gatsby-remark-link-summary

This plugin scrapes link nodes and replaces the link nodes to summary nodes that you designed using scraped data (e.g. og:title, og:image, og:description).

Example Output

This plugin can convert text links in a markdown file to links with images as follows:

from

[--small-card--](https://www.npmjs.com/package/gatsby-remark-link-summary)
[--large-card--](https://github.com/blyoa/gatsby-remark-link-summary)

to

Installation

npm install gatsby-remark-link-summary

Usage

// In your gatsby-config.js
plugins: [
  {
    resolve: `gatsby-transformer-remark`,
    options: {
      plugins: [
        {
          // put `gatsby-remark-link-summary` before `gatsby-remark-images`
          // if generated nodes by `generator` includes img elements and
          // the image nodes should be processed by `gatsby-remark-images`
          resolve: `gatsby-remark-link-summary`,
          options: {
            cacheRootDirPath: 'path/to/cache',
            destinationSubDirPath: 'path/to/sub/dir',
            sites: [
              {
                pattern: /^https:\/\/github\.com\/.*/,
                generator: async ({ metadata: { url, title, image }, cacheRemoteFile }) => {
                  const deployedPath = await cacheRemoteFile(image, true)
                  return `<a href="${url}"><img src="${deployedPath}"/></a>`
                },
                rules: [
                  require('metascraper-url')(),
                  require('metascraper-image')(),
                ],
                gotOptions: {
                  // e.g.
                  // timeout: ...
                  // retry: ...
                },
                cacheExpirationSecond: 60 * 60 * 24 * 10, // 10 days
              },
              {
                // replace link nodes that have the text "--summary-card--"
                // e.g.
                // [--summary-card--](https://example.com)
                pattern: (node) => {
                  if (node.children.length === 0) return false
                  const [firstChild] = node.children
                  return  (firstChild.type === 'text' && firstChild.value === '--summary-card--')
                  // NOTE: The URL of a link node can be obtained from `node.url`
                },
                generator: async ({ metadata: { url, title, image }, cacheRemoteFile }) => {
                  const deployedPath = await cacheRemoteFile(image, true)
                  return `<a href="${url}"><img src="${deployedPath}"/></a>`
                },
                rules: [
                  require('metascraper-url')(),
                  require('metascraper-image')(),
                ],
              },
            ],
          },
        },
      ],
    },
  },
],

Options

| name | type | description | |:---|:---|:---| | cacheRootDirPath | string \| undefined | A directory to place remote files fetched by cacheRemoteFile of HTMLGeneratorParams and a catalog file about the fetched files and scraped metadata. If this option is undefined, the catalog file is not saved. | | destinationSubDirPath | string | A subdirectory of the directory for built artifacts (i.e., the public directory) to place remote files fetched in the second argument of generator. | | sites | SiteOptions[] | Node generator options for sites. |

SiteOptions

| name | type | description | |:---|:---|:---| | pattern | RegExp \| (node: Link) => boolean | A target link node to be substituted. RegExp specifies URLs of the link node to be substituted, and the function returns whether the link node should be substituted or not. Link is the type defined in mdast package. | | generator | (params: HTMLGeneratorParams) => string \| Node \| Promise<string \| Node> | A function to generate the node that substitute a link node. | | rules | Rule[] | Rules for metascraper. | | gotOptions | Options[] \| undefined | Options for got. | | cacheExpirationSecond | number \| undefined | The expiration second of scraped metadata and fetched remote files. The metadata and the path to the fetched remote file are reused until this expiration second reaches.If this option is undefined, the fetched metadata and the fetched remote files never expire. |

HTMLGeneratorParams

| name | type | description | |:---|:---|:---| | metadata | Record<string, string> | Metadata scraped by metascraper. | | orignalNode | Link | An original link node that generator substitutes. | | cacheRemoteFile | (fileURL: string, persistent?: boolean) => Promise<string> | A function to fetch a remote file and returns the path to the fetched file in destinationSubDirPath. fileURL is the URL of the remote file. When persistent is true, the fetched file is also saved in cachedRootDirPath. |

Example Settings

Card With Small Image

gatsby-config.js

const descriptionRule = require("metascraper-description")
const imageRule = require("metascraper-image")
const titleRule = require("metascraper-title")
const urlRule = require("metascraper-url")

module.exports = {
  // snip...
  plugins: [
    // snip...
    {
      resolve: `gatsby-transformer-remark`,
      options: {
        plugins: [
          {
            resolve: `gatsby-remark-link-summary`,
            options: {
              cacheRootDirPath: "cache/link-summary",
              destinationSubDirPath: "link-summary",
              sites: [
                {
                  pattern: /^https:\/\/www\.npmjs\.com\/.*/,
                  generator: async ({
                    metadata: { image, url, title, description },
                    cacheRemoteFile,
                  }) => {
                    const filePath = await cacheRemoteFile(image, true)
                    return `
                      <div class="summary-card">
                        <a href="${url}">
                          <img
                            class="summary-card__image"
                            src="${filePath}"
                          />
                          <div class="summary-card__description">
                            <div class="summary-card__description__title"
                              >${title}</div
                            >
                            <div class="summary-card__description__summary"
                              >${description}</div
                            >
                            <div class="summary-card__description__url"
                              >${url}</div
                            >
                          </div>
                        </a>
                      </div>
                    `
                  },
                  rules: [
                    urlRule(),
                    titleRule(),
                    imageRule(),
                    descriptionRule(),
                  ],
                },
              ],
            },
          },
          // snip...
        ],
      },
    },
    // snip...
  ],
}

your-style-file.css

/* import css, e.g. from gatsby-browser.js */
.summary-card {
  line-height: 1.5;
}

.summary-card a {
  color: inherit;
  text-decoration: none;
  display: flex;
  flex-direction: row-reverse;
  align-items: center;
  border: 1px solid #e5e5e5;
  border-radius: 3px;
}

.summary-card__image {
  width: 14rem;
  height: 10rem;
  object-fit: cover;
  border-inline-start: 1px solid #e5e5e5;
}

.summary-card__description {
  display: flex;
  flex-direction: column;
  flex: 1;
  padding: 0 1.2rem;
  overflow: hidden;
}

.summary-card__description__title {
  display: -webkit-box;
  -webkit-box-orient: vertical;
  -webkit-line-clamp: 2;
  font-weight: 700;
  max-height: calc(2rem * 1.5);
  overflow: hidden;
}

.summary-card__description__summary {
  display: -webkit-box;
  -webkit-box-orient: vertical;
  -webkit-line-clamp: 2;
  margin-block-start: 0.4rem;
  font-size: 0.8rem;
  max-height: calc(1.6rem * 1.5);
  overflow: hidden;
  color: #a3a3a3;
}

.summary-card__description__url {
  margin-block-start: 0.6rem;
  font-size: 0.8rem;
  overflow: hidden;
  text-overflow: ellipsis;
  color: #a3a3a3;
}

Card With Large Image

gatsby-config.js

const descriptionRule = require("metascraper-description")
const imageRule = require("metascraper-image")
const titleRule = require("metascraper-title")
const urlRule = require("metascraper-url")

module.exports = {
  // snip...
  plugins: [
    // snip...
    {
      resolve: `gatsby-transformer-remark`,
      options: {
        plugins: [
          {
            resolve: `gatsby-remark-link-summary`,
            options: {
              cacheRootDirPath: "cache/link-summary",
              destinationSubDirPath: "link-summary",
              sites: [
                {
                  pattern: /^https:\/\/github\.com\/.*/,
                  generator: async ({
                    metadata: { image, url, title, description },
                    cacheRemoteFile,
                  }) => {
                    const filePath = await cacheRemoteFile(image, true)
                    return `
                      <div class="large-image-summary-card">
                        <a href="${url}">
                          <img
                            class="large-image-summary-card__image"
                            src="${filePath}"
                          />
                          <div class="large-image-summary-card__description">
                            <div class="large-image-summary-card__description__title"
                              >${title}</div
                            >
                            <div class="large-image-summary-card__description__summary"
                              >${description}</div
                            >
                            <div class="large-image-summary-card__description__url"
                              >${url}</div
                            >
                          </div>
                        </a>
                      </div>
                    `
                  },
                  rules: [
                    urlRule(),
                    titleRule(),
                    imageRule(),
                    descriptionRule(),
                  ],
                },
              ],
            },
          },
          // snip...
        ],
      },
    },
    // snip...
  ],
}

/* import css, e.g. from gatsby-browser.js */
.large-image-summary-card {
  line-height: 1.5;
}

.large-image-summary-card a {
  display: flex;
  color: inherit;
  text-decoration: none;
  flex-direction: column;
  border: 1px solid #e5e5e5;
  border-radius: 3px;
}

.large-image-summary-card__image {
  width: 100%;
  object-fit: cover;
  border-block-end: 1px solid #e5e5e5;
}

.large-image-summary-card__description {
  display: flex;
  flex: 1;
  flex-direction: column;
  padding: 1.2rem;
}

.large-image-summary-card__description__title {
  display: -webkit-box;
  -webkit-box-orient: vertical;
  -webkit-line-clamp: 2;
  font-weight: 700;
  max-height: calc(2rem * 1.5);
  overflow: hidden;
}

.large-image-summary-card__description__summary {
  display: -webkit-box;
  -webkit-box-orient: vertical;
  -webkit-line-clamp: 2;
  margin-top: 0.2rem;
  font-size: 0.8rem;
  max-height: calc(1.6rem * 1.5);
  overflow: hidden;
  color: #a3a3a3;
}

.large-image-summary-card__description__url {
  margin-top: 0.4rem;
  font-size: 0.8rem;
  color: #a3a3a3;
  overflow: hidden;
  text-overflow: ellipsis;
}