be called multiple times on a single string. """ if hasattr(s, "__html__"): return s if callable(s): return _safety_decorator(mark_safe, s) return SafeString(s)