class.ilMathJaxImage.php

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<?php

declare(strict_types=1);

use ILIAS\DI\Container;
use ILIAS\Filesystem\Visibility;
use ILIAS\Filesystem\Filesystem;

class ilMathJaxImage
{
    private const TYPE_PNG = 'png';
    private const TYPE_SVG = 'svg';

    protected Filesystem $fs;

    protected string $basepath = '/temp/tex';

    protected string $tex;

    protected string $suffix;

    protected string $salt;

    public function __construct(string $a_tex, string $a_type, int $a_dpi)
    {
        global $DIC;

        $this->fs = $DIC->filesystem()->web();
        $this->tex = $a_tex;

        switch ($a_type) {
            case self::TYPE_PNG:
                $this->suffix = '.png';
                break;
            case self::TYPE_SVG:
                $this->suffix = '.svg';
                break;
            default:
                throw new ilMathJaxException('imagetype not supported');
        }

        $this->salt = '#' . $a_dpi;
    }

    protected function filedir(): string
    {
        $hash = md5($this->tex . $this->salt);
        return $this->basepath
        . '/' . substr($hash, 0, 4)
        . '/' . substr($hash, 4, 4);
    }

    protected function filepath(): string
    {
        $hash = md5($this->tex . $this->salt);
        return $this->filedir() . '/' . $hash . $this->suffix;
    }

    public function absolutePath(): string
    {
        return CLIENT_WEB_DIR . $this->filepath();
    }

    public function exists(): bool
    {
        return $this->fs->has($this->filepath());
    }

    public function read(): string
    {
        return $this->fs->read($this->filepath());
    }

    public function write(string $a_content): void
    {
        // set the directory access of the whole relative file to visible
        // this is needed if TeX is used in certificates
        // the ILIAS java server must have read access to the files for the PDF generation
        // it may run with a different user account
        $dir = '';
        foreach (explode('/', $this->filedir()) as $part) {
            if (!empty($part)) {
                $dir = $dir . '/' . $part;
            }
            if (!$this->fs->hasDir($dir)) {
                $this->fs->createDir($dir, Visibility::PUBLIC_ACCESS);
            } else {
                $this->fs->setVisibility($dir, Visibility::PUBLIC_ACCESS);
            }
        }
        $this->fs->put($this->filepath(), $a_content);
    }

    public function getCacheSize(): string
    {
        $size = 0;
        if ($this->fs->hasDir($this->basepath)) {
            foreach ($this->fs->finder()->in([$this->basepath])->files() as $meta) {
                $size += $this->fs->getSize($meta->getPath(), 1)->inBytes();
            }
        }

        $type = array("K", "M", "G", "T", "P", "E", "Z", "Y");
        $size /= 1000;
        $counter = 0;
        while ($size >= 1000) {
            $size /= 1000;
            $counter++;
        }

        return (round($size, 1) . " " . $type[$counter] . "B");
    }

    public function clearCache(): void
    {
        $this->fs->deleteDir($this->basepath);
    }
}