blog/themes/typing/scripts/openGraph.js

'use strict'
/* global hexo */

/*
* Modified from the hexo version,
* https://github.com/hexojs/hexo/blob/master/lib/plugins/helper/open_graph.js
* for compatibility with cloudinary.js
* the <meta name="og:image"> now use
* data-src attribute of <img>, instead of src
*/

'use strict'

const moment = require('moment')
const { escapeHTML, htmlTag, stripHTML } = require('hexo-util')
let cheerio

function meta (name, content, escape) {
  if (escape !== false && typeof content === 'string') {
    content = escapeHTML(content)
  }

  return `${htmlTag('meta', {
    name,
    content
  })}\n`
}

function og (name, content, escape) {
  if (escape !== false && typeof content === 'string') {
    content = escapeHTML(content)
  }

  return `${htmlTag('meta', {
    property: name,
    content
  })}\n`
}

function openGraphHelper (options = {}) {
  const { config, page, theme } = this
  const { content } = page
  let images = page.photos || []
  let description = page.excerpt || theme.description
  const keywords = page.keywords || (page.tags && page.tags.length ? page.tags : undefined) || config.keywords
  const title = page.title || theme.nickname
  const type = (this.is_post() ? 'article' : 'website')
  const url = this.url.replace(/index.html$/, '')
  const siteName = theme.nickname
  const twitterCard = options.twitter_card || 'summary'
  const published = page.date || false
  const updated = page.lastUpdated || false
  const language = options.language || page.lang || page.language || config.language
  let result = ''

  if (!Array.isArray(images)) images = [images]

  if (description) {
    description = stripHTML(description).substring(0, 200)
      .trim() // Remove prefixing/trailing spaces
      .replace(/</g, '&lt;')
      .replace(/>/g, '&gt;')
      .replace(/&/g, '&amp;')
      .replace(/"/g, '&quot;')
      .replace(/'/g, '&apos;')
      .replace(/\n/g, ' ') // Replace new lines by spaces
  }

  if (!images.length && content && content.includes('<img')) {
    images = images.slice()

    if (!cheerio) cheerio = require('cheerio');
    const $ = cheerio.load(content)

    $('img').each((index, element) => {
      const src = $(element).attr('data-src')
      if (src) images.push(src)
    })
  }

  if (description) {
    result += meta('description', description, false)
  }

  if (keywords) {
    if (typeof keywords === 'string') {
      result += meta('keywords', keywords)
    } else if (keywords.length) {
      result += meta('keywords', keywords.map(tag => {
        return tag.name ? tag.name : tag
      }).filter(keyword => !!keyword).join())
    }
  }

  result += og('og:type', type)
  result += og('og:title', title)
  result += og('og:url', url, false)
  result += og('og:site_name', siteName)
  if (description) {
    result += og('og:description', description, false)
  }

  if (language) {
    result += og('og:locale', language, false)
  }

  images = images.map(path => {
    if (!new URL(path).host) {
      // resolve `path`'s absolute path relative to current page's url
      // `path` can be both absolute (starts with `/`) or relative.
      return new URL(path, url || config.url)
    }

    return path
  })

  images.forEach(path => {
    result += og('og:image', path, false)
  })

  if (published) {
    if ((moment.isMoment(published) || moment.isDate(published)) && !isNaN(published.valueOf())) {
      // Skip timezone conversion
      result += og('article:published_time', moment(published).format('YYYY-MM-DD[T00:00:00.000Z]'))
    }
  }

  if (updated) {
    if ((moment.isMoment(updated) || moment.isDate(updated)) && !isNaN(updated.valueOf())) {
      result += og('article:modified_time', moment(updated).format('YYYY-MM-DD[T00:00:00.000Z]'))
      result += og('og:updated_time', moment(updated).format('YYYY-MM-DD[T00:00:00.000Z]'))
    }
  }

  result += meta('twitter:card', twitterCard)

  if (images.length) {
    result += meta('twitter:image', images[0], false)
  }

  return result.trim()
}

hexo.extend.helper.register('openGraph', openGraphHelper)