Keybase bot in PHP

keybase-bot.php

<?php

// launch with:
// $ keybase chat api-listen --filter-channels '[{"name":"channel_name", "topic_name": "channel_name", "members_type": "team"}]' | php -f keybase.php

define('KEYBASE_TEAM',        'team_name');
define('KEYBASE_CHANNEL',     'channel_name');

if(!defined('BOT_NAME')) {
	$keybase_status = `keybase status --json`;
	define('BOT_NAME', json_decode($keybase_status)->Username);
}

while(!feof(STDIN)){
	$line = fgets(STDIN);
	$data = json_decode($line);
	
	// print_r($data);	
	
	if(isset($data->msg->at_mention_usernames)) {
		
		// Detect bot mentions and respond
		if(in_array(BOT_NAME, $data->msg->at_mention_usernames)) {
			$message = $data->msg->content->text->body;
			$input = str_replace('@'.BOT_NAME.' ', '', $input);
			$response = 'I heard: '.$message;
			$command = 'keybase chat send --channel "'.KEYBASE_CHANNEL.'" '.KEYBASE_TEAM.' "'.$response.'"';
			$output = shell_exec($command);
		}
	}
}