Allow raw mqtt payload to be in mqtt publish action (#123900)

* Publish raw rendered mqtt payload as raw for mqtt publish action

* Move check out of try block

* Only try to eval `bytes` is payload starts with supported string

Co-authored-by: Erik Montnemery <erik@montnemery.com>

* Improve docst

* Add `evaluate_bytes` option to publish action

* Rename to `evaluate_payload`

* Update homeassistant/components/mqtt/strings.json

Co-authored-by: Erik Montnemery <erik@montnemery.com>

* Extend test to assert literal_eval is called or not

---------

Co-authored-by: Erik Montnemery <erik@montnemery.com>

homeassistant/components/mqtt/__init__.py

@@ -90,6 +90,7 @@ from .models import (  # noqa: F401
     PublishPayloadType,
     ReceiveMessage,
     ReceivePayloadType,
+    convert_outgoing_mqtt_payload,
 )
 from .subscription import (  # noqa: F401
     EntitySubscription,
@@ -115,6 +116,7 @@ SERVICE_DUMP = "dump"
 
 ATTR_TOPIC_TEMPLATE = "topic_template"
 ATTR_PAYLOAD_TEMPLATE = "payload_template"
+ATTR_EVALUATE_PAYLOAD = "evaluate_payload"
 
 MAX_RECONNECT_WAIT = 300  # seconds
 
@@ -166,6 +168,7 @@ MQTT_PUBLISH_SCHEMA = vol.All(
             vol.Exclusive(ATTR_TOPIC_TEMPLATE, CONF_TOPIC): cv.string,
             vol.Exclusive(ATTR_PAYLOAD, CONF_PAYLOAD): cv.string,
             vol.Exclusive(ATTR_PAYLOAD_TEMPLATE, CONF_PAYLOAD): cv.string,
+            vol.Optional(ATTR_EVALUATE_PAYLOAD): cv.boolean,
             vol.Optional(ATTR_QOS, default=DEFAULT_QOS): valid_qos_schema,
             vol.Optional(ATTR_RETAIN, default=DEFAULT_RETAIN): cv.boolean,
         },
@@ -295,6 +298,7 @@ async def async_setup_entry(hass: HomeAssistant, entry: ConfigEntry) -> bool:
         msg_topic: str | None = call.data.get(ATTR_TOPIC)
         msg_topic_template: str | None = call.data.get(ATTR_TOPIC_TEMPLATE)
         payload: PublishPayloadType = call.data.get(ATTR_PAYLOAD)
+        evaluate_payload: bool = call.data.get(ATTR_EVALUATE_PAYLOAD, False)
         payload_template: str | None = call.data.get(ATTR_PAYLOAD_TEMPLATE)
         qos: int = call.data[ATTR_QOS]
         retain: bool = call.data[ATTR_RETAIN]
@@ -354,6 +358,9 @@ async def async_setup_entry(hass: HomeAssistant, entry: ConfigEntry) -> bool:
             payload = MqttCommandTemplate(
                 template.Template(payload_template, hass)
             ).async_render()
+        elif evaluate_payload:
+            # Convert quoted binary literal to raw data
+            payload = convert_outgoing_mqtt_payload(payload)
 
         if TYPE_CHECKING:
             assert msg_topic is not None

homeassistant/components/mqtt/models.py

@@ -51,6 +51,22 @@ ATTR_THIS = "this"
 type PublishPayloadType = str | bytes | int | float | None
 
 
+def convert_outgoing_mqtt_payload(
+    payload: PublishPayloadType,
+) -> PublishPayloadType:
+    """Ensure correct raw MQTT payload is passed as bytes for publishing."""
+    if isinstance(payload, str) and payload.startswith(("b'", 'b"')):
+        try:
+            native_object = literal_eval(payload)
+        except (ValueError, TypeError, SyntaxError, MemoryError):
+            pass
+        else:
+            if isinstance(native_object, bytes):
+                return native_object
+
+    return payload
+
+
 @dataclass
 class PublishMessage:
     """MQTT Message for publishing."""
@@ -173,22 +189,6 @@ class MqttCommandTemplate:
         variables: TemplateVarsType = None,
     ) -> PublishPayloadType:
         """Render or convert the command template with given value or variables."""
-
-        def _convert_outgoing_payload(
-            payload: PublishPayloadType,
-        ) -> PublishPayloadType:
-            """Ensure correct raw MQTT payload is passed as bytes for publishing."""
-            if isinstance(payload, str):
-                try:
-                    native_object = literal_eval(payload)
-                    if isinstance(native_object, bytes):
-                        return native_object
-
-                except (ValueError, TypeError, SyntaxError, MemoryError):
-                    pass
-
-            return payload
-
         if self._command_template is None:
             return value
 
@@ -210,7 +210,7 @@ class MqttCommandTemplate:
             self._command_template,
         )
         try:
-            return _convert_outgoing_payload(
+            return convert_outgoing_mqtt_payload(
                 self._command_template.async_render(values, parse_result=False)
             )
         except TemplateError as exc:

homeassistant/components/mqtt/services.yaml

@@ -12,6 +12,11 @@ publish:
       example: "The temperature is {{ states('sensor.temperature') }}"
       selector:
         template:
+    evaluate_payload:
+      advanced: true
+      default: false
+      selector:
+        boolean:
     qos:
       advanced: true
       default: 0

homeassistant/components/mqtt/strings.json

@@ -230,6 +230,10 @@
       "name": "Publish",
       "description": "Publishes a message to an MQTT topic.",
       "fields": {
+        "evaluate_payload": {
+          "name": "Evaluate payload",
+          "description": "When `payload` is a Python bytes literal, evaluate the bytes literal and publish the raw data."
+        },
         "topic": {
           "name": "Topic",
           "description": "Topic to publish to."

tests/components/mqtt/test_init.py

@@ -420,6 +420,74 @@ async def test_mqtt_publish_action_call_with_template_payload_renders_template(
     mqtt_mock.reset_mock()
 
 
+@pytest.mark.parametrize(
+    ("attr_payload", "payload", "evaluate_payload", "literal_eval_calls"),
+    [
+        ("b'\\xde\\xad\\xbe\\xef'", b"\xde\xad\xbe\xef", True, 1),
+        ("b'\\xde\\xad\\xbe\\xef'", "b'\\xde\\xad\\xbe\\xef'", False, 0),
+        ("DEADBEEF", "DEADBEEF", False, 0),
+        (
+            "b'\\xde",
+            "b'\\xde",
+            True,
+            1,
+        ),  # Bytes literal is invalid, fall back to string
+    ],
+)
+async def test_mqtt_publish_action_call_with_raw_data(
+    hass: HomeAssistant,
+    mqtt_mock_entry: MqttMockHAClientGenerator,
+    attr_payload: str,
+    payload: str | bytes,
+    evaluate_payload: bool,
+    literal_eval_calls: int,
+) -> None:
+    """Test the mqtt publish action call raw data.
+
+    When `payload` represents a `bytes` object, it should be published
+    as raw data if `evaluate_payload` is set.
+    """
+    mqtt_mock = await mqtt_mock_entry()
+    await hass.services.async_call(
+        mqtt.DOMAIN,
+        mqtt.SERVICE_PUBLISH,
+        {
+            mqtt.ATTR_TOPIC: "test/topic",
+            mqtt.ATTR_PAYLOAD: attr_payload,
+            mqtt.ATTR_EVALUATE_PAYLOAD: evaluate_payload,
+        },
+        blocking=True,
+    )
+    assert mqtt_mock.async_publish.called
+    assert mqtt_mock.async_publish.call_args[0][1] == payload
+
+    with patch(
+        "homeassistant.components.mqtt.models.literal_eval"
+    ) as literal_eval_mock:
+        await hass.services.async_call(
+            mqtt.DOMAIN,
+            mqtt.SERVICE_PUBLISH,
+            {
+                mqtt.ATTR_TOPIC: "test/topic",
+                mqtt.ATTR_PAYLOAD: attr_payload,
+            },
+            blocking=True,
+        )
+        literal_eval_mock.assert_not_called()
+
+        await hass.services.async_call(
+            mqtt.DOMAIN,
+            mqtt.SERVICE_PUBLISH,
+            {
+                mqtt.ATTR_TOPIC: "test/topic",
+                mqtt.ATTR_PAYLOAD: attr_payload,
+                mqtt.ATTR_EVALUATE_PAYLOAD: evaluate_payload,
+            },
+            blocking=True,
+        )
+        assert len(literal_eval_mock.mock_calls) == literal_eval_calls
+
+
 # The use of a payload_template in an mqtt publish action call
 # has been deprecated with HA Core 2024.8.0 and will be removed with HA Core 2025.2.0
 async def test_publish_action_call_with_bad_payload_template(