feat(transport): introduce transport abstraction and socket-mode support for RustBridge

test/helpers/mock-socket-server.mjs

@@ -0,0 +1,124 @@
+#!/usr/bin/env node
+
+/**
+ * Mock "Rust daemon" for testing the SocketTransport and RustBridge socket mode.
+ * Creates a Unix socket server, accepts connections, and speaks the same
+ * JSON-over-newline IPC protocol as mock-rust-binary.mjs.
+ *
+ * Usage: node mock-socket-server.mjs <socket-path>
+ * Signals readiness by writing a JSON line to stdout: {"socketPath":"...","ready":true}
+ */
+
+import * as net from 'net';
+import * as fs from 'fs';
+
+const socketPath = process.argv[2];
+if (!socketPath) {
+  process.stderr.write('Usage: mock-socket-server.mjs <socket-path>\n');
+  process.exit(1);
+}
+
+// Remove stale socket file
+try { fs.unlinkSync(socketPath); } catch { /* ignore */ }
+
+/**
+ * Backpressure-aware write to a socket.
+ */
+function writeResponse(conn, data) {
+  const json = JSON.stringify(data) + '\n';
+  if (!conn.write(json)) {
+    conn.once('drain', () => {});
+  }
+}
+
+function handleLine(line, conn) {
+  let request;
+  try {
+    request = JSON.parse(line);
+  } catch {
+    return;
+  }
+
+  const { id, method, params } = request;
+
+  if (method === 'echo') {
+    writeResponse(conn, { id, success: true, result: params });
+  } else if (method === 'largeEcho') {
+    writeResponse(conn, { id, success: true, result: params });
+  } else if (method === 'error') {
+    writeResponse(conn, { id, success: false, error: 'Test error message' });
+  } else if (method === 'emitEvent') {
+    writeResponse(conn, { event: params.eventName, data: params.eventData });
+    writeResponse(conn, { id, success: true, result: null });
+  } else if (method === 'slow') {
+    setTimeout(() => {
+      writeResponse(conn, { id, success: true, result: { delayed: true } });
+    }, 100);
+  } else if (method === 'streamEcho') {
+    const count = params.count || 0;
+    let sent = 0;
+    const interval = setInterval(() => {
+      if (sent < count) {
+        writeResponse(conn, { id, stream: true, data: { index: sent, value: `chunk_${sent}` } });
+        sent++;
+      } else {
+        clearInterval(interval);
+        writeResponse(conn, { id, success: true, result: { totalChunks: count } });
+      }
+    }, 10);
+  } else if (method === 'streamError') {
+    writeResponse(conn, { id, stream: true, data: { index: 0, value: 'before_error' } });
+    setTimeout(() => {
+      writeResponse(conn, { id, success: false, error: 'Stream error after chunk' });
+    }, 20);
+  } else if (method === 'streamEmpty') {
+    writeResponse(conn, { id, success: true, result: { totalChunks: 0 } });
+  } else if (method === 'exit') {
+    writeResponse(conn, { id, success: true, result: null });
+    // In socket mode, 'exit' just closes this connection, not the server
+    setTimeout(() => conn.end(), 50);
+  } else {
+    writeResponse(conn, { id, success: false, error: `Unknown method: ${method}` });
+  }
+}
+
+const server = net.createServer((conn) => {
+  // Send ready event on each new connection
+  writeResponse(conn, { event: 'ready', data: { version: '1.0.0' } });
+
+  // Buffer-based newline scanner for incoming data
+  let buffer = Buffer.alloc(0);
+  conn.on('data', (chunk) => {
+    buffer = Buffer.concat([buffer, chunk]);
+    let idx;
+    while ((idx = buffer.indexOf(0x0A)) !== -1) {
+      const lineBuffer = buffer.subarray(0, idx);
+      buffer = buffer.subarray(idx + 1);
+      const line = lineBuffer.toString('utf8').trim();
+      if (line) {
+        handleLine(line, conn);
+      }
+    }
+  });
+
+  conn.on('error', () => { /* ignore client errors */ });
+});
+
+server.listen(socketPath, () => {
+  // Signal to parent that the server is ready
+  process.stdout.write(JSON.stringify({ socketPath, ready: true }) + '\n');
+});
+
+// Handle SIGTERM gracefully
+process.on('SIGTERM', () => {
+  server.close();
+  try { fs.unlinkSync(socketPath); } catch { /* ignore */ }
+  process.exit(0);
+});
+
+// Handle SIGINT
+process.on('SIGINT', () => {
+  server.close();
+  try { fs.unlinkSync(socketPath); } catch { /* ignore */ }
+  process.exit(0);
+});