Create validator_cidr.py

src/django-lan/utils/validators/validator_cidr.py

@@ -0,0 +1,93 @@
+# -*- coding: utf-8 -*-
+
+
+# =============================================================================
+# Docstring
+# =============================================================================
+
+"""
+Provides CIDR Validation Function
+=================================
+
+Validates CIDR (Classless Inter-Domain Routing) notations which are used to
+describe the network portion and the host identifier portion of an IP address.
+
+Links:
+- https://en.wikipedia.org/wiki/Classless_Inter-Domain_Routing
+
+"""
+
+
+# =============================================================================
+# Import
+# =============================================================================
+
+# Import | Standard Library
+from typing import Any
+import ipaddress
+
+# Import | Libraries
+from django.core.exceptions import ValidationError
+from django.utils.translation import gettext_lazy as _
+
+# Import | Local Modules
+
+
+# =============================================================================
+# Variables
+# =============================================================================
+
+
+# =============================================================================
+# Functions
+# =============================================================================
+
+def validate_cidr(value: Any) -> None:
+    """
+    CIDR Validation Function
+    ========================
+
+    Validates that the provided value is a valid CIDR notation.
+
+    CIDR notation is a compact representation of an IP address and its
+    associated network mask. CIDR notation is a more flexible and universal
+    method to allocate IP addresses than the older system based on classes
+    (A, B, C).
+
+    Args:
+        value (Any): The CIDR notation to validate. It's expected to be a
+            string, but the function handles other types by attempting
+            conversion.
+
+    Raises:
+        ValidationError: If the provided value is not a valid CIDR notation.
+
+    Examples:
+        >>> validate_cidr("192.168.1.0/24")
+        None
+        >>> validate_cidr("192.168.1.0/35")  # This example should raise a
+        ValidationError
+        ValidationError: Invalid CIDR notation
+
+    """
+
+    try:
+        # Allows network address to be non-strict
+        ipaddress.ip_network(
+            value,
+            strict = False,
+        )
+    except ValueError:
+        raise ValidationError(
+            _("Invalid CIDR notation"),
+            code = "invalid_cidr",
+        )
+
+
+# =============================================================================
+# Public Interface
+# =============================================================================
+
+__all__ = [
+    "validate_cidr",
+]