# protocol_cli

A development tool for testing the protocol layer in isolation. Runs a server that decodes and prints all incoming control messages, or a client that connects and sends a sample STREAM_OPEN request.

---

## Build

From the repository root:

```sh
make cli
```

The binary is placed in `build/cli/`.

---

## Usage

### Server mode

```sh
./protocol_cli --server [port]
```

Default port: `8000`. Listens for connections and prints a decoded description of every received frame.

Example output on an incoming STREAM_OPEN:

```
CONTROL_REQUEST  request_id=1  STREAM_OPEN  stream_id=1  format=0x0001  pixel_format=0x0000  origin=0x0001
```

Recognised message types and commands:

| Type | Description |
|---|---|
| `VIDEO_FRAME` | stream_id + compressed payload |
| `STREAM_EVENT` | stream_id + event code (INTERRUPTED / RESUMED) |
| `CONTROL_REQUEST` | request_id + command (STREAM_OPEN, STREAM_CLOSE, ENUM_DEVICES, ENUM_CONTROLS, GET_CONTROL, SET_CONTROL, ENUM_MONITORS) |
| `CONTROL_RESPONSE` | request_id + status (OK, ERROR, UNKNOWN_CMD, INVALID_PARAMS, NOT_FOUND) |

### Client mode

```sh
./protocol_cli --client <host> <port>
```

Connects to the server and sends a single STREAM_OPEN request, then waits for the response.

Example:

```sh
./protocol_cli --client 127.0.0.1 8000
```

---

## Relationship to the Video Routing System

`protocol_cli` exercises the `protocol` module that all nodes use to encode and decode wire messages. Pairing the server with a running node lets you inspect raw control traffic; pairing the client with a running node lets you inject individual commands for debugging.

See also: [`transport_cli.md`](transport_cli.md) for raw frame-level testing without protocol parsing.