Add option to toggle publishing for mailing list replies

For some lists, such as release announcement lists, you may not want
replies to posts published.

src/config.rs

@@ -65,6 +65,8 @@ pub struct GitlabWebhookConfig {
 #[derive(Clone, Deserialize)]
 pub struct MailListConfig {
     pub name: String,
+    #[serde(default = "default_true")]
+    pub publish_on_replies: bool,
     #[serde(default)]
     pub rooms: Vec<OwnedRoomOrAliasId>,
 }
@@ -89,6 +91,10 @@ pub struct Config {
     pub mail_archive: Option<MailArchiveConfig>,
 }
 
+fn default_true() -> bool {
+    true
+}
+
 fn load_blocking(path: &String) -> anyhow::Result<Config> {
     let f = File::open(path)?;
     let r = BufReader::new(f);

src/mail_archive.rs

@@ -105,6 +105,7 @@ async fn handle_list(
     http_client: &reqwest::Client,
     url: &String,
     matrix_client: &Client,
+    publish_on_replies: bool,
     room_ids: &[OwnedRoomOrAliasId],
 ) -> anyhow::Result<()> {
     let list_state = load_list_state(state_file).await?;
@@ -161,11 +162,15 @@ async fn handle_list(
 
     for room in rooms {
         for item in &items {
-            let msg =
-                RoomMessageEventContent::text_markdown(format!("\\[{}\\] [{}]({})", list.name, item.title, item.link));
+            if publish_on_replies || !item.title.starts_with("Re: ") {
+                let msg = RoomMessageEventContent::text_markdown(format!(
+                    "\\[{}\\] [{}]({})",
+                    list.name, item.title, item.link
+                ));
                 room.send(msg, None)
                     .await
                     .with_context(|| format!("Failed to send message to room '{}'", room.room_id()))?;
+            }
             save_list_state(
                 ListState {
                     last_pub_date: item.pub_date.value,
@@ -207,8 +212,16 @@ pub fn start_polling(config: MailArchiveConfig, matrix_client: Client) -> anyhow
             tokio::spawn(async move {
                 if !room_ids.is_empty() {
                     loop {
-                        if let Err(err) =
-                            handle_list(&list, &state_file, &http_client, &url, &matrix_client, &room_ids).await
+                        if let Err(err) = handle_list(
+                            &list,
+                            &state_file,
+                            &http_client,
+                            &url,
+                            &matrix_client,
+                            list.publish_on_replies,
+                            &room_ids,
+                        )
+                        .await
                         {
                             warn!("{:#}", err);
                         }