open-graph-scraper/lib/fallback.js

Node.js scraper module for Open Graph and Twitter Card info

const { findImageTypeFromUrl, isImageTypeValid } = require('./utils');

const doesElementExist = (selector, attribute, $) => (
  $(selector).attr(attribute) && $(selector).attr(attribute).length > 0
);

const fallback = (ogObject, options, $) => {
  // title fallback
  if (!ogObject.ogTitle) {
    if ($('title').text() && $('title').text().length > 0) {
      ogObject.ogTitle = $('title').text();
    } else if ($('head > meta[name="title"]').attr('content') && $('head > meta[name="title"]').attr('content').length > 0) {
      ogObject.ogTitle = $('head > meta[name="title"]').attr('content');
    } else if ($('.post-title').text() && $('.post-title').text().length > 0) {
      ogObject.ogTitle = $('.post-title').text();
    } else if ($('.entry-title').text() && $('.entry-title').text().length > 0) {
      ogObject.ogTitle = $('.entry-title').text();
    } else if ($('h1[class*="title" i] a').text() && $('h1[class*="title" i] a').text().length > 0) {
      ogObject.ogTitle = $('h1[class*="title" i] a').text();
    } else if ($('h1[class*="title" i]').text() && $('h1[class*="title" i]').text().length > 0) {
      ogObject.ogTitle = $('h1[class*="title" i]').text();
    }
  }

  // Get meta description tag if og description was not provided
  if (!ogObject.ogDescription) {
    if (doesElementExist('head > meta[name="description"]', 'content', $)) {
      ogObject.ogDescription = $('head > meta[name="description"]').attr('content');
    } else if (doesElementExist('head > meta[itemprop="description"]', 'content', $)) {
      ogObject.ogDescription = $('head > meta[itemprop="description"]').attr('content');
    } else if ($('#description').text() && $('#description').text().length > 0) {
      ogObject.ogDescription = $('#description').text();
    }
  }

  // Get all of images if there is no og:image info
  if (!ogObject.ogImage && options.ogImageFallback) {
    ogObject.ogImage = [];
    $('img').map((index, imageElement) => {
      if (doesElementExist(imageElement, 'src', $)) {
        const type = findImageTypeFromUrl($(imageElement).attr('src'));
        if (!isImageTypeValid(type)) return false;
        ogObject.ogImage.push({
          url: $(imageElement).attr('src'),
          width: $(imageElement).attr('width') || null,
          height: $(imageElement).attr('height') || null,
          type,
        });
      }
      return false;
    });
    if (ogObject.ogImage.length === 0) delete ogObject.ogImage;
  } else if (ogObject.ogImage && ogObject.ogImage.url && !ogObject.ogImage.type) {
    // if there isn't a type, try to pull it from the URL
    const type = findImageTypeFromUrl(ogObject.ogImage.url);
    if (isImageTypeValid(type)) ogObject.ogImage.type = type;
  }

  // audio fallback
  if (!ogObject.ogAudioURL && !ogObject.ogAudioSecureURL) {
    const audioElementValue = $('audio').attr('src');
    const audioSourceElementValue = $('audio > source').attr('src');
    if (doesElementExist('audio', 'src', $)) {
      if (audioElementValue.startsWith('https')) {
        ogObject.ogAudioSecureURL = audioElementValue;
      } else {
        ogObject.ogAudioURL = audioElementValue;
      }
      const audioElementTypeValue = $('audio').attr('type');
      if (!ogObject.ogAudioType && doesElementExist('audio', 'type', $)) ogObject.ogAudioType = audioElementTypeValue;
    } else if (doesElementExist('audio > source', 'src', $)) {
      if (audioSourceElementValue.startsWith('https')) {
        ogObject.ogAudioSecureURL = audioSourceElementValue;
      } else {
        ogObject.ogAudioURL = audioSourceElementValue;
      }
      const audioSourceElementTypeValue = $('audio > source').attr('type');
      if (!ogObject.ogAudioType && doesElementExist('audio > source', 'type', $)) ogObject.ogAudioType = audioSourceElementTypeValue;
    }
  }

  // locale fallback
  if (!ogObject.ogLocale) {
    if (doesElementExist('html', 'lang', $)) {
      ogObject.ogLocale = $('html').attr('lang');
    } else if (doesElementExist('head > meta[itemprop="inLanguage"]', 'content', $)) {
      ogObject.ogLocale = $('head > meta[itemprop="inLanguage"]').attr('content');
    }
  }

  // logo fallback
  if (!ogObject.ogLogo) {
    if (doesElementExist('meta[itemprop="logo"]', 'content', $)) {
      ogObject.ogLogo = $('meta[itemprop="logo"]').attr('content');
    } else if (doesElementExist('img[itemprop="logo"]', 'src', $)) {
      ogObject.ogLogo = $('img[itemprop="logo"]').attr('src');
    }
  }

  // url fallback
  if (!ogObject.ogUrl) {
    if (doesElementExist('link[rel="canonical"]', 'href', $)) {
      ogObject.ogUrl = $('link[rel="canonical"]').attr('href');
    } else if (doesElementExist('link[rel="alternate"][hreflang="x-default"]', 'href', $)) {
      ogObject.ogUrl = $('link[rel="alternate"][hreflang="x-default"]').attr('href');
    }
  }

  // date fallback
  if (!ogObject.ogDate) {
    if (doesElementExist('head > meta[name="date"]', 'content', $)) {
      ogObject.ogDate = $('head > meta[name="date"]').attr('content');
    } else if (doesElementExist('[itemprop*="datemodified" i]', 'content', $)) {
      ogObject.ogDate = $('[itemprop*="datemodified" i]').attr('content');
    } else if (doesElementExist('[itemprop="datepublished" i]', 'content', $)) {
      ogObject.ogDate = $('[itemprop="datepublished" i]').attr('content');
    } else if (doesElementExist('[itemprop*="date" i]', 'content', $)) {
      ogObject.ogDate = $('[itemprop*="date" i]').attr('content');
    } else if (doesElementExist('time[itemprop*="date" i]', 'datetime', $)) {
      ogObject.ogDate = $('time[itemprop*="date" i]').attr('datetime');
    } else if (doesElementExist('time[datetime]', 'datetime', $)) {
      ogObject.ogDate = $('time[datetime]').attr('datetime');
    }
  }

  return ogObject;
};

module.exports = fallback;