autojoin: filter room based on ID

src/autojoin.rs

@@ -3,17 +3,19 @@ use std::time::Duration;
 use matrix_sdk::{
     self, async_trait,
     events::{room::member::MemberEventContent, StrippedStateEvent},
+    identifiers::RoomId,
     Client, EventEmitter, RoomState,
 };
 use tokio::time::sleep;
 
 pub struct AutoJoinHandler {
     client: Client,
+    room_id: RoomId,
 }
 
 impl AutoJoinHandler {
-    pub fn new(client: Client) -> Self {
+    pub fn new(client: Client, room_id: RoomId) -> Self {
-        Self { client }
+        Self { client, room_id }
     }
 }
 
@@ -30,7 +32,23 @@ impl EventEmitter for AutoJoinHandler {
         }
 
         if let RoomState::Invited(room) = room {
-            // TODO: only join room if it's the room specified in the configuration
+            let room_id = room.room_id();
+            let room_name = room.display_name().await;
+            println!(
+                "Received invitation for room `{}`: `{}`",
+                room_id, room_name
+            );
+
+            if room_id != &self.room_id {
+                println!(
+                    "Bot isn't authorized to join room `{}`, declining invitation",
+                    room_id
+                );
+                // leaving a room is equivalent to rejecting the invitation, as per
+                // https://matrix.org/docs/spec/client_server/r0.6.0#post-matrix-client-r0-rooms-roomid-leave
+                self.client.leave_room(room_id).await.unwrap();
+                return;
+            }
 
             println!("Autojoining room {}", room.room_id());
             let mut delay = 2;

src/bot.rs

@@ -32,7 +32,10 @@ impl BadNewsBot {
         load_or_init_session(&self).await?;
 
         self.client
-            .add_event_emitter(Box::new(AutoJoinHandler::new(self.client.clone())))
+            .add_event_emitter(Box::new(AutoJoinHandler::new(
+                self.client.clone(),
+                self.config.room_id.clone(),
+            )))
             .await;
 
         Ok(())

src/main.rs

@@ -5,6 +5,7 @@ use std::{
 };
 
 use clap::Clap;
+use matrix_sdk::identifiers::RoomId;
 use serde::Deserialize;
 use thiserror::Error;
 use url::Url;
@@ -41,6 +42,9 @@ pub struct Config {
     password: String,
     /// Path to a directory where the bot will store Matrix state and current session information.
     state_dir: PathBuf,
+    /// ID of the Matrix room where the bot should post messages. The bot will only accept
+    /// invitations to this room.
+    room_id: RoomId,
 }
 
 #[tokio::main]