Preparation: Set the path to phantomjs and casperjs executables as Yii app params and then put the casperjs script(s) to run in a path specified by the alias root.casperjs. The casperjs script should be written to only output JSON.

CasperJS.php

<?php

class CasperJS
{

    static public function request($script, stdClass $params = null)
    {
        if (is_null($params)) {
            $params = new stdClass();
        }

        putenv("PHANTOMJS_EXECUTABLE=" . Yii::app()->params["phantomjs"]);
        chdir(Yii::getPathOfAlias("root.casperjs"));

        $jsonParams = json_encode($params);
        $cmd = Yii::app()->params["casperjs"] . " ./" . $script . " --params=" . escapeshellarg($jsonParams) . " 2>&1";

        $response = shell_exec($cmd);

        $parsed = json_decode($response);

        if ($parsed->status !== "ok")
            throw new Exception("CasperJS response without status ok. Raw response: $response");

        return $parsed;
    }

}