requirements.php

<?php
/**
 * Application requirement checker script.
 *
 * In order to run this script use the following console command:
 * php requirements.php
 *
 * In order to run this script from the web, you should copy it to the web root.
 * If you are using Linux you can create a hard link instead, using the following command:
 * ln requirements.php ../requirements.php
 */

// you may need to adjust this path to the correct Yii framework path
$frameworkPath = dirname(__FILE__) . '/vendor/yiisoft/yii2';

if (!is_dir($frameworkPath)) {
    echo '<h1>Error</h1>';
    echo '<p><strong>The path to yii framework seems to be incorrect.</strong></p>';
    echo '<p>You need to install Yii framework via composer or adjust the framework path in file <abbr title="' . __FILE__ . '">' . basename(__FILE__) . '</abbr>.</p>';
    echo '<p>Please refer to the <abbr title="' . dirname(__FILE__) . '/README.md">README</abbr> on how to install Yii.</p>';
    die();
}

require_once($frameworkPath . '/requirements/YiiRequirementChecker.php');
$requirementsChecker = new YiiRequirementChecker();

$gdMemo = $imagickMemo = 'Either GD PHP extension with FreeType support or ImageMagick PHP extension with PNG support is required for image CAPTCHA.';
$gdOK = $imagickOK = false;

if (extension_loaded('imagick')) {
    $imagick = new Imagick();
    $imagickFormats = $imagick->queryFormats('PNG');
    if (in_array('PNG', $imagickFormats)) {
        $imagickOK = true;
    } else {
        $imagickMemo = 'Imagick extension should be installed with PNG support in order to be used for image CAPTCHA.';
    }
}

if (extension_loaded('gd')) {
    $gdInfo = gd_info();
    if (!empty($gdInfo['FreeType Support'])) {
        $gdOK = true;
    } else {
        $gdMemo = 'GD extension should be installed with FreeType support in order to be used for image CAPTCHA.';
    }
}

/**
 * Adjust requirements according to application specifics.
 */
$requirements = array(
    // Database :
    array(
        'name' => 'PDO extension',
        'mandatory' => true,
        'condition' => extension_loaded('pdo'),
        'by' => 'All DB-related classes',
    ),
    array(
        'name' => 'PDO MySQL extension',
        'mandatory' => true,
        'condition' => extension_loaded('pdo_mysql'),
        'by' => 'All DB-related classes',
        'memo' => 'Required for MySQL database.',
    ),
    array(
        'name' => 'GD PHP extension with FreeType support',
        'mandatory' => true,
        'condition' => $gdOK,
        'by' => 'Image support',
        'memo' => $gdMemo,
    ),
    'phpExposePhp' => array(
        'name' => 'Expose PHP',
        'mandatory' => false,
        'condition' => $requirementsChecker->checkPhpIniOff("expose_php"),
        'by' => 'Security reasons',
        'memo' => '"expose_php" should be disabled at php.ini',
    ),
    'phpAllowUrlInclude' => array(
        'name' => 'PHP allow url include',
        'mandatory' => false,
        'condition' => $requirementsChecker->checkPhpIniOff("allow_url_include"),
        'by' => 'Security reasons',
        'memo' => '"allow_url_include" should be disabled at php.ini',
    ),
    'phpCmd' => array(
        'name' => 'PHP allow open a pipe to console processes',
        'mandatory' => true,
        'condition' => in_array('popen', get_defined_functions()['internal']) && in_array('pclose', get_defined_functions()['internal']),
        'by' => 'Console support',
        'memo' => '"disable_functions" should not contains popen and pclose functions at php.init',
    )
);

$requirementsChecker->checkYii()->check($requirements)->render();