Add Button component

Author: medusalix

src/homeassistant/button.rs

@@ -0,0 +1,40 @@
+//! Tools for publishing a [Home Assistant button](https://www.home-assistant.io/integrations/button.mqtt/).
+use core::ops::Deref;
+
+use serde::Serialize;
+
+use crate::{homeassistant::Component, Error, Topic};
+
+/// The type of button.
+#[derive(Serialize)]
+#[serde(rename_all = "snake_case")]
+#[allow(missing_docs)]
+pub enum ButtonClass {
+    Identify,
+    Restart,
+    Update,
+}
+
+/// A button that can be pressed.
+#[derive(Serialize)]
+pub struct Button {
+    /// The type of button.
+    pub device_class: Option<ButtonClass>,
+}
+
+impl Component for Button {
+    type State = ();
+
+    fn platform() -> &'static str {
+        "button"
+    }
+
+    async fn publish_state<T: Deref<Target = str>>(
+        &self,
+        _topic: &Topic<T>,
+        _state: Self::State,
+    ) -> Result<(), Error> {
+        // Buttons don't have a state
+        Err(Error::Invalid)
+    }
+}

src/homeassistant/mod.rs

@@ -50,6 +50,7 @@ use crate::{
 };
 
 pub mod binary_sensor;
+pub mod button;
 pub mod light;
 pub mod sensor;
 mod ser;