PHP4系でもいけるSlack送信関数

// Slack送信関数
function sendSlackMessage($webhook_url, $message) {
    try {
        $data = array(
            'payload' => json_encode(array(
                'text' => $message
            ))
        );
        
        $ch = curl_init($webhook_url);
        
        curl_setopt($ch, CURLOPT_POST, 1);
        curl_setopt($ch, CURLOPT_POSTFIELDS, $data);
        curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
        curl_setopt($ch, CURLOPT_TIMEOUT, 30);
        
        $result = curl_exec($ch);
        
        if ($result === false) {
            throw new Exception("Slack通知の送信に失敗しました: " . curl_error($ch));
        }
        
        curl_close($ch);
        return true;
    } catch (Exception $e) {
        error_log("Slack通知エラー: " . $e->getMessage());
        return false;
    }
}