correct MQTT subscription filter (#7269)

* correct MQTT subscription filter

* wildcard handling (#) fixed

* wildcard handling (#) fixed

* added tests for topic subscription like +/something/#

* function names changed (line too long)

* using raw strings for regular expression
import order changed

homeassistant/components/mqtt/__init__.py

@@ -10,6 +10,7 @@ import os
 import socket
 import time
 import ssl
+import re
 import requests.certs
 
 import voluptuous as vol
@@ -639,12 +640,20 @@ def _raise_on_error(result):
 
 def _match_topic(subscription, topic):
     """Test if topic matches subscription."""
+    reg_ex_parts = []
+    suffix = ""
     if subscription.endswith('#'):
-        return (subscription[:-2] == topic or
-                topic.startswith(subscription[:-1]))
-
+        subscription = subscription[:-2]
+        suffix = "(.*)"
     sub_parts = subscription.split('/')
-    topic_parts = topic.split('/')
+    for sub_part in sub_parts:
+        if sub_part == "+":
+            reg_ex_parts.append(r"([^\/]+)")
+        else:
+            reg_ex_parts.append(sub_part)
 
-    return (len(sub_parts) == len(topic_parts) and
-            all(a == b for a, b in zip(sub_parts, topic_parts) if a != '+'))
+    reg_ex = "^" + (r'\/'.join(reg_ex_parts)) + suffix + "$"
+
+    reg = re.compile(reg_ex)
+
+    return reg.match(topic) is not None

tests/components/mqtt/test_init.py

@@ -209,6 +209,46 @@ class TestMQTT(unittest.TestCase):
         self.hass.block_till_done()
         self.assertEqual(0, len(self.calls))
 
+    def test_subscribe_topic_level_wildcard_and_wildcard_root_topic(self):
+        """Test the subscription of wildcard topics."""
+        mqtt.subscribe(self.hass, '+/test-topic/#', self.record_calls)
+
+        fire_mqtt_message(self.hass, 'hi/test-topic', 'test-payload')
+
+        self.hass.block_till_done()
+        self.assertEqual(1, len(self.calls))
+        self.assertEqual('hi/test-topic', self.calls[0][0])
+        self.assertEqual('test-payload', self.calls[0][1])
+
+    def test_subscribe_topic_level_wildcard_and_wildcard_subtree_topic(self):
+        """Test the subscription of wildcard topics."""
+        mqtt.subscribe(self.hass, '+/test-topic/#', self.record_calls)
+
+        fire_mqtt_message(self.hass, 'hi/test-topic/here-iam', 'test-payload')
+
+        self.hass.block_till_done()
+        self.assertEqual(1, len(self.calls))
+        self.assertEqual('hi/test-topic/here-iam', self.calls[0][0])
+        self.assertEqual('test-payload', self.calls[0][1])
+
+    def test_subscribe_topic_level_wildcard_and_wildcard_level_no_match(self):
+        """Test the subscription of wildcard topics."""
+        mqtt.subscribe(self.hass, '+/test-topic/#', self.record_calls)
+
+        fire_mqtt_message(self.hass, 'hi/here-iam/test-topic', 'test-payload')
+
+        self.hass.block_till_done()
+        self.assertEqual(0, len(self.calls))
+
+    def test_subscribe_topic_level_wildcard_and_wildcard_no_match(self):
+        """Test the subscription of wildcard topics."""
+        mqtt.subscribe(self.hass, '+/test-topic/#', self.record_calls)
+
+        fire_mqtt_message(self.hass, 'hi/another-test-topic', 'test-payload')
+
+        self.hass.block_till_done()
+        self.assertEqual(0, len(self.calls))
+
     def test_subscribe_binary_topic(self):
         """Test the subscription to a binary topic."""
         mqtt.subscribe(self.hass, 'test-topic', self.record_calls,