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, 10 insertions, 0 deletions

diff --git a/src/transport/traffic.rs b/src/transport/traffic.rs
index bac0da7..5ff588e 100644
--- a/src/transport/traffic.rs
+++ b/src/transport/traffic.rs
@@ -325,6 +325,16 @@ impl MessageLog {
     }
 
     /// The messages after `seq`, the latest `most` of them.
+    /// The message `seq` written out, while it is kept.
+    pub(crate) fn text_of(&self, seq: u64) -> Option<String> {
+        let inner = self.inner.lock_or_recover();
+        inner
+            .entries
+            .iter()
+            .find(|entry| entry.seq == seq)
+            .map(|entry| entry.text.clone())
+    }
+
     pub(crate) fn after(&self, seq: u64, most: usize) -> Vec<Logged> {
         let inner = self.inner.lock_or_recover();
         let newer: Vec<&Logged> = inner.entries.iter().filter(|e| e.seq > seq).collect();