wikimedia/mediawiki-core

View on GitHub
includes/PHPVersionCheck.php

Summary

Maintainability
B
6 hrs
Test Coverage
<?php
/**
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 * http://www.gnu.org/copyleft/gpl.html
 *
 * @file
 */

// phpcs:disable Generic.Arrays.DisallowLongArraySyntax,PSR2.Classes.PropertyDeclaration,MediaWiki.Usage.DirUsage
// phpcs:disable Squiz.Scope.MemberVarScope.Missing,Squiz.Scope.MethodScope.Missing
/**
 * Check PHP Version, as well as for composer dependencies in entry points,
 * and display something vaguely comprehensible in the event of a totally
 * unrecoverable error.
 *
 * @note Since we can't rely on anything external, the minimum PHP versions
 * and MW current version are hardcoded in this class.
 *
 * @note This class uses setter methods instead of a constructor so that
 * it can be compatible with PHP 4 through PHP 8 (without warnings).
 */
class PHPVersionCheck {
    /** @var string The number of the MediaWiki version used. If you're updating MW_VERSION in Defines.php, you must also update this value. */
    var $mwVersion = '1.43';

    /** @var string[] A mapping of PHP functions to PHP extensions. */
    var $functionsExtensionsMapping = array(
        'mb_substr'   => 'mbstring',
        'xml_parser_create' => 'xml',
        'ctype_digit' => 'ctype',
        'json_decode' => 'json',
        'iconv'       => 'iconv',
        'mime_content_type' => 'fileinfo',
        'intl_is_failure' => 'intl',
    );

    /**
     * @var string The format used for errors. One of "text" or "html"
     */
    var $format = 'text';

    /**
     * @var string
     */
    var $scriptPath = '/';

    /**
     * Set the format used for errors.
     *
     * @param string $format One of "text" or "html"
     */
    function setFormat( $format ) {
        $this->format = $format;
    }

    /**
     * Set the script path used for images in HTML-formatted errors.
     *
     * @param string $scriptPath
     */
    function setScriptPath( $scriptPath ) {
        $this->scriptPath = $scriptPath;
    }

    /**
     * Displays an error, if the installed PHP version does not meet the minimum requirement.
     */
    function checkRequiredPHPVersion() {
        $minimumVersion = '7.4.3';

        /**
         * This is a list of known-bad ranges of PHP versions. Syntax is like SemVer – either:
         *
         *  - '1.2.3' to prohibit a single version of PHP, or
         *  - '1.2.3 – 1.2.5' to block a range, inclusive.
         *
         * Whitespace will be ignored.
         *
         * The key is not shown to users; use it to prompt future developers as to why this was
         * chosen, ideally one or more Phabricator task references.
         *
         * Remember to drop irrelevant ranges when bumping $minimumVersion.
         */
        $knownBad = array(
        );

        $passes = version_compare( PHP_VERSION, $minimumVersion, '>=' );

        $versionString = "PHP $minimumVersion or higher";

        // Left as a programmatic check to make it easier to update.
        if ( count( $knownBad ) ) {
            $versionString .= ' (and not ' . implode( ', ', array_values( $knownBad ) ) . ')';

            foreach ( $knownBad as $range ) {
                // As we don't have composer at this point, we have to do our own version range checking.
                if ( strpos( $range, '-' ) ) {
                    $passes = $passes && !(
                        version_compare( PHP_VERSION, trim( strstr( $range, '-', true ) ), '>=' )
                        && version_compare( PHP_VERSION, trim( substr( strstr( $range, '-', false ), 1 ) ), '<' )
                    );
                } else {
                    $passes = $passes && version_compare( PHP_VERSION, trim( $range ), '<>' );
                }
            }
        }

        if ( !$passes ) {
            $cliText = "Error: You are using an unsupported PHP version (PHP " . PHP_VERSION . ").\n"
            . "MediaWiki $this->mwVersion needs $versionString.\n\nCheck if you might have a newer "
            . "PHP executable with a different name.\n\n";

            $web = array();
            $web['intro'] = "MediaWiki $this->mwVersion requires $versionString; you are using PHP "
                . PHP_VERSION . ".";

            $web['longTitle'] = "Supported PHP versions";
            // phpcs:disable Generic.Files.LineLength
            $web['longHtml'] = <<<HTML
        <p>
            Please consider <a href="https://www.php.net/downloads.php">upgrading your copy of PHP</a>.
            PHP versions less than v8.1.0 are no longer <a href="https://www.php.net/supported-versions.php">supported</a>
            by the PHP Group and will not receive security or bugfix updates.
        </p>
        <p>
            If for some reason you are unable to upgrade your PHP version, you will need to
            <a href="https://www.mediawiki.org/wiki/Download">download</a> an older version of
            MediaWiki from our website. See our
            <a href="https://www.mediawiki.org/wiki/Compatibility#PHP">compatibility page</a>
            for details of which versions are compatible with prior versions of PHP.
        </p>
HTML;
            // phpcs:enable Generic.Files.LineLength
            $this->triggerError(
                $web,
                $cliText
            );
        }
    }

    /**
     * Displays an error, if the vendor/autoload.php file could not be found.
     */
    function checkVendorExistence() {
        if ( !file_exists( dirname( __FILE__ ) . '/../vendor/autoload.php' ) ) {
            $cliText = "Error: You are missing some external dependencies. \n"
                . "MediaWiki has external dependencies that need to be installed via Composer\n"
                . "or from a separate repository. Please see\n"
                . "https://www.mediawiki.org/wiki/Manual:Installation_requirements#PHP and\n"
                . "https://www.mediawiki.org/wiki/Download_from_Git#Fetch_external_libraries\n"
                . "for help on installing the required components.";

            $web = array();
            $web['intro'] = "Installing some external dependencies (e.g. via composer) is required.";
            $web['longTitle'] = 'External dependencies';
            // phpcs:disable Generic.Files.LineLength
            $web['longHtml'] = <<<HTML
        <p>
        MediaWiki has external dependencies that need to be installed via Composer
        or from a separate repository. Please see the
        <a href="https://www.mediawiki.org/wiki/Manual:Installation_requirements#PHP">PHP
        installation requirements</a> and the
        <a href="https://www.mediawiki.org/wiki/Download_from_Git#Fetch_external_libraries">instructions
        for installing PHP libraries</a> on mediawiki.org for help on installing the required components.
        </p>
HTML;
            // phpcs:enable Generic.Files.LineLength

            $this->triggerError( $web, $cliText );
        }
    }

    /**
     * Displays an error, if a PHP extension does not exist.
     */
    function checkExtensionExistence() {
        $missingExtensions = array();
        foreach ( $this->functionsExtensionsMapping as $function => $extension ) {
            if ( !function_exists( $function ) ) {
                $missingExtensions[] = $extension;
            }
        }

        if ( $missingExtensions ) {
            $missingExtText = '';
            $missingExtHtml = '';
            $baseUrl = 'https://www.php.net';
            foreach ( $missingExtensions as $ext ) {
                $missingExtText .= " * $ext <$baseUrl/$ext>\n";
                $missingExtHtml .= "<li><b>$ext</b> "
                    . "(<a href=\"$baseUrl/$ext\">more information</a>)</li>";
            }

            $cliText = "Error: Missing one or more required components of PHP.\n"
                . "You are missing a required extension to PHP that MediaWiki needs.\n"
                . "Please install:\n" . $missingExtText;

            $web = array();
            $web['intro'] = "Installing some PHP extensions is required.";
            $web['longTitle'] = 'Required components';
            $web['longHtml'] = <<<HTML
        <p>
        You are missing a required extension to PHP that MediaWiki
        requires to run. Please install:
        </p>
        <ul>
        $missingExtHtml
        </ul>
HTML;

            $this->triggerError( $web, $cliText );
        }
    }

    /**
     * Output headers that prevents error pages to be cached.
     */
    function outputHTMLHeader() {
        $protocol = isset( $_SERVER['SERVER_PROTOCOL'] ) ? $_SERVER['SERVER_PROTOCOL'] : 'HTTP/1.0';

        header( "$protocol 500 MediaWiki configuration Error" );
        // Don't cache error pages! They cause no end of trouble...
        header( 'Cache-Control: no-cache' );
    }

    /**
     * Returns an error page, which is suitable for output to the end user via a web browser.
     *
     * @param string $introText
     * @param string $longTitle
     * @param string $longHtml
     * @return string
     */
    function getIndexErrorOutput( $introText, $longTitle, $longHtml ) {
        $encLogo =
            htmlspecialchars( str_replace( '//', '/', $this->scriptPath . '/' ) .
                'resources/assets/mediawiki.png' );

        $introHtml = htmlspecialchars( $introText );
        $longTitleHtml = htmlspecialchars( $longTitle );

        header( 'Content-type: text/html; charset=UTF-8' );

        $finalOutput = <<<HTML
<!DOCTYPE html>
<html lang="en" dir="ltr">
    <head>
        <meta charset="UTF-8" />
        <title>MediaWiki {$this->mwVersion}</title>
        <style media="screen">
            body {
                color: #000;
                background-color: #fff;
                font-family: sans-serif;
                padding: 2em;
                text-align: center;
            }
            p, img, h1, h2, ul {
                text-align: left;
                margin: 0.5em 0 1em;
            }
            h1 {
                font-size: 120%;
            }
            h2 {
                font-size: 110%;
            }
        </style>
    </head>
    <body>
        <img src="{$encLogo}" alt="The MediaWiki logo" />
        <h1>MediaWiki {$this->mwVersion} internal error</h1>
        <p>
            {$introHtml}
        </p>
        <h2>{$longTitleHtml}</h2>
        {$longHtml}
    </body>
</html>
HTML;

        return $finalOutput;
    }

    /**
     * Display something vaguely comprehensible in the event of a totally unrecoverable error.
     * Does not assume access to *anything*; no globals, no autoloader, no database, no localisation.
     * Safe for PHP4 (and putting this here means that WebStart.php and GlobalSettings.php
     * no longer need to be).
     *
     * This function immediately terminates the PHP process.
     *
     * @param string[] $web
     *  - (string) intro: Short error message, displayed on top.
     *  - (string) longTitle: Title for the longer message.
     *  - (string) longHtml: The longer message, as raw HTML.
     * @param string $cliText
     */
    function triggerError( $web, $cliText ) {
        if ( $this->format === 'html' ) {
            // Used by index.php and mw-config/index.php
            $this->outputHTMLHeader();
            $finalOutput = $this->getIndexErrorOutput(
                $web['intro'],
                $web['longTitle'],
                $web['longHtml']
            );
        } else {
            // Used by Maintenance.php (CLI)
            $finalOutput = $cliText;
        }

        echo "$finalOutput\n";
        die( 1 );
    }
}

/**
 * Check PHP version and that external dependencies are installed, and
 * display an informative error if either condition is not satisfied.
 *
 * @param string $format One of "text" or "html"
 * @param string $scriptPath Used when an error is formatted as HTML.
 */
function wfEntryPointCheck( $format = 'text', $scriptPath = '/' ) {
    $phpVersionCheck = new PHPVersionCheck();
    $phpVersionCheck->setFormat( $format );
    $phpVersionCheck->setScriptPath( $scriptPath );
    $phpVersionCheck->checkRequiredPHPVersion();
    $phpVersionCheck->checkVendorExistence();
    $phpVersionCheck->checkExtensionExistence();
}