86 lines
4.3 KiB
PHP
86 lines
4.3 KiB
PHP
<?php
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// ═══════════════════════════════════════════════════════════════════════════════════════════════
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// PURPOSE
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// Accept one mesh message from a partner and store it. Invoked over SSH by the sending node's
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// vv_nc_deliver(), with the record on stdin.
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//
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// OPERATIONAL MODEL
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// Exit 0 means stored. The sender treats anything else as undelivered and spools for retry, so
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// a non-zero exit here is a message that will arrive later rather than one that is lost.
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//
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// Two jobs in one file because they are two halves of the same contract: --channel takes what
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// a partner is delivering now, --flush pushes what this host failed to deliver earlier. A node
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// is both a receiver and a sender, and splitting them would mean two files that must agree on
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// the same spool layout.
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//
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// DESIGN PRINCIPLES
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// The exit code is the receipt, and it is the only one.
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// There is no acknowledgement message and no reply body. The sender is an SSH command that
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// already has an exit status, so inventing a second channel to say the same thing would
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// give the two ways to disagree.
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//
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// Refusing is cheaper than being wrong.
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// An unparseable record, an unknown channel or a failed write all exit non-zero and leave
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// the message in the sender's spool. A retry costs one SSH round trip; a message accepted
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// and dropped is gone with nothing recording that it existed.
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//
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// OPERATIONAL SAFEGUARDS
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// Reached only over SSH with a key this mesh installed, so the caller already has root. This
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// file therefore validates shape, not authority — there is no privilege here to protect that
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// the transport has not already granted.
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//
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// The channel is resolved against this host's own membership. A name that is not a channel
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// this machine belongs to is refused, so the argument cannot address a path outside the store.
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//
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// Storage is append-and-trim through vv_nc_append(), which is idempotent on message id — a
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// retry of something that already landed is a no-op rather than a duplicate.
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//
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// RUNTIME MODES
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// Not invoked by hand — the sending node's vv_nc_deliver() runs it over SSH.
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//
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// php node_chat_receive.php --channel=<id> store one JSON record, read from stdin
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// php node_chat_receive.php --flush retry this host's own undelivered spool
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//
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// DEPENDS ON
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// include/node_chat.php vv_nc_append(), vv_nc_channel(), vv_nc_flush_spool()
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// ═══════════════════════════════════════════════════════════════════════════════════════════════
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require_once dirname(__DIR__) . '/include/node_chat.php';
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$args = $argv ?? [];
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if (in_array('--flush', $args, true)) {
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$n = vv_nc_flush_spool();
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if ($n) echo "delivered $n queued message(s)\n";
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exit(0);
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}
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$channel = '';
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foreach ($args as $a) {
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if (str_starts_with($a, '--channel=')) $channel = substr($a, 10);
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}
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if ($channel === '' || !vv_nc_channel($channel)) {
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fwrite(STDERR, "unknown channel\n");
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exit(2);
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}
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$raw = stream_get_contents(STDIN);
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$msg = json_decode((string)$raw, true);
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if (!is_array($msg) || empty($msg['id']) || !isset($msg['text'])) {
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fwrite(STDERR, "malformed message\n");
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exit(2);
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}
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// Rebuilt rather than stored as sent: a record is only ever the fields this store understands,
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// so a sender running newer code cannot write keys this one will later hand to a page.
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$clean = [
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'id' => preg_replace('/[^a-f0-9]/i', '', (string)$msg['id']),
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'ts' => (int)($msg['ts'] ?? time()),
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'from' => preg_replace('/[^a-z0-9]/i', '', strtolower((string)($msg['from'] ?? ''))),
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'kind' => in_array($msg['kind'] ?? 'msg', ['msg', 'question', 'notice'], true) ? $msg['kind'] : 'msg',
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'text' => mb_substr((string)$msg['text'], 0, 4000),
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'style' => vv_nc_clean_style(is_array($msg['style'] ?? null) ? $msg['style'] : []),
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];
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if ($clean['id'] === '' || $clean['from'] === '') { fwrite(STDERR, "malformed message\n"); exit(2); }
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exit(vv_nc_append($channel, $clean) ? 0 : 1);
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