From 6d9001c8c701da6f5cfb83eaabaf10e7e95a3156 Mon Sep 17 00:00:00 2001
From: Jeff McAdams <jeffmca@gmail.com>
Date: Fri, 18 Oct 2024 16:58:18 -0400
Subject: [PATCH] Add EUIType

EUIType can store netaddr EUI objects (either EUI48 or EUI64), converting to string when adding to the database and converting back to an EUI object when reading back out of the database.

This is to go along with IPAddressType to support storing and validating network MAC addresses (which are just EUI48s).

Code cribbed pretty heavily from IPAddressType and (less) ColorType.
---
 sqlalchemy_utils/__init__.py       |  1 +
 sqlalchemy_utils/types/__init__.py |  1 +
 sqlalchemy_utils/types/eui.py      | 76 ++++++++++++++++++++++++++++++
 3 files changed, 78 insertions(+)
 create mode 100644 sqlalchemy_utils/types/eui.py

diff --git a/sqlalchemy_utils/__init__.py b/sqlalchemy_utils/__init__.py
index 84633f6b..eff5bcfb 100644
--- a/sqlalchemy_utils/__init__.py
+++ b/sqlalchemy_utils/__init__.py
@@ -70,6 +70,7 @@
     EncryptedType,
     EnrichedDateTimeType,
     EnrichedDateType,
+    EUIType,
     instrumented_list,
     InstrumentedList,
     Int8RangeType,
diff --git a/sqlalchemy_utils/types/__init__.py b/sqlalchemy_utils/types/__init__.py
index 33242a6f..cc490a54 100644
--- a/sqlalchemy_utils/types/__init__.py
+++ b/sqlalchemy_utils/types/__init__.py
@@ -14,6 +14,7 @@
 )
 from .enriched_datetime.enriched_date_type import EnrichedDateType  # noqa
 from .ip_address import IPAddressType  # noqa
+from .eui import EUIType
 from .json import JSONType  # noqa
 from .locale import LocaleType  # noqa
 from .ltree import LtreeType  # noqa
diff --git a/sqlalchemy_utils/types/eui.py b/sqlalchemy_utils/types/eui.py
new file mode 100644
index 00000000..b28fa2a3
--- /dev/null
+++ b/sqlalchemy_utils/types/eui.py
@@ -0,0 +1,76 @@
+from typing import Any, Type
+
+from sqlalchemy import types
+from ..exceptions import ImproperlyConfigured
+from .scalar_coercible import ScalarCoercible
+
+eui = None
+try:
+    from netaddr import EUI
+    python_eui_type = EUI
+except (ImportError, AttributeError):
+    python_eui_type = None
+
+
+class EUIType(ScalarCoercible, types.TypeDecorator):
+    """
+
+    EUIType provides a way for saving EUI (from netaddr package) objects
+    into database.  EUIType saves EUI objects as strings on the way in
+    and converts them back to objects when querying the database.
+
+    EUI objects can store either EUI64 identifiers or EUI48 identifiers
+    EUI48 is frequently used for network MAC addresses.
+
+    ::
+
+        from netaddr import EUI
+        from sqlalchemy_utils import EUI
+
+
+        class Interface(Base):
+            __tablename__ = 'interface'
+            id = sa.Column(sa.Integer, autoincrement=True)
+            name = sa.Column(sa.Unicode(50))
+            mac_address = sa.Column(EUIType)
+
+        intf = Interface()
+        intf.mac_address = EUI('a1:b2:c3:d4:e5:f6')
+        session.commit()
+
+
+    Querying the database returns EUI objects:
+
+    ::
+
+        import netaddr
+
+        intf = session.query(Interface).first()
+
+        intf.mac_address.dialect = netaddr.mac_unix
+        intf.mac_address
+        # 'a1:b2:c3:d4:e5:f6'
+
+    .. _netaddr: https://github.com/netaddr/netaddr
+    """
+
+    impl = types.Unicode(50)
+    cache_ok = True
+
+    def __init__(self, max_length=50, *args, **kwargs):
+        super().__init__(*args, **kwargs)
+        self.impl = types.Unicode(max_length)
+
+
+    def process_bind_param(selfself, value, dialect):
+        return str(value) if value else None
+
+    def process_result_value(selfself, value, dialect):
+        return EUI(value) if value else None
+
+    def _coerce(self, value):
+        return EUI(value) if value else None
+
+    @property
+    def python_type(self):
+        return self.impl.type.python_type