Initial commit

tcp-command-frame/client.mjs

@@ -0,0 +1,58 @@
+// client.mjs
+import net from 'node:net';
+
+const HOST = '192.168.2.25';   // <-- set Pico IP
+const PORT = 5505;
+
+function buildFrame(cmd, payload) {
+	const len = payload.length;
+	const frame = Buffer.alloc(3 + len);
+
+	frame[0] = cmd;
+	frame[1] = len & 0xff;        // len_lo
+	frame[2] = (len >> 8) & 0xff; // len_hi
+	payload.copy(frame, 3);
+
+	return frame;
+}
+
+function parseFrame(buffer) {
+	if (buffer.length < 3) {
+		return null;
+	}
+
+	const cmd = buffer[0];
+	const len = buffer[1] | (buffer[2] << 8);
+
+	if (buffer.length < 3 + len) {
+		return null;
+	}
+
+	const payload = buffer.subarray(3, 3 + len);
+	return { cmd, payload };
+}
+
+const socket = net.createConnection({ host: HOST, port: PORT });
+
+let rxBuffer = Buffer.alloc(0);
+
+socket.on('connect', () => {
+	const payload = Buffer.from('Test');
+	const frame = buildFrame(0x10, payload);
+	socket.write(frame);
+});
+
+socket.on('data', (chunk) => {
+	rxBuffer = Buffer.concat([rxBuffer, chunk]);
+
+	const frame = parseFrame(rxBuffer);
+	if (frame) {
+		console.log('CMD:', frame.cmd);
+		console.log('Payload:', frame.payload.toString());
+		socket.end();
+	}
+});
+
+socket.on('error', (err) => {
+	console.error(err);
+});