Implement notifications

Cargo.toml

@@ -10,17 +10,22 @@ dry_run = [] # will prevent some actions like shutting down
 
 [dependencies]
 anyhow = "1.0.69"
+base64 = "0.21.0"
 directories = "4.0.1"
 env_logger = "0.10.0"
 exitcode = "1.1.2"
+image = "0.24.5"
 json = "0.12.4"
 lazy_static = "1.4.0"
 log = "0.4.17"
 mac_address = "1.1.4"
+notify-rust = { version = "4.8.0", features = ["images"] }
 rand = "0.8.5"
 regex = "1.7.1"
 rumqttc = "0.20.0"
 serde = { version = "1.0.152", features = ["derive"] }
+serde_json = "1.0.93"
 tokio = { version = "1.25.0", features = ["full"] }
 toml = "0.7.2"
 validator = { version = "0.16.0", features = ["derive"] }
+void = "1.0.2"

README.md

@@ -4,8 +4,8 @@
 ## Features
 - [ ] Fallback MQTT broker address
 - [x] Command buttons
-- [ ] Notifications
-  - [ ] Actions
+- [x] Notifications
+  - [x] Actions
 - [ ] System stats
   - [ ] CPU usage
   - [ ] RAM usage
@@ -14,5 +14,11 @@
 - [ ] PipeWire
 - [ ] File watcher
 
+Ideas:
+
+- Camera video stream
+- Idle time
+
 ## License
+
 Hassliebe is licensed under the [Blue Oak Model License 1.0.0](/LICENSE.md).

src/config.rs

@@ -5,13 +5,12 @@ use std::io::{ErrorKind, Read, Write};
 use std::path::Path;
 
 use anyhow::{bail, Context, Result};
-use rand::distributions::Alphanumeric;
-use rand::Rng;
 use regex::Regex;
 use serde::{Deserialize, Serialize};
 use validator::{Validate, ValidationError};
 
 use crate::modules;
+use crate::util::generate_alphanumeric_id;
 
 #[derive(Serialize, Deserialize, Validate)]
 pub struct Mqtt {
@@ -37,7 +36,16 @@ pub struct Internal {
 }
 
 #[derive(Serialize, Deserialize, Validate)]
-pub(crate) struct Config {
+pub struct Modules {
+    #[validate]
+    pub buttons: Option<modules::buttons::Config>,
+
+    #[validate]
+    pub notifications: Option<modules::notifications::Config>,
+}
+
+#[derive(Serialize, Deserialize, Validate)]
+pub struct Config {
     #[validate(custom = "validate_unique_id")]
     pub unique_id: String,
 
@@ -48,15 +56,15 @@ pub(crate) struct Config {
     #[validate]
     pub mqtt: Mqtt,
 
+    #[validate]
+    pub modules: Modules,
+
     #[serde(rename = "DO_NOT_CHANGE")]
     #[validate]
     pub internal: Internal,
-
-    #[validate]
-    pub command_buttons: Option<modules::command_buttons::Config>,
 }
 
-pub(crate) fn validate_unique_id(value: &str) -> Result<(), ValidationError> {
+pub fn validate_unique_id(value: &str) -> Result<(), ValidationError> {
     if Regex::new(r"^[a-zA-Z0-9]+(_[a-zA-Z0-9]+)*$").unwrap().is_match(value) {
         Ok(())
     } else {
@@ -64,10 +72,6 @@ pub(crate) fn validate_unique_id(value: &str) -> Result<(), ValidationError> {
     }
 }
 
-fn generate_unique_id() -> String {
-    rand::thread_rng().sample_iter(&Alphanumeric).take(12).map(char::from).collect()
-}
-
 fn create_example_config() -> Config {
     Config {
         unique_id: "my_pc".to_owned(),
@@ -79,16 +83,19 @@ fn create_example_config() -> Config {
             credentials: None,
         },
         internal: Internal {
-            stable_id: generate_unique_id(),
+            stable_id: generate_alphanumeric_id(12),
         },
-        command_buttons: Some(modules::command_buttons::Config {
+        modules: Modules {
+            buttons: Some(modules::buttons::Config {
                 enabled: false,
                 buttons: Vec::new(),
-        })
+            }),
+            notifications: Some(modules::notifications::Config { enabled: false }),
+        },
     }
 }
 
-pub(crate) fn load(config_file_path: &Path) -> Result<Option<Config>> {
+pub fn load(config_file_path: &Path) -> Result<Option<Config>> {
     match File::open(config_file_path) {
         Ok(mut file) => {
             log::info!("Reading config file: {}", config_file_path.to_string_lossy());
@@ -108,7 +115,6 @@ pub(crate) fn load(config_file_path: &Path) -> Result<Option<Config>> {
             }
 
             let mut file = File::create(config_file_path).context("while creating the default config file")?;
-
             let default = toml::to_string::<Config>(&create_example_config()).expect("create_example_config() should be valid");
 
             file.write_all(default.as_bytes())?;

src/main.rs

@@ -1,15 +1,17 @@
 use std::collections::{HashMap, HashSet};
 use std::path::{Path, PathBuf};
 use std::process::exit;
+use std::sync::Arc;
 
 use anyhow::{anyhow, Result};
 
-use crate::modules::{ModuleContext, ModuleContextMqtt};
+use crate::modules::{InitializationContext, ModuleContext, ModuleContextMqtt};
 use crate::mqtt::OwnedTopicsService;
 
 mod config;
 mod modules;
 mod mqtt;
+mod util;
 
 struct Paths {
     data_directory: Box<Path>,
@@ -58,18 +60,21 @@ async fn main() -> Result<()> {
 
     let owned_topics_service = OwnedTopicsService::new(&paths.data_directory).await?;
 
-    let mut module_context = ModuleContext {
-        config: &config,
+    let mut initialization_context = InitializationContext {
+        owned_mqtt_topics: HashSet::new(),
+        message_handler_by_mqtt_topic: HashMap::new(),
+
+        full: Arc::new(ModuleContext {
+            config,
             mqtt: ModuleContextMqtt {
-            client: &mqtt_client,
-            availability_topic: availability_topic.as_str(),
-            discovery_device_object: &discovery_device_object,
-            message_handler_by_topic: HashMap::new(),
-            owned_topics: HashSet::new(),
+                client: mqtt_client,
+                availability_topic,
+                discovery_device_object,
             },
+        }),
     };
 
-    modules::init_all(&mut module_context).await?;
+    modules::init_all(&mut initialization_context).await?;
 
-    mqtt::start_communication(&module_context, event_loop, owned_topics_service).await
+    mqtt::start_communication(&initialization_context, event_loop, owned_topics_service).await
 }

src/modules/buttons.rs

@@ -4,14 +4,13 @@ use tokio::process::Command;
 use validator::Validate;
 
 use crate::config::validate_unique_id;
+use crate::modules::InitializationContext;
 
-use super::ModuleContext;
-
-const MODULE_ID: &str = "power";
+const MODULE_ID: &str = "buttons";
 const BUTTON_TRIGGER_TEXT: &str = "press";
 
 #[derive(Serialize, Deserialize, Validate, Clone)]
-pub(crate) struct ButtonConfig {
+pub struct ButtonConfig {
     #[validate(custom = "validate_unique_id")]
     pub id: String,
 
@@ -26,7 +25,7 @@ pub(crate) struct ButtonConfig {
 }
 
 #[derive(Serialize, Deserialize, Validate)]
-pub(crate) struct Config {
+pub struct Config {
     #[serde(default)]
     pub enabled: bool,
 
@@ -34,10 +33,11 @@ pub(crate) struct Config {
     pub buttons: Vec<ButtonConfig>,
 }
 
-pub(crate) async fn init(context: &mut ModuleContext<'_>) -> Result<()> {
-    let config = match &context.config.command_buttons {
+pub async fn init(context: &mut InitializationContext) -> Result<()> {
+    let full_context = context.get_full();
+    let config = match &full_context.config.modules.buttons {
         Some(c) if c.enabled => c,
-        _ => return Ok(())
+        _ => return Ok(()),
     };
 
     log::info!("Initializing…");
@@ -48,18 +48,17 @@ pub(crate) async fn init(context: &mut ModuleContext<'_>) -> Result<()> {
     Ok(())
 }
 
-async fn init_command_button(context: &mut ModuleContext<'_>, config: ButtonConfig) -> Result<()> {
-    let entity_id = context.get_entity_id(MODULE_ID, &config.id);
-    let command_topic = context.mqtt.get_topic("button", &entity_id, "trigger");
+async fn init_command_button(context: &mut InitializationContext, config: ButtonConfig) -> Result<()> {
+    let entity_id = context.full.get_entity_id(MODULE_ID, &config.id);
+    let command_topic = context.full.mqtt.get_homeassistant_topic("button", &entity_id, "trigger");
 
     context
-        .mqtt
-        .send_retained_message(
-            context.mqtt.get_topic("button", &entity_id, "config"),
+        .send_retained_mqtt_message(
+            context.full.mqtt.get_homeassistant_topic("button", &entity_id, "config"),
             json::stringify(json::object! {
-                "availability_topic": context.mqtt.availability_topic,
+                "availability_topic": context.full.mqtt.availability_topic.clone(),
                 "command_topic": command_topic.as_str(),
-                "device": context.mqtt.discovery_device_object.clone(),
+                "device": context.full.mqtt.discovery_device_object.clone(),
                 "icon": "mdi:power",
                 "name": config.name,
                 "payload_press": BUTTON_TRIGGER_TEXT,
@@ -69,7 +68,7 @@ async fn init_command_button(context: &mut ModuleContext<'_>, config: ButtonConf
         )
         .await?;
 
-    context.mqtt.subscribe(command_topic, move |text| {
+    context.subscribe_mqtt_topic(command_topic, move |text| {
         if text == BUTTON_TRIGGER_TEXT {
             run_command(config.command.clone(), config.run_in_shell);
         } else {

src/modules/mod.rs

@@ -1,53 +1,66 @@
 use std::collections::{HashMap, HashSet};
+use std::sync::Arc;
 
 use anyhow::Result;
 use json::JsonValue;
 use rumqttc::{AsyncClient as MqttClient, ClientError, QoS};
 
-pub mod command_buttons;
+pub mod buttons;
+pub mod notifications;
 
-type MqttMessageHandler<'a> = dyn Fn(&str) -> Result<()> + 'a;
+type MqttMessageHandler = dyn Fn(&str) -> Result<()>;
 
-pub struct ModuleContextMqtt<'a> {
-    pub discovery_device_object: &'a JsonValue,
-    pub availability_topic: &'a str,
-    pub client: &'a MqttClient,
-    pub message_handler_by_topic: HashMap<String, Box<MqttMessageHandler<'a>>>,
+pub struct ModuleContextMqtt {
+    pub discovery_device_object: JsonValue,
+    pub availability_topic: String,
+    pub client: MqttClient,
+}
 
+pub struct InitializationContext {
     // Owned topics are topics which a retained message was sent into.
-    pub owned_topics: HashSet<String>,
+    pub owned_mqtt_topics: HashSet<String>,
+    pub message_handler_by_mqtt_topic: HashMap<String, Box<MqttMessageHandler>>,
+
+    pub full: Arc<ModuleContext>,
 }
 
-pub(crate) struct ModuleContext<'a> {
-    pub config: &'a super::config::Config,
-    pub mqtt: ModuleContextMqtt<'a>,
+impl InitializationContext {
+    fn subscribe_mqtt_topic<F: Fn(&str) -> Result<()> + 'static>(&mut self, topic: impl Into<String>, handler: F) {
+        self.message_handler_by_mqtt_topic.insert(topic.into(), Box::new(handler));
+    }
+
+    async fn send_retained_mqtt_message(&mut self, topic: impl Into<String>, message: impl Into<String>) -> std::result::Result<(), ClientError> {
+        let topic = topic.into();
+        let message = message.into();
+
+        self.owned_mqtt_topics.insert(topic.to_owned());
+        self.full.mqtt.client.publish(topic, QoS::AtLeastOnce, true, message).await
+    }
+
+    fn get_full(&self) -> Arc<ModuleContext> {
+        self.full.clone()
+    }
 }
 
-impl<'a> ModuleContext<'a> {
+pub struct ModuleContext {
+    pub config: super::config::Config,
+    pub mqtt: ModuleContextMqtt,
+}
+
+impl ModuleContext {
     fn get_entity_id(&self, module_id: &str, sub_id: &str) -> String {
         format!("{}_{}_{}", self.config.unique_id, module_id, sub_id)
     }
 }
 
-impl<'a> ModuleContextMqtt<'a> {
-    fn get_topic(&self, component_type: &str, entity_id: &str, suffix: &str) -> String {
+impl ModuleContextMqtt {
+    fn get_homeassistant_topic(&self, component_type: &str, entity_id: &str, suffix: &str) -> String {
         format!("homeassistant/{}/{}/{}", component_type, entity_id, suffix)
     }
-
-    fn subscribe<F: Fn(&str) -> Result<()> + 'a>(&mut self, topic: impl Into<String>, handler: F) {
-        self.message_handler_by_topic.insert(topic.into(), Box::new(handler));
-    }
-
-    async fn send_retained_message(&mut self, topic: impl Into<String>, message: impl Into<String>) -> std::result::Result<(), ClientError> {
-        let topic = topic.into();
-        let message = message.into();
-
-        self.owned_topics.insert(topic.to_owned());
-        self.client.publish(topic, QoS::AtLeastOnce, true, message).await
-    }
 }
 
-pub(crate) async fn init_all(context: &mut ModuleContext<'_>) -> Result<()> {
-    command_buttons::init(context).await?;
+pub async fn init_all(context: &mut InitializationContext) -> Result<()> {
+    buttons::init(context).await?;
+    notifications::init(context).await?;
     Ok(())
 }

src/modules/notifications.rs

@@ -0,0 +1,221 @@
+use std::collections::HashMap;
+use std::sync::Arc;
+
+use anyhow::{Context, Result};
+use base64::Engine;
+use notify_rust::Hint;
+use rumqttc::QoS;
+use serde::{Deserialize, Serialize};
+use tokio::task::spawn_blocking;
+use validator::Validate;
+
+use crate::modules::{InitializationContext, ModuleContext};
+use crate::util::{generate_alphanumeric_id, hash_string_to_u32, spawn_nonessential};
+
+const MODULE_ID: &str = "notifications";
+
+#[derive(Serialize, Deserialize, Validate)]
+pub struct Config {
+    #[serde(default)]
+    pub enabled: bool,
+}
+
+#[derive(Deserialize, Default)]
+#[serde(rename_all = "snake_case")]
+pub enum NotificationTimeout {
+    Never,
+
+    #[default]
+    Default,
+
+    Ms(u16),
+}
+
+#[derive(Deserialize, Default)]
+#[serde(rename_all = "snake_case")]
+pub enum NotificationUrgency {
+    Low,
+
+    #[default]
+    Normal,
+    Critical,
+}
+
+impl From<NotificationUrgency> for notify_rust::Urgency {
+    fn from(value: NotificationUrgency) -> Self {
+        match value {
+            NotificationUrgency::Low => notify_rust::Urgency::Low,
+            NotificationUrgency::Normal => notify_rust::Urgency::Normal,
+            NotificationUrgency::Critical => notify_rust::Urgency::Critical,
+        }
+    }
+}
+
+#[derive(Deserialize, Validate)]
+pub struct NotificationMessage {
+    /// Using the ID of an existing notification will replace the old notification.
+    #[validate(length(min = 1))]
+    id: Option<String>,
+
+    #[serde(default)]
+    timeout: NotificationTimeout,
+
+    #[serde(default)]
+    urgency: NotificationUrgency,
+
+    /// Usually used as the title of the notification.
+    #[validate(length(min = 1))]
+    summary_text: String,
+
+    /// Basic HTML is usually supported.
+    #[validate(length(min = 1))]
+    long_content: Option<String>,
+
+    /// If the notification server supports persisting notifications across sessions, this will prevent it from doing so for this notification.
+    #[serde(default)]
+    transient: bool,
+
+    /// Padded base64-encoded image
+    encoded_image: Option<String>,
+
+    #[serde(default)]
+    actions: HashMap<String, String>,
+}
+
+pub async fn init(context: &mut InitializationContext) -> Result<()> {
+    let full_context = context.get_full();
+    let _config = match &full_context.config.modules.notifications {
+        Some(c) if c.enabled => c,
+        _ => return Ok(()),
+    };
+
+    log::info!("Initializing…");
+
+    let full_context = context.get_full();
+    context.subscribe_mqtt_topic(format!("{}/{}/simple", context.full.config.unique_id, MODULE_ID), move |text| {
+        let (summary_text, long_content) = text.split_once('\n').unwrap_or((text, ""));
+
+        tokio::spawn(handle_notification_message(
+            full_context.clone(),
+            NotificationMessage {
+                id: None,
+                transient: true,
+                summary_text: summary_text.to_owned(),
+                long_content: if long_content.is_empty() { None } else { Some(long_content.to_owned()) },
+                timeout: NotificationTimeout::default(),
+                urgency: NotificationUrgency::default(),
+                encoded_image: None,
+                actions: HashMap::new(),
+            },
+        ));
+
+        Ok(())
+    });
+
+    let full_context = context.get_full();
+    context.subscribe_mqtt_topic(format!("{}/{}/json", context.full.config.unique_id, MODULE_ID), move |text| {
+        let message = serde_json::from_str::<NotificationMessage>(text);
+
+        match message {
+            Err(error) => log::error!("Could not deserialize message: {}", error),
+
+            Ok(message) => {
+                spawn_nonessential(handle_notification_message(full_context.clone(), message));
+            }
+        }
+
+        Ok(())
+    });
+
+    context.subscribe_mqtt_topic(format!("{}/{}/close", context.full.config.unique_id, MODULE_ID), move |id| {
+        spawn_nonessential(close_notification(id.to_owned()));
+
+        Ok(())
+    });
+
+    Ok(())
+}
+
+async fn handle_notification_message(context: Arc<ModuleContext>, message: NotificationMessage) -> Result<()> {
+    let mut notification = notify_rust::Notification::new();
+    let id = message.id.unwrap_or_else(|| generate_alphanumeric_id(10));
+    let internal_id = hash_string_to_u32(id.as_str());
+
+    notification.id(internal_id);
+    notification.summary(message.summary_text.as_str());
+    notification.urgency(message.urgency.into());
+    notification.hint(Hint::Transient(message.transient));
+    notification.timeout(match message.timeout {
+        NotificationTimeout::Default => -1,
+        NotificationTimeout::Never => 0,
+        NotificationTimeout::Ms(ms) => ms.into(),
+    });
+
+    for (action_id, label) in message.actions {
+        notification.action(&action_id, &label);
+    }
+
+    if let Some(encoded_image) = message.encoded_image {
+        let image_data = base64::engine::general_purpose::STANDARD_NO_PAD
+            .decode(encoded_image)
+            .context("while decoding the base64 image")?;
+
+        let image = image::load_from_memory(&image_data).context("while reading the image")?;
+
+        notification.image_data(image.try_into()?);
+    }
+
+    if let Some(long_content) = message.long_content {
+        notification.body(long_content.as_str());
+    }
+
+    log::debug!("Showing notification: {}", id);
+    let handle = notification.show_async().await?;
+
+    {
+        let context = context.clone();
+
+        spawn_blocking(move || {
+            handle.wait_for_action(|action_id| {
+                spawn_nonessential(send_notification_action_message(
+                    context,
+                    id.clone(),
+                    if action_id == "__closed" { "closed".to_owned() } else { action_id.to_owned() },
+                ));
+            });
+        });
+    }
+
+    Ok(())
+}
+
+async fn close_notification(id: String) -> Result<()> {
+    // We create a new notification because otherwise we would need to store old notification handles
+    // and notify-rust does not expose a method to close a notification by ID.
+
+    let internal_id = hash_string_to_u32(&id);
+    let mut notification = notify_rust::Notification::new();
+
+    notification.id(internal_id);
+
+    log::debug!("Closing notification: {}", id);
+    let handle = notification.show_async().await?;
+    handle.close();
+
+    Ok(())
+}
+
+async fn send_notification_action_message(context: Arc<ModuleContext>, notification_id: String, action_id: String) -> Result<()> {
+    context
+        .mqtt
+        .client
+        .publish(
+            format!("{}/{}/action/{}", context.config.unique_id, MODULE_ID, notification_id),
+            QoS::ExactlyOnce,
+            false,
+            action_id,
+        )
+        .await?;
+
+    Ok(())
+}

src/mqtt.rs

@@ -12,23 +12,25 @@ use tokio::fs::{File, OpenOptions};
 use tokio::io::{AsyncReadExt, AsyncSeekExt, AsyncWriteExt};
 use tokio::time::{Instant, sleep};
 
-use crate::modules::ModuleContext;
+use crate::modules::InitializationContext;
 
 use super::config;
 
-pub(crate) async fn create_client(config: &config::Config, availability_topic: &str) -> Result<(MqttClient, EventLoop)> {
+pub async fn create_client(config: &config::Config, availability_topic: &str) -> Result<(MqttClient, EventLoop)> {
     let mut options = MqttOptions::new(&config.internal.stable_id, config.mqtt.host.to_owned(), config.mqtt.port);
     options.set_clean_session(true);
     options.set_keep_alive(Duration::from_secs(5));
     options.set_last_will(LastWill::new(availability_topic, "offline", QoS::AtLeastOnce, true));
 
+    options.set_max_packet_size(usize::MAX, usize::MAX);
+
     let (mqtt_client, event_loop) = MqttClient::new(options, 10);
     mqtt_client.publish(availability_topic, QoS::AtLeastOnce, true, "online").await?;
 
     Ok((mqtt_client, event_loop))
 }
 
-pub(crate) fn create_discovery_device_object(config: &config::Config) -> JsonValue {
+pub fn create_discovery_device_object(config: &config::Config) -> JsonValue {
     json::object! {
         "connections": if config.announce_mac_address {
             mac_address::get_mac_address().unwrap_or(None).map(|a| json::array![["mac", a.to_string()]]).unwrap_or(json::array![])
@@ -45,7 +47,7 @@ pub struct OwnedTopicsService {
 }
 
 impl OwnedTopicsService {
-    pub(crate) async fn new(data_directory_path: &Path) -> Result<OwnedTopicsService> {
+    pub async fn new(data_directory_path: &Path) -> Result<OwnedTopicsService> {
         let path = data_directory_path.join("owned_topics");
         let mut file = OpenOptions::new().write(true).read(true).create(true).open(path).await?;
 
@@ -57,11 +59,11 @@ impl OwnedTopicsService {
         Ok(OwnedTopicsService { file, old_topics })
     }
 
-    pub(crate) async fn clear_old_and_save_new(mut self, mqtt_client: &MqttClient, new_topics: &HashSet<String>) -> Result<()> {
+    pub async fn clear_old_and_save_new(mut self, mqtt_client: &MqttClient, new_topics: &HashSet<String>) -> Result<()> {
         let unused_topics = self.old_topics.difference(new_topics).map(|s| s.to_owned()).collect::<Vec<_>>();
 
         log::info!(
-            "{} unused owned topics will be cleared. Now using {} owned topics.",
+            "{} unused owned topic(s) will be cleared. Now using {} owned topic(s).",
             unused_topics.len(),
             new_topics.len()
         );
@@ -100,17 +102,21 @@ const FAST_RETRYING_INTERVAL_MS: u64 = 500;
 const FAST_RETRYING_LIMIT_SECONDS: u64 = 15;
 const SLOW_RETRYING_INTERVAL_SECONDS: u64 = 5;
 
-pub(crate) async fn start_communication(context: &ModuleContext<'_>, mut event_loop: EventLoop, owned_topics_service: OwnedTopicsService) -> Result<()> {
-    log::info!("Connecting to MQTT broker at {}:{}", context.config.mqtt.host, context.config.mqtt.port);
+pub async fn start_communication(context: &InitializationContext, mut event_loop: EventLoop, owned_topics_service: OwnedTopicsService) -> Result<()> {
+    log::info!(
+        "Connecting to MQTT broker at {}:{}",
+        context.full.config.mqtt.host,
+        context.full.config.mqtt.port
+    );
 
-    if !context.mqtt.message_handler_by_topic.is_empty() {
+    if !context.message_handler_by_mqtt_topic.is_empty() {
         context
+            .full
             .mqtt
             .client
             .subscribe_many(
                 context
-                    .mqtt
-                    .message_handler_by_topic
+                    .message_handler_by_mqtt_topic
                     .keys()
                     .map(|k| SubscribeFilter::new(k.to_owned(), QoS::AtLeastOnce)),
             )
@@ -173,8 +179,7 @@ pub(crate) async fn start_communication(context: &ModuleContext<'_>, mut event_l
                     }
 
                     if let Some(service) = owned_topics_service.take() {
-                        service.clear_old_and_save_new(context.mqtt.client, &context.mqtt.owned_topics)
-                            .await?;
+                        service.clear_old_and_save_new(&context.full.mqtt.client, &context.owned_mqtt_topics).await?;
                     }
 
                     connection_state = ConnectionState::Connected;
@@ -183,7 +188,7 @@ pub(crate) async fn start_communication(context: &ModuleContext<'_>, mut event_l
                 Incoming(Packet::Publish(message)) => {
                     let text = std::str::from_utf8(&message.payload)?;
 
-                    if let Some(handler) = context.mqtt.message_handler_by_topic.get(message.topic.as_str()) {
+                    if let Some(handler) = context.message_handler_by_mqtt_topic.get(message.topic.as_str()) {
                         handler(text)?;
                     }
                 }

src/util.rs

@@ -0,0 +1,27 @@
+use std::collections::hash_map::DefaultHasher;
+use std::future::Future;
+use std::hash::{Hash, Hasher};
+
+use anyhow::Result;
+use rand::distributions::Alphanumeric;
+use rand::Rng;
+use tokio::task::JoinHandle;
+
+#[inline]
+pub fn spawn_nonessential(future: impl Future<Output=Result<()>> + Send + 'static) -> JoinHandle<()> {
+    tokio::spawn(async {
+        if let Err(error) = future.await {
+            log::error!("{:#}", error)
+        }
+    })
+}
+
+pub fn generate_alphanumeric_id(length: usize) -> String {
+    rand::thread_rng().sample_iter(&Alphanumeric).take(length).map(char::from).collect()
+}
+
+pub fn hash_string_to_u32(string: &str) -> u32 {
+    let mut hasher = DefaultHasher::new();
+    string.hash(&mut hasher);
+    (hasher.finish() / 2) as u32
+}