add send binary for posting messages to matrix rooms

src/bin/send.rs

@@ -0,0 +1,64 @@
+use std::path::Path;
+
+use anyhow::Context;
+use matrix_sdk::{
+    Client,
+    authentication::matrix::MatrixSession,
+    ruma::{OwnedRoomId, events::room::message::RoomMessageEventContent},
+};
+use serde::Deserialize;
+use tokio::fs;
+
+#[derive(Debug, Deserialize)]
+struct PersistedSession {
+    homeserver: String,
+    db_path: std::path::PathBuf,
+    user_session: MatrixSession,
+}
+
+const STATE_DIR: &str = "/persist/damocles-lab/state";
+
+#[tokio::main]
+async fn main() -> anyhow::Result<()> {
+    let args: Vec<String> = std::env::args().collect();
+    if args.len() < 3 {
+        eprintln!("usage: send <room_id> <message | ->");
+        eprintln!("  send '!room:server' 'hello world'");
+        eprintln!("  echo 'hello' | send '!room:server' -");
+        std::process::exit(1);
+    }
+
+    let room_id: OwnedRoomId = args[1].parse().context("invalid room ID")?;
+    let message = if args[2] == "-" {
+        use std::io::Read;
+        let mut buf = String::new();
+        std::io::stdin().read_to_string(&mut buf)?;
+        buf.trim().to_owned()
+    } else {
+        args[2..].join(" ")
+    };
+
+    let session_file = Path::new(STATE_DIR).join("session.json");
+    let data = fs::read_to_string(&session_file)
+        .await
+        .context("no session file - run the daemon first to log in")?;
+    let session: PersistedSession = serde_json::from_str(&data)?;
+
+    let client = Client::builder()
+        .homeserver_url(&session.homeserver)
+        .sqlite_store(&session.db_path, None)
+        .build()
+        .await?;
+
+    client.restore_session(session.user_session).await?;
+
+    // need at least one sync so the client knows about joined rooms
+    client.sync_once(matrix_sdk::config::SyncSettings::default()).await?;
+
+    let room = client.get_room(&room_id).context("room not found - has the bot joined it?")?;
+    let content = RoomMessageEventContent::text_plain(&message);
+    room.send(content).await?;
+
+    eprintln!("sent to {room_id}");
+    Ok(())
+}