74 lines
2.6 KiB
JavaScript
74 lines
2.6 KiB
JavaScript
import { visit } from 'unist-util-visit';
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export function rehypeImageOptimization() {
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return (tree) => {
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// 1. 严谨写法：只遍历 element 类型的节点
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visit(tree, 'element', (node) => {
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// 2. 防御检查：必须是 img 标签，且必须有属性
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if (node.tagName !== 'img' || !node.properties) {
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return;
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}
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const src = node.properties.src;
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// 3. 防御检查：没有 src 属性直接跳过
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if (!src) return;
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let urlObj;
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try {
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// 4. 防御检查：尝试解析 URL，如果是相对路径会报错进入 catch
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urlObj = new URL(src);
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} catch (e) {
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// 解析失败（相对路径），只加懒加载，不处理链接
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node.properties.loading = 'lazy';
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node.properties.decoding = 'async';
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return;
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}
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// ============================================================
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// 业务逻辑：只处理 img.mckero.com
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// ============================================================
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if (urlObj.hostname !== 'img.mckero.com') {
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node.properties.loading = 'lazy';
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node.properties.decoding = 'async';
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return;
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}
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// ============================================================
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// 业务逻辑：跳过 WebP/AVIF
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// ============================================================
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const pathname = urlObj.pathname.toLowerCase();
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if (pathname.endsWith('.webp') || pathname.endsWith('.avif')) {
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node.properties.loading = 'lazy';
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node.properties.decoding = 'async';
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return;
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}
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// ============================================================
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// 业务逻辑：构造 Worker 链接
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// ============================================================
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const generateWorkerUrl = (originalSrc, width) => {
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const workerUrl = new URL('https://opt.mckero.com/');
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workerUrl.searchParams.set('url', originalSrc);
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if (width) {
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workerUrl.searchParams.set('width', width);
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}
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return workerUrl.toString();
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};
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// 修改 src (默认 800px)
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node.properties.src = generateWorkerUrl(src, 800);
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// 生成 srcset (500px 手机, 800px 电脑)
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const srcSmall = generateWorkerUrl(src, 500);
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const srcMedium = generateWorkerUrl(src, 800);
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node.properties.srcset = `${srcSmall} 500w, ${srcMedium} 800w`;
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// 补充标准属性
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node.properties.sizes = '(max-width: 600px) 500px, 800px';
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node.properties.loading = 'lazy';
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node.properties.decoding = 'async';
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});
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};
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} |