List feeds in the Directory before anyone subscribes, and clear out dead ones (#107)

The Directory showed a catalogue feed only once someone subscribed, and a feed left the
catalogue with its last subscriber, so nothing could be put there for others to find.

- A feed has a listed flag, set by ipx add --list (with --category for the Directory's chip).
  The web page keeps a listed feed in the catalogue when its last subscriber leaves.
- The Directory lists every catalogue feed; Popular still only what people subscribe to.
  popular() reads titles, artwork and categories through Db::feed_list, not three queries a
  feed. Subscribing from the Directory scans the feed at once.
- A feed nobody subscribes to is checked once a day at most.
- clean_directory, in the sweep before each scan, removes from the catalogue and the database
  a feed nobody subscribes to, with no file on disk and not from an OPML, that has failed for
  30 days or published nothing in a year. Run against production first: it removes nothing.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/web.rs

@@ -870,8 +870,13 @@ struct PopularRow {
 /// first. Popular is the top of it, the directory is all of it, and it is all that
 /// `subscribe_popular` will subscribe you to. An OPML or a Patreon creator is listed as the
 /// feeds inside it and never itself: both lists are for finding a show.
-async fn popular(state: &WebState, user_id: i64) -> Result<Vec<PopularRow>> {
+/// The catalogue as others may see it. `everything` is the Directory: every feed, with or
+/// without subscribers, so the ones an admin listed show before anyone takes them. Without it,
+/// Popular: only what people subscribe to.
+async fn popular(state: &WebState, user_id: i64, everything: bool) -> Result<Vec<PopularRow>> {
     let db = &state.ctx.db;
+    // One pass for every feed's title, artwork and category, not three queries a feed.
+    let mut listed = db.feed_list(user_id, None).await?;
     let mine: std::collections::HashSet<String> =
         db.subscriptions_for(user_id).await?.into_iter().map(|s| s.feed_id).collect();
     let counts = db.subscriber_counts().await?;
@@ -886,14 +891,14 @@ async fn popular(state: &WebState, user_id: i64) -> Result<Vec<PopularRow>> {
         let n = counts.get(&s.id).copied().unwrap_or(0);
         // A feed inside an OPML that looks private is as private as the OPML.
         let folder = s.cfg.group.as_deref().and_then(|g| by_id.get(g));
-        if n == 0
+        if (n == 0 && !everything)
             || is_folder.contains(s.id.as_str())
             || looks_private(&s.cfg)
             || folder.is_some_and(|f| looks_private(f))
         {
             continue;
         }
-        let sum = db.feed_summary(&s.id).await?;
+        let sum = listed.remove(&s.id).map(|l| l.summary).unwrap_or_default();
         let subscribed = mine.contains(&s.id);
         out.push(PopularRow {
             id: s.id.clone(),
@@ -914,7 +919,7 @@ async fn get_popular(
     State(state): State<WebState>,
     user: crate::db::User,
 ) -> Result<Json<Vec<PopularRow>>, ApiError> {
-    let mut rows = popular(&state, user.id).await?;
+    let mut rows = popular(&state, user.id, false).await?;
     rows.truncate(10);
     Ok(Json(rows))
 }
@@ -924,7 +929,7 @@ async fn get_directory(
     State(state): State<WebState>,
     user: crate::db::User,
 ) -> Result<Json<Vec<PopularRow>>, ApiError> {
-    let mut rows = popular(&state, user.id).await?;
+    let mut rows = popular(&state, user.id, true).await?;
     rows.sort_by_key(sort_name);
     Ok(Json(rows))
 }
@@ -940,10 +945,12 @@ async fn subscribe_popular(
     user: crate::db::User,
     Path(id): Path<String>,
 ) -> Result<Json<serde_json::Value>, ApiError> {
-    if !popular(&state, user.id).await?.iter().any(|p| p.id == id) {
+    if !popular(&state, user.id, true).await?.iter().any(|p| p.id == id) {
         return Err(ApiError::bad_request(format!("{id:?} is not in the directory")));
     }
     state.ctx.db.subscribe(user.id, &id).await?;
+    // A listed feed nobody took was checked once a day at most: read it now, not in an hour.
+    scan_soon(&state, Some(id.clone())).await;
     Ok(Json(serde_json::json!({ "id": id })))
 }
 
@@ -1073,6 +1080,7 @@ mod tests {
             password: None,
             password_env: None,
             category: None,
+            listed: false,
         };
         assert!(!looks_private(&f("https://feeds.twit.tv/twit.xml")));
         assert!(!looks_private(&f("https://example.com/rss?format=mp3")));
@@ -1119,7 +1127,7 @@ mod tests {
         crate::config::Feed {
             url: url.into(), folder: None, group: None, media_types: None, schedule: None, keywords: vec![], allow_explicit: false,
             auto_download: true, max_new_per_check: None, username: None,
-            password: None, password_env: None, category: None,
+            password: None, password_env: None, category: None, listed: false,
         }
     }
 
@@ -1505,8 +1513,12 @@ async fn remove_feed(
     }
 
     // Nobody is left: the feed stops being scanned. Its files and history stay, so if
-    // someone subscribes again they do not pull the back catalogue a second time.
+    // someone subscribes again they do not pull the back catalogue a second time. A feed an
+    // admin listed stays in the Directory, for the next person.
     let mut cfg = (*state.ctx.cfg()).clone();
+    if cfg.feeds.get(&id).is_some_and(|f| f.listed) {
+        return Ok(StatusCode::NO_CONTENT);
+    }
     if cfg.feeds.remove(&id).is_none() {
         // A derived feed: forget it here, though the OPML will list it again on the next
         // read unless you unsubscribe from the OPML itself.