cassandra_example.php

// create a file under your app/components/Cassandra.php and put the following code in it.

<?php

namespace app\components;

use yii\base\Component;

/**
 * Cassandra component.
 */

class Cassandra extends Component
{
    protected $session = null;
    public $keyspace = null;
    public $servers = null;
    public $result = null;

    public function init()
    {
        $cluster = \Cassandra::cluster()->build();
        $this->session = $cluster->connect($this->keyspace);
    }

    public function query($cql)
    {
        $this->result = $this->session->execute($cql);

        return $this;
    }

    public function all()
    {
        return iterator_to_array($this->result, true);
    }
}
?>

// configure your newly created cassandra components in config/web.php
<?php

[
//...


'cassandra' => [
    'class' => 'app\components\Cassandra',
    'keyspace' => 'adstream',
    'servers' => ['127.0.0.1:9042'],
],

// ...
]


// once all that is in place you can query your cassandra tables anywhere in your app

$data = Yii::$app->cassandra->query('SELECT * FROM transactions')->all();

foreach($data as $row) {
    echo $row['user_agent'];
}