command-bot: add comments, use timestamp to filter old messages

examples/command_bot.rs

@@ -1,23 +1,31 @@
 use std::sync::Arc;
+use std::time::{SystemTime, UNIX_EPOCH};
 use std::{env, process::exit};
 
-use url::Url;
-
+use js_int::UInt;
 use matrix_sdk::{
     self,
     events::room::message::{MessageEvent, MessageEventContent, TextMessageEventContent},
     AsyncClient, AsyncClientConfig, EventEmitter, Room, SyncSettings,
 };
 use tokio::sync::{Mutex, RwLock};
+use url::Url;
 
 struct CommandBot {
+    /// This clone of the `AsyncClient` will send requests to the server,
+    /// while the other keeps us in sync with the server using `sync_forever`.
     client: Mutex<AsyncClient>,
+    /// A timestamp so we only respond to messages sent after the bot is running.
+    start_time: UInt,
 }
 
 impl CommandBot {
     pub fn new(client: AsyncClient) -> Self {
+        let now = SystemTime::now();
+        let timestamp = now.duration_since(UNIX_EPOCH).unwrap().as_millis();
         Self {
             client: Mutex::new(client),
+            start_time: UInt::new(timestamp as u64).unwrap(),
         }
     }
 }
@@ -25,30 +33,34 @@ impl CommandBot {
 #[async_trait::async_trait]
 impl EventEmitter for CommandBot {
     async fn on_room_message(&self, room: Arc<RwLock<Room>>, event: &MessageEvent) {
-        let msg_body = if let MessageEvent {
+        let (msg_body, timestamp) = if let MessageEvent {
             content: MessageEventContent::Text(TextMessageEventContent { body: msg_body, .. }),
+            origin_server_ts,
             ..
         } = event
         {
-            msg_body.clone()
+            (msg_body.clone(), *origin_server_ts)
         } else {
-            String::new()
+            (String::new(), UInt::min_value())
         };
 
-        if msg_body.contains("!party") {
+        if msg_body.contains("!party") && timestamp > self.start_time {
             let content = MessageEventContent::Text(TextMessageEventContent {
                 body: "🎉🎊🥳 let's PARTY!! 🥳🎊🎉".to_string(),
                 format: None,
                 formatted_body: None,
                 relates_to: None,
             });
-            let room_id = { room.read().await.room_id.clone() };
+            // we clone here to hold the lock for as little time as possible.
+            let room_id = room.read().await.room_id.clone();
 
             println!("sending");
 
             self.client
                 .lock()
                 .await
+                // send our message to the room we found the "!party" command in
+                // the last parameter is an optional Uuid which we don't care about.
                 .room_send(&room_id, content, None)
                 .await
                 .unwrap();
@@ -58,7 +70,6 @@ impl EventEmitter for CommandBot {
     }
 }
 
-#[allow(clippy::for_loop_over_option)]
 async fn login_and_sync(
     homeserver_url: String,
     username: String,
@@ -69,8 +80,9 @@ async fn login_and_sync(
         .disable_ssl_verification();
 
     let homeserver_url = Url::parse(&homeserver_url)?;
+    // create a new AsyncClient with the given homeserver url and config
     let mut client = AsyncClient::new_with_config(homeserver_url, None, client_config).unwrap();
-
+    // add our CommandBot to be notified of incoming messages
     client
         .add_event_emitter(Box::new(CommandBot::new(client.clone())))
         .await;
@@ -86,6 +98,7 @@ async fn login_and_sync(
 
     println!("logged in as {}", username);
 
+    // this keeps state from the server streaming in to CommandBot via the EventEmitter trait
     client.sync_forever(SyncSettings::new(), |_| async {}).await;
 
     Ok(())

examples/login.rs

@@ -21,7 +21,8 @@ impl EventEmitter for EventCallback {
         } = event
         {
             let name = {
-                // any reads or
+                // any reads should be held for the shortest time possible to
+                // avoid dead locks
                 let room = room.read().await;
                 let member = room.members.get(&sender).unwrap();
                 member

src/async_client.rs

@@ -53,6 +53,8 @@ const DEFAULT_SYNC_TIMEOUT: Duration = Duration::from_secs(30);
 
 #[derive(Clone)]
 /// An async/await enabled Matrix client.
+///
+/// All of the state is held in an `Arc` so the `AsyncClient` can be cloned freely.
 pub struct AsyncClient {
     /// The URL of the homeserver to connect to.
     homeserver: Url,

src/event_emitter/mod.rs

@@ -50,28 +50,29 @@ use tokio::sync::RwLock;
 ///     },
 ///     AsyncClient, AsyncClientConfig, EventEmitter, Room, SyncSettings,
 /// };
-/// use tokio::sync::Mutex;
+/// use tokio::sync::RwLock;
 ///
 /// struct EventCallback;
 ///
 /// #[async_trait::async_trait]
 /// impl EventEmitter for EventCallback {
-///     async fn on_room_message(&self, room: &Room, event: &MessageEvent) {
+///     async fn on_room_message(&self, room: Arc<RwLock<Room>>, event: &MessageEvent) {
 ///         if let MessageEvent {
 ///             content: MessageEventContent::Text(TextMessageEventContent { body: msg_body, .. }),
 ///             sender,
 ///             ..
 ///         } = event
 ///         {
-///             let member = room.members.get(&sender).unwrap();
-///             println!(
-///                 "{}: {}",
-///                 member
-///                     .display_name
-///                     .as_ref()
-///                     .unwrap_or(&sender.to_string()),
-///                 msg_body
-///             );
+///             let name = {
+///                let room = room.read().await;
+///                let member = room.members.get(&sender).unwrap();
+///                member
+///                    .display_name
+///                    .as_ref()
+///                    .map(ToString::to_string)
+///                    .unwrap_or(sender.to_string())
+///            };
+///             println!("{}: {}", name, msg_body);
 ///         }
 ///     }
 /// }