From 07fa844c43e2540f61973ddce8d900834725d99d Mon Sep 17 00:00:00 2001
From: Paulus Schoutsen <balloob@gmail.com>
Date: Mon, 24 Feb 2020 08:35:02 -0800
Subject: [PATCH] Speed up validate_entity_id (#32137)

* Speed up validate_entity_id

* Add some more invalid entity IDs

* Adjust regular expression

* Extend and sort test cases

* Update regular expression, more cases, faster

* Adjust tests, allow start with number, disallow double underscore

Co-authored-by: Franck Nijhof <frenck@frenck.nl>
---
 homeassistant/core.py                       |  8 ++++--
 homeassistant/scripts/benchmark/__init__.py |  9 ++++++
 tests/test_core.py                          | 31 +++++++++++++++++++++
 3 files changed, 46 insertions(+), 2 deletions(-)

diff --git a/homeassistant/core.py b/homeassistant/core.py
index c17c1f698ce..a1d9a83d1ad 100644
--- a/homeassistant/core.py
+++ b/homeassistant/core.py
@@ -12,6 +12,7 @@ import functools
 import logging
 import os
 import pathlib
+import re
 import threading
 from time import monotonic
 from types import MappingProxyType
@@ -63,7 +64,7 @@ from homeassistant.exceptions import (
     ServiceNotFound,
     Unauthorized,
 )
-from homeassistant.util import location, slugify
+from homeassistant.util import location
 from homeassistant.util.async_ import fire_coroutine_threadsafe, run_callback_threadsafe
 import homeassistant.util.dt as dt_util
 from homeassistant.util.unit_system import IMPERIAL_SYSTEM, METRIC_SYSTEM, UnitSystem
@@ -103,12 +104,15 @@ def split_entity_id(entity_id: str) -> List[str]:
     return entity_id.split(".", 1)
 
 
+VALID_ENTITY_ID = re.compile(r"^(?!.+__)(?!_)[\da-z_]+(?<!_)\.(?!_)[\da-z_]+(?<!_)$")
+
+
 def valid_entity_id(entity_id: str) -> bool:
     """Test if an entity ID is a valid format.
 
     Format: <domain>.<entity> where both are slugs.
     """
-    return "." in entity_id and slugify(entity_id) == entity_id.replace(".", "_", 1)
+    return VALID_ENTITY_ID.match(entity_id) is not None
 
 
 def valid_state(state: str) -> bool:
diff --git a/homeassistant/scripts/benchmark/__init__.py b/homeassistant/scripts/benchmark/__init__.py
index 58125bc4829..4d7df6d7248 100644
--- a/homeassistant/scripts/benchmark/__init__.py
+++ b/homeassistant/scripts/benchmark/__init__.py
@@ -185,3 +185,12 @@ def _logbook_filtering(hass, last_changed, last_updated):
     list(logbook.humanify(None, yield_events(event)))
 
     return timer() - start
+
+
+@benchmark
+async def valid_entity_id(hass):
+    """Run valid entity ID a million times."""
+    start = timer()
+    for _ in range(10 ** 6):
+        core.valid_entity_id("light.kitchen")
+    return timer() - start
diff --git a/tests/test_core.py b/tests/test_core.py
index 0c7acfbba0e..f5a6f4718cd 100644
--- a/tests/test_core.py
+++ b/tests/test_core.py
@@ -1206,3 +1206,34 @@ async def test_async_functions_with_callback(hass):
 
     await hass.services.async_call("test_domain", "test_service", blocking=True)
     assert len(runs) == 3
+
+
+def test_valid_entity_id():
+    """Test valid entity ID."""
+    for invalid in [
+        "_light.kitchen",
+        ".kitchen",
+        ".light.kitchen",
+        "light_.kitchen",
+        "light._kitchen",
+        "light.",
+        "light.kitchen__ceiling",
+        "light.kitchen_yo_",
+        "light.kitchen.",
+        "Light.kitchen",
+        "light.Kitchen",
+        "lightkitchen",
+    ]:
+        assert not ha.valid_entity_id(invalid), invalid
+
+    for valid in [
+        "1.a",
+        "1light.kitchen",
+        "a.1",
+        "a.a",
+        "input_boolean.hello_world_0123",
+        "light.1kitchen",
+        "light.kitchen",
+        "light.something_yoo",
+    ]:
+        assert ha.valid_entity_id(valid), valid