Mesh chat store: append-replicated log over the existing SSH trust

2026-08-17 16:41:25 -04:00
parent fbf6a07da9
commit 772a3bdce2
4 changed files with 402 additions and 0 deletions
@@ -74,3 +74,7 @@ php "$SCRIPT_DIR/api_cache_writer.php"
 # Failure is ignored on purpose: a missed sample costs resolution in one window, and this job's
 # actual purpose is the WebGUI cache.
 php "$SCRIPT_DIR/mesh_traffic_sample.php" >/dev/null 2>&1 || true
+
+# Retry any mesh chat that could not be delivered when it was sent — a partner being asleep is
+# the normal case for the message "my server is going down".
+php "$SCRIPT_DIR/node_chat_receive.php" --flush >/dev/null 2>&1 || true
@@ -0,0 +1,69 @@
+<?php
+// ═══════════════════════════════════════════════════════════════════════════════════════════════
+// PURPOSE
+//   Accept one mesh message from a partner and store it. Invoked over SSH by the sending node's
+//   vv_nc_deliver(), with the record on stdin.
+//
+// OPERATIONAL MODEL
+//   php node_chat_receive.php --channel=<id>          record on stdin, one JSON object
+//   php node_chat_receive.php --flush                 retry this host's own undelivered spool
+//
+//   Exit 0 means stored. The sender treats anything else as undelivered and spools for retry, so
+//   a non-zero exit here is a message that will arrive later rather than one that is lost.
+//
+// OPERATIONAL SAFEGUARDS
+//   Reached only over SSH with a key this mesh installed, so the caller already has root. This
+//   file therefore validates shape, not authority — there is no privilege here to protect that
+//   the transport has not already granted.
+//
+//   The channel is resolved against this host's own membership. A name that is not a channel
+//   this machine belongs to is refused, so the argument cannot address a path outside the store.
+//
+//   Storage is append-and-trim through vv_nc_append(), which is idempotent on message id — a
+//   retry of something that already landed is a no-op rather than a duplicate.
+//
+// DEPENDS ON
+//   include/node_chat.php   vv_nc_append(), vv_nc_channel(), vv_nc_flush_spool()
+// ═══════════════════════════════════════════════════════════════════════════════════════════════
+require_once dirname(__DIR__) . '/include/node_chat.php';
+
+$args = $argv ?? [];
+
+if (in_array('--flush', $args, true)) {
+    $n = vv_nc_flush_spool();
+    if ($n) echo "delivered $n queued message(s)\n";
+    exit(0);
+}
+
+$channel = '';
+foreach ($args as $a) {
+    if (str_starts_with($a, '--channel=')) $channel = substr($a, 10);
+}
+if ($channel === '' || !vv_nc_channel($channel)) {
+    fwrite(STDERR, "unknown channel\n");
+    exit(2);
+}
+
+$raw = stream_get_contents(STDIN);
+$msg = json_decode((string)$raw, true);
+if (!is_array($msg) || empty($msg['id']) || !isset($msg['text'])) {
+    fwrite(STDERR, "malformed message\n");
+    exit(2);
+}
+
+// Rebuilt rather than stored as sent: a record is only ever the fields this store understands,
+// so a sender running newer code cannot write keys this one will later hand to a page.
+$clean = [
+    'id'    => preg_replace('/[^a-f0-9]/i', '', (string)$msg['id']),
+    'ts'    => (int)($msg['ts'] ?? time()),
+    'from'  => preg_replace('/[^a-z0-9]/i', '', strtolower((string)($msg['from'] ?? ''))),
+    'kind'  => in_array($msg['kind'] ?? 'msg', ['msg', 'question', 'notice'], true) ? $msg['kind'] : 'msg',
+    'text'  => mb_substr((string)$msg['text'], 0, 4000),
+    'style' => [
+        'color' => preg_match('/^#[0-9a-f]{6}$/i', $msg['style']['color'] ?? '') ? $msg['style']['color'] : '',
+        'font'  => in_array($msg['style']['font'] ?? '', ['mono','sans','serif'], true) ? $msg['style']['font'] : '',
+    ],
+];
+if ($clean['id'] === '' || $clean['from'] === '') { fwrite(STDERR, "malformed message\n"); exit(2); }
+
+exit(vv_nc_append($channel, $clean) ? 0 : 1);