App\Http\Controllers\API\ChatController::postMessage PHP Method

    public function postMessage()
    {
        switch (Request::input('target_type')) {
            case 'channel':
                $target = Channel::findOrFail(Request::input('channel_id'));
                break;
            case 'user':
                $target = User::findOrFail(Request::input('user_id'));
                break;
            default:
                abort(422);
        }
        priv_check('ChatMessageSend', $target)->ensureCan();
        $target->sendMessage(Auth::user(), Request::input('message'));
        return json_encode('ok');
    }