backup

backend/app/utils/display_sanitizer.py

@@ -0,0 +1,28 @@
+"""Display sanitization utilities for HTML render contexts.
+
+All user-supplied values echoed in error messages or other HTML-rendered
+output MUST be sanitized first. This module provides the canonical
+sanitize_for_display() function.
+"""
+
+from __future__ import annotations
+
+import html
+
+
+def sanitize_for_display(value: str) -> str:
+    """Escape HTML special characters in user-supplied strings.
+
+    Use this before interpolating user input into any string that will be
+    rendered in an HTML context (e.g. error messages, admin UI, email).
+
+    Does NOT over-escape: JSON responses are not HTML contexts and do not
+    need this treatment. Apply sanitization only at HTML render boundaries.
+
+    Args:
+        value: Raw user-supplied string.
+
+    Returns:
+        The string with HTML special characters escaped.
+    """
+    return html.escape(value, quote=True)