lazyload.php

<?php
 
namespace Bitrix\Landing\Assets\PreProcessing;
 
use \Bitrix\Landing\Block;
use \Bitrix\Landing\Node;
use \Bitrix\Landing\File;
use \Bitrix\Main\Web\DOM;
 
class Lazyload
{
    protected const MODULE_ID = 'landing';
    protected const IMG_PLACEHOLDER_SIZE_DEFAULT = 333;
    protected const BG_PLACEHOLDER_SIZE_DEFAULT = 10;
 
    protected $block;
    protected $content;
    protected $manifest;
    protected $dom;
    protected $skipDynamic = true;
 
    protected function __construct(Block $block)
    {
        $this->block = $block;
        $this->manifest = $block->getManifest();
        $this->content = $block->getContent();
    }
 
    public function setSkipDynamic(bool $flag = true): void
    {
        $this->skipDynamic = $flag;
    }
 
    protected function parse(): void
    {
        if (!$this->content || !$this->manifest['nodes'])
        {
            return;
        }
        // tmp skip dynamic
        if ($this->skipDynamic && !empty($this->block->getDynamicParams()))
        {
            return;
        }
 
        $changed = false;
        foreach ($this->manifest['nodes'] as $selector => $node)
        {
            if ($node['type'] === 'img')
            {
                $node = Node\Img::changeNodeType($node, $this->block);
            }
 
            if ($node['type'] === 'img' || $node['type'] === 'styleimg')
            {
                $domElements = Node\Style::getNodesBySelector($this->block, $selector);
 
                if ($node['type'] === 'img')
                {
                    foreach ($domElements as $domElement)
                    {
                        if ($domElement->getTagName() === 'IMG')
                        {
                            $this->parseImgTag($domElement, $selector);
                        }
                        else
                        {
                            $this->parseBg($domElement, $selector);
                        }
                        $changed = true;
                    }
                }
                elseif ($node['type'] === 'styleimg')
                {
                    foreach ($domElements as $domElement)
                    {
                        if ($domElement->getTagName() !== 'IMG')
                        {
                            $this->parseStyleImg($domElement, $selector);
                            $changed = true;
                        }
                    }
                }
            }
        }
 
        if ($changed)
        {
            $this->block->saveContent($this->block->getDom()->saveHTML());
            $this->block->save();
        }
    }
 
    protected function parseImgTag(DOM\Element $node, string $selector): void
    {
        $origSrc = $node->getAttribute('src');
        if (!$origSrc)
        {
            return;
        }
 
        // get sizes for placeholder
        if (
            ($fileId = $node->getAttribute('data-fileid'))
            && $fileId > 0
            && ($fileArray = File::getFileArray($fileId))
        )
        {
            $width = $fileArray['WIDTH'];
            $height = $fileArray['HEIGHT'];
        }
        else if ($manifestSize = $this->getPlaceholderSizeFromManifest($selector))
        {
            [$width, $height] = $manifestSize;
        }
        else
        {
            $width = $height = self::IMG_PLACEHOLDER_SIZE_DEFAULT;
        }
 
        $lazySrc = $this->createPlaceholderImage($width, $height);
 
        $node->setAttribute('data-lazy-img', 'Y');
        $node->setAttribute('data-src', $origSrc);
        $node->setAttribute('src', $lazySrc);
        $node->setAttribute('loading', 'lazy');    //for native
        if ($srcset = $node->getAttribute('srcset'))
        {
            $node->removeAttribute('srcset');
            $node->setAttribute('data-srcset', $srcset);
        }
    }
 
    protected function parseBg(DOM\Element $node, string $selector): void
    {
        $styles = DOM\StyleInliner::getStyle($node, false);
        if (!$styles['background-image'])
        {
            return;
        }
        $origBg = implode('|', $styles['background-image']);
 
        // get sizes for placeholder
        if (
            ($fileId = $node->getAttribute('data-fileid'))
            && $fileId > 0
            && ($fileArray = File::getFileArray($fileId))
        )
        {
            $width = $fileArray['WIDTH'];
            $height = $fileArray['HEIGHT'];
        }
        else if ($manifestSize = $this->getPlaceholderSizeFromManifest($selector))
        {
            [$width, $height] = $manifestSize;
        }
        else
        {
            $width = $height = self::BG_PLACEHOLDER_SIZE_DEFAULT;
        }
 
        $node->setAttribute('data-lazy-bg', 'Y');
        $node->setAttribute('data-bg', $origBg);
 
        $lazySrc = $this->createPlaceholderImage($width, $height);
        DOM\StyleInliner::setStyle($node, array_merge($styles, ['background-image' => ["url({$lazySrc})"]]));
        if ($origSrc = self::getSrcByBgStyle($origBg))
        {
            if (isset($origSrc['src']))
            {
                $node->setAttribute('data-src', $origSrc['src']);
            }
            if (isset($origSrc['src2x']))
            {
                $node->setAttribute('data-src2x', $origSrc['src2x']);
            }
        }
    }
 
    protected function parseStyleImg(DOM\Element $node, string $selector): void
    {
        if (
            ($fileId = $node->getAttribute('data-fileid'))
            && $fileId > 0
            && ($fileArray = File::getFileArray($fileId))
        )
        {
            $width = $fileArray['WIDTH'];
            $height = $fileArray['HEIGHT'];
 
            $node->setAttribute('data-lazy-styleimg', 'Y');
            $node->setAttribute('data-style', $node->getAttribute('style'));
 
            $lazySrc = $this->createPlaceholderImage($width, $height);
            $node->setAttribute('style', "background-image:url({$lazySrc});");
 
            // todo: after add src in saveNode - get it too
        }
    }
 
    protected function getPlaceholderSizeFromManifest(string $selector)
    {
        if (!empty($dimensions = $this->manifest['nodes'][$selector]['dimensions']))
        {
            foreach ($dimensions as $key => $value)
            {
                if (mb_stripos($key, 'width') !== false)
                {
                    $width = $value;
                }
                if (mb_stripos($key, 'height') !== false)
                {
                    $height = $value;
                }
            }
 
            if (isset($width, $height))
            {
                return [$width, $height];
            }
 
            if (isset($width) || isset($height))
            {
                $size = $width ?? $height;
 
                return [$size, $size];
            }
        }
 
        return false;
    }
 
    protected function createPlaceholderImage(int $width, int $height): string
    {
        return "data:image/svg+xml;base64,".base64_encode('<svg xmlns="http://www.w3.org/2000/svg" width="'.$width.'" height="'.$height.'"><rect id="backgroundrect" width="100%" height="100%" x="0" y="0" fill="#ddd" fill-opacity=".7" stroke="none"/></svg>');
        // return "https://cdn.bitrix24.site/placeholder/{$width}x{$height}.png";
    }
 
    protected static function getSrcByBgStyle($style)
    {
        if (preg_match_all(
            '/url\‍(\'*([^\']+)\'*\‍)\s*([\d]*x*)/is',
            $style,
            $matches
        ))
        {
            $result = [];
            for ($i = 0, $c = count($matches[1]); $i < $c; $i++)
            {
                if ($matches[2][$i] == '2x')
                {
                    $result['src2x'] = $matches[1][$i];
                }
                else
                {
                    $result['src'] = $matches[1][$i];
                }
            }
 
            if(!empty($result['src']))
            {
                return $result;
            }
        }
 
        return false;
    }
 
    public static function processing(Block $block): void
    {
        $lazyload = new self($block);
        $lazyload->parse();
    }
 
    public static function processingDynamic(Block $block): void
    {
        $lazyload = new self($block);
        $lazyload->setSkipDynamic(false);
        $lazyload->parse();
    }
}