class.ilUtil.php

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<?php
 
use ILIAS\FileDelivery\Delivery;
use ILIAS\Filesystem\Stream\Streams;
use ILIAS\HTTP\Cookies\CookieFactoryImpl;
use ILIAS\HTTP\Cookies\Cookie;
 
class ilUtil
{
    public static function getImageTagByType(string $a_type, string $a_path, bool $a_big = false): string
    {
        global $DIC;
 
        $lng = $DIC->language();
 
        $size = ($a_big)
            ? "big"
            : "small";
 
        $filename = ilObject::_getIcon(0, $size, $a_type);
 
        return "<img src=\"" . $filename . "\" alt=\"" . $lng->txt("obj_" . $a_type) . "\" title=\"" . $lng->txt(
            "obj_" . $a_type
        ) . "\" border=\"0\" vspace=\"0\"/>";
    }
 
    public static function getImagePath(
        string $image_name,
        string $module_path = "", // this parameter only supports "" value
        string $mode = "output", // this parameter does not control anything anymore
        bool $offline = false
    ): string {
        if ($offline) {
            return "./images/" . $image_name;
        }
 
        global $DIC;
        $styleDefinition = $DIC["styleDefinition"] ?? null;
 
        if ($module_path != "") {
            throw new \LogicException(
                "\$module_path only supports '' as value."
            );
        }
 
        $use_custom_skin = (ilStyleDefinition::getCurrentSkin() !== "default");
 
        if ($use_custom_skin) {
            $filename =
                "./Customizing/skin/"
                . ilStyleDefinition::getCurrentSkin() . "/"
                . ilStyleDefinition::getCurrentStyle() . "/"
                . (!is_object($styleDefinition) ? "images" : $styleDefinition->getImageDirectory(ilStyleDefinition::getCurrentStyle())) . "/"
                . $image_name;
 
            if (file_exists($filename)) {
                return $filename;
            }
        }
 
        return "./assets/images/" . $image_name;
    }
 
    public static function getHtmlPath(string $relative_path): string
    {
        if (substr($relative_path, 0, 2) == './') {
            $relative_path = (substr($relative_path, 1));
        }
        if (substr($relative_path, 0, 1) != '/') {
            $relative_path = '/' . $relative_path;
        }
        $htmlpath = ILIAS_HTTP_PATH . $relative_path;
        return $htmlpath;
    }
 
    public static function getStyleSheetLocation(
        string $mode = "output",
        string $a_css_name = ""
    ): string {
        $force_reload = ($mode !== "filesystem");
        $use_default_style_file = ($a_css_name === "");
        $use_custom_skin = (ilStyleDefinition::getCurrentSkin() !== "default");
 
        // use ilStyleDefinition instead of account to get the current style
 
        if ($use_default_style_file) {
            $stylesheet_name = ilStyleDefinition::getCurrentStyle() . ".css";
        } else {
            $stylesheet_name = $a_css_name;
        }
 
        if ($use_custom_skin) {
            $filename =
                "./Customizing/skin/"
                . ilStyleDefinition::getCurrentSkin() . "/"
                . ilStyleDefinition::getCurrentStyle() . "/"
                . $stylesheet_name;
        } else {
            $filename = "./assets/css/" . $stylesheet_name;
        }
 
        if (!$force_reload) {
            return $filename;
        }
 
        // add version as parameter to force reload for new releases
 
        // use version from template xml to force reload on changes
        $skin = ilStyleDefinition::getSkins()[ilStyleDefinition::getCurrentSkin()];
        $skin_version = $skin->getVersion();
        if ($skin_version !== "") {
            $skin_version_appendix = str_replace(".", "-", $skin_version);
        } else {
            $skin_version_appendix = '0';
        }
 
        return $filename . "?skin_version=" . $skin_version_appendix;
    }
 
    public static function getNewContentStyleSheetLocation(string $mode = "output"): string
    {
 
        // use ilStyleDefinition instead of account to get the current skin and style
        if (ilStyleDefinition::getCurrentSkin() == "default") {
            $in_style = "./templates/" . ilStyleDefinition::getCurrentSkin() . "/"
                . ilStyleDefinition::getCurrentStyle() . "_cont.css";
        } else {
            $in_style = "./Customizing/skin/" . ilStyleDefinition::getCurrentSkin() . "/"
                . ilStyleDefinition::getCurrentStyle() . "_cont.css";
        }
 
        if (is_file("./" . $in_style)) {
            return $in_style;
        } else {
            return "assets/css/delos_cont.css";
        }
    }
 
    public static function switchColor(int $a_num, string $a_css1, string $a_css2): string
    {
        if (!($a_num % 2)) {
            return $a_css1;
        } else {
            return $a_css2;
        }
    }
 
    public static function makeClickable(
        string $a_text,
        bool $detectGotoLinks = false,
        ?string $ilias_http_path = null
    ): string {
        global $DIC;
 
        $ret = $DIC->refinery()->string()->makeClickable()->transform($a_text);
 
        if ($detectGotoLinks) {
            $ilias_http_path = $ilias_http_path ?? (defined('ILIAS_HTTP_PATH') ? ILIAS_HTTP_PATH : '');
 
            $goto = '<a[^>]*href="(' . str_replace('@', '\@', $ilias_http_path) . '/goto';
            $regExp = $goto . '.php\?target=\w+_(\d+)[^"]*)"[^>]*>[^<]*</a>';
            $ret = preg_replace_callback(
                '@' . $regExp . '@i',
                [self::class, 'replaceLinkProperties'],
                $ret
            );
 
            // Edited this regex to allow multiple links in $ret: .* to [^"><]*.
            $regExp = $goto . '_[^"><]*[a-z0-9]+_([0-9]+)\.html)"[^>]*>[^<]*</a>';
            $ret = preg_replace_callback(
                '@' . $regExp . '@i',
                [self::class, 'replaceLinkProperties'],
                $ret
            );
        }
 
        return $ret;
    }
 
    private static function replaceLinkProperties(array $matches): string
    {
        global $DIC;
        $cache = $DIC['ilObjDataCache'];
 
        $link = $matches[0];
        $ref_id = (int) $matches[2];
        if ($ref_id > 0) {
            $obj_id = $cache->lookupObjId($ref_id);
            if ($obj_id > 0) {
                $title = $cache->lookupTitle($obj_id);
                $link = '<a href="' . $matches[1] . '" target="_self">' . $title . '</a>';
            }
        }
 
        return $link;
    }
 
    public static function is_email(
        string $a_email,
        ?ilMailRfc822AddressParserFactory $mailAddressParserFactory = null
    ): bool {
        if ($mailAddressParserFactory === null) {
            $mailAddressParserFactory = new ilMailRfc822AddressParserFactory();
        }
 
        try {
            $parser = $mailAddressParserFactory->getParser($a_email);
            $addresses = $parser->parse();
            return count($addresses) == 1 && $addresses[0]->getHost() != ilMail::ILIAS_HOST;
        } catch (ilException $e) {
            return false;
        }
    }
 
    public static function isLogin(string $a_login): bool
    {
        if (empty($a_login)) {
            return false;
        }
 
        if (strlen($a_login) < 3) {
            return false;
        }
 
        // FIXME - If ILIAS is configured to use RFC 822
        //         compliant mail addresses we should not
        //         allow the @ character.
        if (!preg_match("/^[A-Za-z0-9_\.\+\*\@!\$\%\~\-]+$/", $a_login)) {
            return false;
        }
 
        return true;
    }
 
    public static function img(
        string $a_src,
        ?string $a_alt = null,
        $a_width = "",
        $a_height = "",
        $a_border = 0,
        $a_id = "",
        $a_class = ""
    ) {
        $img = '<img src="' . $a_src . '"';
        if (!is_null($a_alt)) {
            $img .= ' alt="' . htmlspecialchars($a_alt) . '"';
        }
        if ($a_width != "") {
            $img .= ' width="' . htmlspecialchars($a_width) . '"';
        }
        if ($a_height != "") {
            $img .= ' height="' . htmlspecialchars($a_height) . '"';
        }
        if ($a_class != "") {
            $img .= ' class="' . $a_class . '"';
        }
        if ($a_id != "") {
            $img .= ' id="' . $a_id . '"';
        }
        $img .= ' />';
 
        return $img;
    }
 
    public static function deliverData(
        string $a_data,
        string $a_filename,
        string $mime = "application/octet-stream"
    ): void {
        global $DIC;
        $delivery = new Delivery(
            Delivery::DIRECT_PHP_OUTPUT,
            $DIC->http()
        );
        $delivery->setMimeType($mime);
        $delivery->setSendMimeType(true);
        $delivery->setDisposition(Delivery::DISP_ATTACHMENT);
        $delivery->setDownloadFileName($a_filename);
        $delivery->setConvertFileNameToAsci(true);
        $repsonse = $DIC->http()->response()->withBody(Streams::ofString($a_data));
        $DIC->http()->saveResponse($repsonse);
        $delivery->deliver();
    }
 
    public static function appendUrlParameterString(string $a_url, string $a_par, bool $xml_style = false): string
    {
        $amp = $xml_style
            ? "&amp;"
            : "&";
 
        $url = (is_int(strpos($a_url, "?")))
            ? $a_url . $amp . $a_par
            : $a_url . "?" . $a_par;
 
        return $url;
    }
 
    public static function stripSlashes(string $a_str, bool $a_strip_html = true, string $a_allow = ""): string
    {
        if (ini_get("magic_quotes_gpc")) {
            $a_str = stripslashes($a_str);
        }
 
        return ilUtil::secureString($a_str, $a_strip_html, $a_allow);
    }
 
    public static function stripOnlySlashes(string $a_str): string
    {
        if (ini_get("magic_quotes_gpc")) {
            $a_str = stripslashes($a_str);
        }
 
        return $a_str;
    }
 
    public static function secureString(string $a_str, bool $a_strip_html = true, string $a_allow = ""): string
    {
        // check whether all allowed tags can be made secure
        $only_secure = true;
        $allow_tags = explode(">", $a_allow);
        $sec_tags = ilUtil::getSecureTags();
        $allow_array = [];
        foreach ($allow_tags as $allow) {
            if ($allow != "") {
                $allow = str_replace("<", "", $allow);
 
                if (!in_array($allow, $sec_tags)) {
                    $only_secure = false;
                }
                $allow_array[] = $allow;
            }
        }
 
        // default behaviour: allow only secure tags 1:1
        if (($only_secure || $a_allow == "") && $a_strip_html) {
            if ($a_allow === "") {
                $allow_array = ["b",
                                "i",
                                "strong",
                                "em",
                                "code",
                                "cite",
                                "gap",
                                "sub",
                                "sup",
                                "pre",
                                "strike",
                                "bdo"
                ];
            }
 
            // this currently removes parts of strings like "a <= b"
            // because "a <= b" is treated like "<spam onclick='hurt()'>ss</spam>"
            $a_str = ilUtil::maskSecureTags($a_str, $allow_array);
            $a_str = strip_tags($a_str);        // strip all other tags
            $a_str = ilUtil::unmaskSecureTags($a_str, $allow_array);
 
            // a possible solution could be something like:
            // $a_str = str_replace("<", "&lt;", $a_str);
            // $a_str = str_replace(">", "&gt;", $a_str);
            // $a_str = ilUtil::unmaskSecureTags($a_str, $allow_array);
            //
            // output would be ok then, but input fields would show
            // "a &lt;= b" for input "a <= b" if data is brought back to a form
        } else {
            // only for scripts, that need to allow more/other tags and parameters
            if ($a_strip_html) {
                $a_str = ilUtil::stripScriptHTML($a_str, $a_allow);
            }
        }
 
        return $a_str;
    }
 
    public static function getSecureTags(): array
    {
        return ["strong",
                "em",
                "u",
                "strike",
                "ol",
                "li",
                "ul",
                "p",
                "div",
                "i",
                "b",
                "code",
                "sup",
                "sub",
                "pre",
                "gap",
                "a",
                "img",
                "bdo"
        ];
    }
 
    private static function maskSecureTags(string $a_str, array $allow_array): string
    {
        foreach ($allow_array as $t) {
            switch ($t) {
                case "a":
                    $a_str = ilUtil::maskAttributeTag($a_str, "a", "href");
                    break;
 
                case "img":
                    $a_str = ilUtil::maskAttributeTag($a_str, "img", "src");
                    break;
 
                case "p":
                case "div":
                    $a_str = ilUtil::maskTag($a_str, $t, [
                        ["param" => "align", "value" => "left"],
                        ["param" => "align", "value" => "center"],
                        ["param" => "align", "value" => "justify"],
                        ["param" => "align", "value" => "right"]
                    ]);
                    break;
 
                default:
                    $a_str = ilUtil::maskTag($a_str, $t);
                    break;
            }
        }
 
        return $a_str;
    }
 
    private static function unmaskSecureTags(string $a_str, array $allow_array): string
    {
        foreach ($allow_array as $t) {
            switch ($t) {
                case "a":
                    $a_str = ilUtil::unmaskAttributeTag($a_str, "a", "href");
                    break;
 
                case "img":
                    $a_str = ilUtil::unmaskAttributeTag($a_str, "img", "src");
                    break;
 
                case "p":
                case "div":
                    $a_str = ilUtil::unmaskTag($a_str, $t, [
                        ["param" => "align", "value" => "left"],
                        ["param" => "align", "value" => "center"],
                        ["param" => "align", "value" => "justify"],
                        ["param" => "align", "value" => "right"]
                    ]);
                    break;
 
                default:
                    $a_str = ilUtil::unmaskTag($a_str, $t);
                    break;
            }
        }
 
        return $a_str;
    }
 
    public static function securePlainString(string $a_str): string
    {
        if (ini_get("magic_quotes_gpc")) {
            return stripslashes($a_str);
        } else {
            return $a_str;
        }
    }
 
    public static function htmlencodePlainString(
        string $a_str,
        bool $a_make_links_clickable,
        bool $a_detect_goto_links = false
    ): string {
        $encoded = "";
 
        if ($a_make_links_clickable) {
            // Find text sequences in the plain text string which match
            // the URI syntax rules, and pass them to ilUtil::makeClickable.
            // Encode all other text sequences in the plain text string using
            // htmlspecialchars and nl2br.
            // The following expressions matches URI's as specified in RFC 2396.
            //
            // The expression matches URI's, which start with some well known
            // schemes, like "http:", or with "www.". This must be followed
            // by at least one of the following RFC 2396 expressions:
            // - alphanum:           [a-zA-Z0-9]
            // - reserved:           [;\/?:|&=+$,]
            // - mark:               [\\-_.!~*\'()]
            // - escaped:            %[0-9a-fA-F]{2}
            // - fragment delimiter: #
            // - uric_no_slash:      [;?:@&=+$,]
            $matches = [];
            $numberOfMatches = preg_match_all(
                '/(?:(?:http|https|ftp|ftps|mailto):|www\.)(?:[a-zA-Z0-9]|[;\/?:|&=+$,]|[\\-_.!~*\'()]|%[0-9a-fA-F]{2}|#|[;?:@&=+$,])+/',
                $a_str,
                $matches,
                PREG_OFFSET_CAPTURE
            );
            $pos1 = 0;
            $encoded = "";
 
            foreach ($matches[0] as $match) {
                $matched_text = $match[0];
                $pos2 = $match[1];
 
                // encode plain text
                $encoded .= nl2br(htmlspecialchars(substr($a_str, $pos1, $pos2 - $pos1)));
 
                // encode URI
                $encoded .= ilUtil::makeClickable($matched_text, $a_detect_goto_links);
 
 
                $pos1 = $pos2 + strlen($matched_text);
            }
            if ($pos1 < strlen($a_str)) {
                $encoded .= nl2br(htmlspecialchars(substr($a_str, $pos1)));
            }
        } else {
            $encoded = nl2br(htmlspecialchars($a_str));
        }
        return $encoded;
    }
 
    private static function maskAttributeTag(string $a_str, string $tag, string $tag_att): string
    {
        global $DIC;
 
        $ilLog = $DIC["ilLog"];
 
        $ws = "[\s]*";
        $att = $ws . "[^>]*" . $ws;
 
        while (preg_match(
            '/<(' . $tag . $att . '(' . $tag_att . $ws . '="' . $ws . '(([$@!*()~;,_0-9A-z\/:=%.&#?+\-])*)")' . $att . ')>/i',
            $a_str,
            $found
        )) {
            $old_str = $a_str;
            $a_str = preg_replace(
                "/<" . preg_quote($found[1], "/") . ">/i",
                '&lt;' . $tag . ' ' . $tag_att . $tag_att . '="' . $found[3] . '"&gt;',
                $a_str
            );
            if ($old_str == $a_str) {
                $ilLog->write(
                    "ilUtil::maskA-" . htmlentities($old_str) . " == " .
                    htmlentities($a_str)
                );
                return $a_str;
            }
        }
        $a_str = str_ireplace(
            "</$tag>",
            "&lt;/$tag&gt;",
            $a_str
        );
        return $a_str;
    }
 
    private static function unmaskAttributeTag(string $a_str, string $tag, string $tag_att): string
    {
        global $DIC;
 
        $ilLog = $DIC["ilLog"];
 
        while (preg_match(
            '/&lt;(' . $tag . ' ' . $tag_att . $tag_att . '="(([$@!*()~;,_0-9A-z\/:=%.&#?+\-])*)")&gt;/i',
            $a_str,
            $found
        )) {
            $old_str = $a_str;
            $a_str = preg_replace(
                "/&lt;" . preg_quote($found[1], "/") . "&gt;/i",
                '<' . $tag . ' ' . $tag_att . '="' . ilUtil::secureLink($found[2]) . '">',
                $a_str
            );
            if ($old_str == $a_str) {
                $ilLog->write(
                    "ilUtil::unmaskA-" . htmlentities($old_str) . " == " .
                    htmlentities($a_str)
                );
                return $a_str;
            }
        }
        $a_str = str_replace('&lt;/' . $tag . '&gt;', '</' . $tag . '>', $a_str);
        return $a_str;
    }
 
    public static function maskTag(string $a_str, string $tag, array $fix_param = []): string
    {
        $a_str = str_replace(
            ["<$tag>", "<" . strtoupper($tag) . ">"],
            "&lt;" . $tag . "&gt;",
            $a_str
        );
        $a_str = str_replace(
            ["</$tag>", "</" . strtoupper($tag) . ">"],
            "&lt;/" . $tag . "&gt;",
            $a_str
        );
 
        foreach ($fix_param as $p) {
            $k = $p["param"];
            $v = $p["value"];
            $a_str = str_replace(
                "<$tag $k=\"$v\">",
                "&lt;" . "$tag $k=\"$v\"" . "&gt;",
                $a_str
            );
        }
 
        return $a_str;
    }
 
    private static function unmaskTag(string $a_str, string $tag, array $fix_param = []): string
    {
        $a_str = str_replace("&lt;" . $tag . "&gt;", "<" . $tag . ">", $a_str);
        $a_str = str_replace("&lt;/" . $tag . "&gt;", "</" . $tag . ">", $a_str);
 
        foreach ($fix_param as $p) {
            $k = $p["param"];
            $v = $p["value"];
            $a_str = str_replace(
                "&lt;$tag $k=\"$v\"&gt;",
                "<" . "$tag $k=\"$v\"" . ">",
                $a_str
            );
        }
        return $a_str;
    }
 
    public static function secureLink(string $a_str): string
    {
        $a_str = str_ireplace("javascript", "jvscrpt", $a_str);
        $a_str = str_ireplace(["%00",
                               "%0a",
                               "%0d",
                               "%1a",
                               "&#00;",
                               "&#x00;",
                               "&#0;",
                               "&#x0;",
                               "&#x0a;",
                               "&#x0d;",
                               "&#10;",
                               "&#13;"
        ], "-", $a_str);
        return $a_str;
    }
 
    public static function stripScriptHTML(string $a_str, string $a_allow = "", bool $a_rm_js = true): string
    {
        $negativestr = "a,abbr,acronym,address,applet,area,base,basefont," .
            "big,blockquote,body,br,button,caption,center,cite,code,col," .
            "colgroup,dd,del,dfn,dir,div,dl,dt,em,fieldset,font,form,frame," .
            "frameset,h1,h2,h3,h4,h5,h6,head,hr,html,i,iframe,img,input,ins,isindex,kbd," .
            "label,legend,li,link,map,menu,meta,noframes,noscript,object,ol," .
            "optgroup,option,p,param,q,s,samp,script,select,small,span," .
            "strike,strong,style,sub,sup,table,tbody,td,textarea,tfoot,th,thead," .
            "title,tr,tt,u,ul,var";
        $a_allow = strtolower($a_allow);
        $negatives = explode(",", $negativestr);
        $outer_old_str = "";
        while ($outer_old_str != $a_str) {
            $outer_old_str = $a_str;
            foreach ($negatives as $item) {
                $pos = strpos($a_allow, "<$item>");
 
                // remove complete tag, if not allowed
                if ($pos === false) {
                    $old_str = "";
                    while ($old_str != $a_str) {
                        $old_str = $a_str;
                        $a_str = preg_replace("/<\/?\s*$item(\/?)\s*>/i", "", $a_str);
                        $a_str = preg_replace("/<\/?\s*$item(\/?)\s+([^>]*)>/i", "", $a_str);
                    }
                }
            }
        }
 
        if ($a_rm_js) {
            // remove all attributes if an "on..." attribute is given
            $a_str = preg_replace("/<\s*\w*(\/?)(\s+[^>]*)?(\s+on[^>]*)>/i", "", $a_str);
 
            // remove all attributes if a "javascript" is within tag
            $a_str = preg_replace("/<\s*\w*(\/?)\s+[^>]*javascript[^>]*>/i", "", $a_str);
 
            // remove all attributes if an "expression" is within tag
            // (IE allows something like <b style='width:expression(alert(1))'>test</b>)
            $a_str = preg_replace("/<\s*\w*(\/?)\s+[^>]*expression[^>]*>/i", "", $a_str);
        }
 
        return $a_str;
    }
 
    public static function secureUrl(string $url): string
    {
        // check if url is valid (absolute or relative)
        if (filter_var($url, FILTER_VALIDATE_URL) === false &&
            filter_var("http://" . $url, FILTER_VALIDATE_URL) === false &&
            filter_var("http:" . $url, FILTER_VALIDATE_URL) === false &&
            filter_var("http://de.de" . $url, FILTER_VALIDATE_URL) === false &&
            filter_var("http://de.de/" . $url, FILTER_VALIDATE_URL) === false) {
            return "";
        }
        if (trim(strtolower(parse_url($url, PHP_URL_SCHEME) ?? '')) === "javascript") {
            return "";
        }
 
        return htmlspecialchars($url, ENT_QUOTES);
    }
 
    public static function extractParameterString(string $a_parstr): array
    {
        // parse parameters in array
        $par = [];
        $ok = true;
        while (($spos = strpos($a_parstr, "=")) && $ok) {
            // extract parameter
            $cpar = substr($a_parstr, 0, $spos);
            $a_parstr = substr($a_parstr, $spos, strlen($a_parstr) - $spos);
            while (substr($cpar, 0, 1) == "," || substr($cpar, 0, 1) == " " || substr($cpar, 0, 1) == chr(13) || substr(
                $cpar,
                0,
                1
            ) == chr(10)) {
                $cpar = substr($cpar, 1, strlen($cpar) - 1);
            }
            while (substr($cpar, strlen($cpar) - 1, 1) == " " || substr($cpar, strlen($cpar) - 1, 1) == chr(
                13
            ) || substr($cpar, strlen($cpar) - 1, 1) == chr(10)) {
                $cpar = substr($cpar, 0, strlen($cpar) - 1);
            }
 
            // parameter name should only
            $cpar_old = "";
            while ($cpar != $cpar_old) {
                $cpar_old = $cpar;
                $cpar = preg_replace("/[^a-zA-Z0-9_]/i", "", $cpar);
            }
 
            // extract value
            if ($cpar != "") {
                if ($spos = strpos($a_parstr, "\"")) {
                    $a_parstr = substr($a_parstr, $spos + 1, strlen($a_parstr) - $spos);
                    $spos = strpos($a_parstr, "\"");
                    if (is_int($spos)) {
                        $cval = substr($a_parstr, 0, $spos);
                        $par[$cpar] = $cval;
                        $a_parstr = substr($a_parstr, $spos + 1, strlen($a_parstr) - $spos - 1);
                    } else {
                        $ok = false;
                    }
                } else {
                    $ok = false;
                }
            }
        }
 
        return $ok ? $par : [];
    }
 
    public static function yn2tf(string $a_yn): bool
    {
        if (strtolower($a_yn) === "y") {
            return true;
        } else {
            return false;
        }
    }
 
    public static function tf2yn(bool $a_tf): string
    {
        if ($a_tf) {
            return "y";
        } else {
            return "n";
        }
    }
 
    public static function deducibleSize(string $a_mime): bool
    {
        if (($a_mime == "image/gif") || ($a_mime == "image/jpeg") ||
            ($a_mime == "image/png") || ($a_mime == "application/x-shockwave-flash") ||
            ($a_mime == "image/tiff") || ($a_mime == "image/x-ms-bmp") ||
            ($a_mime == "image/psd") || ($a_mime == "image/iff")) {
            return true;
        } else {
            return false;
        }
    }
 
    public static function redirect(string $a_script): void
    {
        global $DIC;
 
        if (!isset($DIC['ilCtrl']) || !$DIC['ilCtrl'] instanceof ilCtrl) {
            (new InitCtrlService())->init($DIC);
        }
        $DIC->ctrl()->redirectToURL($a_script);
    }
 
    public static function insertInstIntoID(string $a_value): string
    {
        if (substr($a_value, 0, 4) == "il__") {
            $a_value = "il_" . IL_INST_ID . "_" . substr($a_value, 4, strlen($a_value) - 4);
        }
 
        return $a_value;
    }
 
    public static function groupNameExists(string $a_group_name, ?int $a_id = null): bool
    {
        global $DIC;
 
        $ilDB = $DIC->database();
 
        $ilErr = null;
        if (isset($DIC["ilErr"])) {
            $ilErr = $DIC["ilErr"];
        }
 
        if (empty($a_group_name)) {
            $message = __METHOD__ . ": No groupname given!";
            $ilErr->raiseError($message, $ilErr->WARNING);
        }
 
        $clause = ($a_id !== null) ? " AND obj_id != " . $ilDB->quote($a_id) . " " : "";
 
        $q = "SELECT obj_id FROM object_data " .
            "WHERE title = " . $ilDB->quote($a_group_name, "text") . " " .
            "AND type = " . $ilDB->quote("grp", "text") .
            $clause;
 
        $r = $ilDB->query($q);
 
        return $r->numRows() > 0;
    }
 
    public static function isWindows(): bool
    {
        return (strtolower(substr(php_uname(), 0, 3)) === "win");
    }
 
    public static function now(): string
    {
        return date("Y-m-d H:i:s");
    }
 
    public static function _getObjectsByOperations(
        $a_obj_type,
        string $a_operation,
        int $a_usr_id = 0,
        int $limit = 0
    ): array {
        global $DIC;
 
        $ilDB = $DIC->database();
        $rbacreview = $DIC->rbac()->review();
        $ilAccess = $DIC->access();
        $ilUser = $DIC->user();
        $ilSetting = $DIC->settings();
        $tree = $DIC->repositoryTree();
 
        if (!is_array($a_obj_type)) {
            $where = "WHERE type = " . $ilDB->quote($a_obj_type, "text") . " ";
        } else {
            $where = "WHERE " . $ilDB->in("type", $a_obj_type, false, "text") . " ";
        }
 
        // limit number of results default is search result limit
        if (!$limit) {
            $limit = (int) $ilSetting->get('search_max_hits', "100");
        }
        if ($limit == -1) {
            $limit = 10000;
        }
 
        // default to logged in usr
        $a_usr_id = $a_usr_id ?: $ilUser->getId();
        $a_roles = $rbacreview->assignedRoles($a_usr_id);
 
        // Since no rbac_pa entries are available for the system role. This function returns !all! ref_ids in the case the user
        // is assigned to the system role
        if ($rbacreview->isAssigned($a_usr_id, SYSTEM_ROLE_ID)) {
            $query = "SELECT ref_id FROM object_reference obr LEFT JOIN object_data obd ON obr.obj_id = obd.obj_id " .
                "LEFT JOIN tree ON obr.ref_id = tree.child " .
                $where .
                "AND tree = 1";
 
            $res = $ilDB->query($query);
            $counter = 0;
            $ref_ids = [];
            while ($row = $ilDB->fetchObject($res)) {
                // Filter recovery folder
                if ($tree->isGrandChild(RECOVERY_FOLDER_ID, $row->ref_id)) {
                    continue;
                }
 
                if ($counter++ >= $limit) {
                    break;
                }
 
                $ref_ids[] = $row->ref_id;
            }
            return $ref_ids;
        } // End Administrators
 
        // Check ownership if it is not asked for edit_permission or a create permission
        if ($a_operation == 'edit_permissions' or strpos($a_operation, 'create') !== false) {
            $check_owner = ") ";
        } else {
            $check_owner = "OR owner = " . $ilDB->quote($a_usr_id, "integer") . ") ";
        }
 
        $ops_ids = ilRbacReview::_getOperationIdsByName([$a_operation]);
        $ops_id = $ops_ids[0];
 
        $and = "AND ((" . $ilDB->in("rol_id", $a_roles, false, "integer") . " ";
 
        $query = "SELECT DISTINCT(obr.ref_id),obr.obj_id,type FROM object_reference obr " .
            "JOIN object_data obd ON obd.obj_id = obr.obj_id " .
            "LEFT JOIN rbac_pa  ON obr.ref_id = rbac_pa.ref_id " .
            $where .
            $and .
            "AND (" . $ilDB->like("ops_id", "text", "%i:" . $ops_id . "%") . " " .
            "OR " . $ilDB->like("ops_id", "text", "%:\"" . $ops_id . "\";%") . ")) " .
            $check_owner;
 
        $res = $ilDB->query($query);
        $counter = 0;
        $ref_ids = [];
        while ($row = $res->fetchRow(ilDBConstants::FETCHMODE_OBJECT)) {
            if ($counter >= $limit) {
                break;
            }
 
            // Filter objects in recovery folder
            if ($tree->isGrandChild(RECOVERY_FOLDER_ID, $row->ref_id)) {
                continue;
            }
 
            // Check deleted, hierarchical access ...
            if ($ilAccess->checkAccessOfUser($a_usr_id, $a_operation, '', $row->ref_id, $row->type, $row->obj_id)) {
                $counter++;
                $ref_ids[] = $row->ref_id;
            }
        }
        return $ref_ids ?: [];
    }
 
    public static function isHTML(string $a_text): bool
    {
        if (strlen(strip_tags($a_text)) < strlen($a_text)) {
            return true;
        }
 
        return false;
    }
 
    public static function __extractRefId(string $role_title): ?int
    {
        $test_str = explode('_', $role_title);
        $prefix = $test_str[0] ?? '';
 
        if ($prefix === 'il') {
            $ref_id = $test_str[3] ?? null;
            return is_numeric($ref_id) ? (int) $ref_id : null;
        }
        return null;
    }
 
    public static function __extractId(string $ilias_id, int $inst_id): ?int
    {
        $test_str = explode('_', $ilias_id);
 
        $parsed_inst_id = (int) ($test_str[1] ?? 0);
        $prefix = $test_str[0] ?? '';
 
        if ($prefix === 'il' && $parsed_inst_id === $inst_id && count($test_str) === 4) {
            return is_numeric($test_str[3]) ? (int) $test_str[3] : null;
        }
        return null;
    }
 
    public static function _sortIds(array $a_ids, string $a_table, string $a_field, string $a_id_name): array
    {
        global $DIC;
 
        $ilDB = $DIC->database();
 
        if (!$a_ids) {
            return [];
        }
 
        // use database to sort user array
        $where = "WHERE " . $a_id_name . " IN (";
        $where .= implode(",", ilArrayUtil::quoteArray($a_ids));
        $where .= ") ";
 
        $query = "SELECT " . $a_id_name . " FROM " . $a_table . " " .
            $where .
            "ORDER BY " . $a_field;
 
        $res = $ilDB->query($query);
        $ids = [];
        while ($row = $res->fetchRow(ilDBConstants::FETCHMODE_OBJECT)) {
            $ids[] = $row->$a_id_name;
        }
        return $ids;
    }
 
    public static function getSystemMessageHTML(string $a_txt, string $a_type = "info")
    {
        global $DIC;
 
        $box_factory = $DIC->ui()->factory()->messageBox();
        switch ($a_type) {
            case 'info':
                $box = $box_factory->info($a_txt);
                break;
            case 'success':
                $box = $box_factory->success($a_txt);
                break;
            case 'question':
                $box = $box_factory->confirmation($a_txt);
                break;
            case 'failure':
                $box = $box_factory->failure($a_txt);
                break;
            default:
                throw new InvalidArgumentException();
        }
 
        return $DIC->ui()->renderer()->render($box);
    }
 
    public static function setCookie(
        string $a_cookie_name,
        string $a_cookie_value = '',
        bool $a_also_set_super_global = true,
        bool $a_set_cookie_invalid = false
    ): void {
        global $DIC;
 
        $http = $DIC->http();
        $cookie_jar = $http->cookieJar();
 
        $cookie_factory = new CookieFactoryImpl();
 
        $cookie_expire = null;
        if (defined('IL_COOKIE_EXPIRE') && is_numeric(IL_COOKIE_EXPIRE) && IL_COOKIE_EXPIRE > 0) {
            $cookie_expire = (int) IL_COOKIE_EXPIRE;
        }
 
        $expires = null;
        if ($a_set_cookie_invalid) {
            $expires = time() - 10;
        } elseif ($cookie_expire > 0) {
            $expires = time() + $cookie_expire;
        }
 
        $cookie = $cookie_factory->create($a_cookie_name, $a_cookie_value)
                                 ->withExpires($expires)
                                 ->withSecure(defined('IL_COOKIE_SECURE') ? IL_COOKIE_SECURE : false)
                                 ->withPath(defined('IL_COOKIE_PATH') ? IL_COOKIE_PATH : '')
                                 ->withDomain(defined('IL_COOKIE_DOMAIN') ? IL_COOKIE_DOMAIN : '')
                                 ->withHttpOnly(defined('IL_COOKIE_HTTPONLY') ? IL_COOKIE_HTTPONLY : false);
 
 
        if (
            defined('IL_COOKIE_SECURE') && IL_COOKIE_SECURE &&
            (!isset(session_get_cookie_params()['samesite']) || strtolower(session_get_cookie_params()['samesite']) !== 'strict')
        ) {
            $cookie = $cookie->withSamesite(Cookie::SAMESITE_LAX);
        }
        $jar = $cookie_jar->with($cookie);
        $response = $jar->renderIntoResponseHeader($http->response());
        $http->saveResponse($response);
    }
 
    public static function _getHttpPath(): string
    {
        global $DIC;
 
        $ilIliasIniFile = $DIC["ilIliasIniFile"];
 
        if ((isset($_SERVER['SHELL']) && $_SERVER['SHELL']) || PHP_SAPI === 'cli' ||
            // fallback for windows systems, useful in crons
            (class_exists("ilContext") && !ilContext::usesHTTP())) {
            return $ilIliasIniFile->readVariable('server', 'http_path');
        } else {
            return ILIAS_HTTP_PATH;
        }
    }
 
    public static function parseImportId(string $a_import_id): array
    {
        $exploded = explode('_', $a_import_id);
 
        $parsed['orig'] = $a_import_id;
        if ($exploded[0] == 'il') {
            $parsed['prefix'] = $exploded[0];
        }
        if (is_numeric($exploded[1])) {
            $parsed['inst_id'] = (int) $exploded[1];
        }
        $parsed['type'] = $exploded[2];
 
        if (is_numeric($exploded[3])) {
            $parsed['id'] = (int) $exploded[3];
        }
        return $parsed;
    }
 
    protected static function fmtFloat(
        float $a_float,
        int $a_decimals = 0,
        ?string $a_dec_point = null,
        ?string $a_thousands_sep = null,
        bool $a_suppress_dot_zero = false
    ): string {
        global $DIC;
 
        $lng = $DIC->language();
 
        if ($a_dec_point === null) {
            $a_dec_point = ".";
        }
        if ($a_dec_point === '-lang_sep_decimal-') {
            $a_dec_point = ".";
        }
 
        if ($a_thousands_sep === null) {
            $a_thousands_sep = $lng->txt('lang_sep_thousand');
        }
        if ($a_thousands_sep === '-lang_sep_thousand-') {
            $a_thousands_sep = ",";
        }
 
        $txt = number_format($a_float, $a_decimals, $a_dec_point, $a_thousands_sep);
 
        // remove trailing ".0"
        if (($a_suppress_dot_zero == 0 || $a_decimals == 0)
            && substr($txt, -2) == $a_dec_point . '0'
        ) {
            $txt = substr($txt, 0, strlen($txt) - 2);
        }
        if ($a_float == 0 and $txt == "") {
            $txt = "0";
        }
 
        return $txt;
    }
 
    public static function formatSize(int $size, string $a_mode = 'short', ?ilLanguage $a_lng = null): string
    {
        global $DIC;
 
        $lng = $DIC->language();
        if ($a_lng == null) {
            $a_lng = $lng;
        }
 
        $mag = 1024;
 
        if ($size >= $mag * $mag * $mag) {
            $scaled_size = $size / $mag / $mag / $mag;
            $scaled_unit = 'lang_size_gb';
        } else {
            if ($size >= $mag * $mag) {
                $scaled_size = $size / $mag / $mag;
                $scaled_unit = 'lang_size_mb';
            } else {
                if ($size >= $mag) {
                    $scaled_size = $size / $mag;
                    $scaled_unit = 'lang_size_kb';
                } else {
                    $scaled_size = $size;
                    $scaled_unit = 'lang_size_bytes';
                }
            }
        }
 
        $result = self::fmtFloat(
            $scaled_size,
            ($scaled_unit
                    == 'lang_size_bytes') ? 0 : 1,
            $a_lng->txt('lang_sep_decimal'),
            $a_lng->txt('lang_sep_thousand'),
            true
        )
            . ' ' . $a_lng->txt($scaled_unit);
        if ($a_mode == 'long' && $size > $mag) {
            $result .= ' (' . self::fmtFloat(
                $size,
                0,
                $a_lng->txt('lang_sep_decimal'),
                $a_lng->txt('lang_sep_thousand')
            ) . ' '
                . $a_lng->txt('lang_size_bytes') . ')';
        }
 
        return $result;
    }
}