79 lines
2.4 KiB
JavaScript
79 lines
2.4 KiB
JavaScript
/**
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* Open Graph：复用 <title> / meta[name=description]，补齐绝对 og:url / og:image。
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* 爬虫可读 head 内静态 meta；本脚本在浏览器中按当前域名校正。
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*/
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(function () {
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var PROD_ORIGIN = 'https://ideship.com';
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var OG_IMAGE_PATH = '/site/assets/img/og-cover.png';
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var OG_IMAGE_REL = 'assets/img/og-cover.png';
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function truncate(text, max) {
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var value = String(text || '')
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.replace(/\s+/g, ' ')
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.trim();
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if (value.length <= max) return value;
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return value.slice(0, max);
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}
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function ensureMeta(property, content) {
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if (!content) return;
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var node = document.querySelector('meta[property="' + property + '"]');
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if (!node) {
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node = document.createElement('meta');
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node.setAttribute('property', property);
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document.head.appendChild(node);
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}
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node.setAttribute('content', content);
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}
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function resolveOrigin() {
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if (location.protocol === 'http:' || location.protocol === 'https:') {
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return location.origin;
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}
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return PROD_ORIGIN;
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}
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function resolvePageUrl(origin) {
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if (location.protocol === 'file:') {
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return /9610\.html$/i.test(location.pathname || '')
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? PROD_ORIGIN + '/9610.html'
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: PROD_ORIGIN + '/';
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}
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var path = location.pathname || '/';
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if (/\/index\.html$/i.test(path)) {
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path = path.replace(/\/index\.html$/i, '/') || '/';
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}
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if (path === '/site' || path === '/site/' || path === '/site/index.html') {
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path = '/';
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}
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return origin + path + (location.search || '');
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}
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function resolveImageUrl(origin) {
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if (origin === PROD_ORIGIN || /(^|\.)ideship\.com$/i.test(location.hostname || '')) {
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return origin + OG_IMAGE_PATH;
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}
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try {
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return new URL(OG_IMAGE_REL, location.href).href;
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} catch (e) {
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return origin + '/assets/img/og-cover.png';
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}
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}
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function applyOpenGraph() {
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var title = truncate(document.title, 30);
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var descNode = document.querySelector('meta[name="description"]');
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var description = truncate(descNode && descNode.getAttribute('content'), 60);
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var origin = resolveOrigin();
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ensureMeta('og:title', title);
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if (description) ensureMeta('og:description', description);
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ensureMeta('og:image', resolveImageUrl(origin));
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ensureMeta('og:url', resolvePageUrl(origin));
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ensureMeta('og:type', 'website');
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}
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applyOpenGraph();
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window.IDEOpenGraph = { refresh: applyOpenGraph };
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})();
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