dashboard: a subscribed node's message written out, read from it when shown

A subscribed node's messages come without being written out (their stream leaves the
text out: up to 8 KiB each, 500 at a time), so the figures box said only when, both
ends, type and size of one. Now the node answers for one message by its number,
`GET /admin/dashboard/messages/own/{seq}` (`{"text": …}`, `404` once it isn't kept),
which pages of other origins may call as they do its streams (`cors::open`), and the
page reads it when the message is shown, with its narrow token, and keeps it on the
message. Where it can't be read, the box says why.

1 files changed, 15 insertions, 0 deletions

diff --git a/src/api/dashboard/mod.rs b/src/api/dashboard/mod.rs
index 7a643d0..3a50ca6 100644
--- a/src/api/dashboard/mod.rs
+++ b/src/api/dashboard/mod.rs
@@ -509,6 +509,7 @@ pub(crate) fn router(state: AppState) -> Router<AppState> {
             "/admin/dashboard/messages/own/events",
             get(own_messages_events),
         )
+        .route("/admin/dashboard/messages/own/{seq}", get(own_message))
         .layer(Extension(Hub::new(state, closing)))
 }
 
@@ -573,6 +574,20 @@ impl Drop for Watching {
     }
 }
 
+/// `GET /admin/dashboard/messages/own/{seq}`: the message `seq` of this node's
+/// (`messages/own/events`, which leaves it out) written out, `{"text": …}`, for a page
+/// subscribed to this node showing it; `404` once it isn't kept any more (the latest
+/// 1000, while someone looks).
+async fn own_message(
+    Extension(hub): Extension<Arc<Hub>>,
+    axum::extract::Path(seq): axum::extract::Path<u64>,
+) -> axum::response::Response {
+    match hub.state.traffic.log.text_of(seq) {
+        Some(text) => axum::Json(json!({ "text": text })).into_response(),
+        None => super::error_response(axum::http::StatusCode::NOT_FOUND, "not kept any more", None),
+    }
+}
+
 /// `GET /admin/dashboard/messages/own/events`: server-sent events, `messages` with the
 /// messages this node sent and received since the last, as they come (gathered for
 /// `MESSAGES_GATHERED` after the first), as the page's own `messages` events have them,