import re
# ============================================================================
# Input sanitization
# ============================================================================
def sanitize_user_id(user_id: str) -> str:
"""Allow only alphanumeric, underscore, hyphen"""
sanitized = re.sub(r"[^a-zA-Z0-9_-]", "", user_id).strip()
if not sanitized:
raise ValueError("User ID cannot be empty after sanitisation")
if len(sanitized) > 100:
sanitized = sanitized[:100]
return sanitized
def sanitize_user_message(message: str, max_length: int = 5000) -> str:
"""Remove control characters and enforce length limits"""
# Remove null bytes and control characters
sanitized = "".join(char for char in message if ord(char) >= 32 or char in "\n\t")
sanitized = sanitized.strip()
if not sanitized:
raise ValueError("Message cannot be empty")
if len(sanitized) > max_length:
sanitized = sanitized[:max_length]
return sanitized
def sanitize_tool_input(tool_input: dict) -> dict:
"""Basic sanitisation: trim strings, enforce length limits"""
# NOTE should validate schema, but overkill for an example app
sanitized = {}
for param, value in tool_input.items():
if isinstance(value, str):
# Remove control chars, trim, limit length
value = "".join(c for c in value if ord(c) >= 32 or c in "\n\t")
value = value.strip()[:5000]
if not value:
raise ValueError(f"Parameter '{param}' cannot be empty")
sanitized[param] = value
elif isinstance(value, list):
# sanitize list items (strings only)
sanitized[param] = [_sanitize_string(item) for item in value]
else:
# Pass through numbers, bools, etc.
sanitized[param] = value
return sanitized
def _sanitize_string(value: str, max_length: int = 5000) -> str:
"""Helper: sanitize a single string"""
value = "".join(c for c in value if ord(c) >= 32 or c in "\n\t")
value = value.strip()[:max_length]
if not value:
raise ValueError("String value cannot be empty")
return value
