Ghost Blog backup to Astro markdown - The Hard Way

index.js

const fs = require('fs');

fs.readFile('./data/backfile.json', 'utf8', (err, data) => {
  if (err) throw err;
  const backup = JSON.parse(data);
  processBackup(backup);
});

function processBackup(backup) {
  const posts = backup.db[0].data.posts;
  for (let i = 0; i < posts.length; i++) {
    const post = posts[i];
    const {
        title,
        html,
        feature_image,
        slug: postSlug,
        published_at: pubDatetime
    } = post;

    const markdown = convertHtmlToMarkdown(html);
    const metadata = {
      title,
      feature_image,
      postSlug,
      pubDatetime
    };
    saveAsMarkdownFile(title, markdown, metadata);
  }
}

const TurndownService = require('turndown');
const turndown = new TurndownService();

function convertHtmlToMarkdown(html) {
  return turndown.turndown(html);
}

function slugify(str) {
  return str
    .toLowerCase()
    .replace(/\s+/g, '-')  // Replace spaces with hyphens
    .replace(/[\/?…]+/g, '-')  // Replace forward slashes, question marks, and ellipses with hyphens
    .replace(/-+/g, '-')  // Replace multiple hyphens with a single hyphen
    .replace(/[^a-z0-9-]/g, '');  // Remove any remaining characters that are not alphanumeric or hyphens
}

function replaceGhostUrlPlaceholders(str) {
  // Remove __GHOST_URL__ from URLs
  let updatedStr = str.replace(/__GHOST_URL__\//g, '/');

  // Change /content/images to /assets/images
  updatedStr = updatedStr.replace(/\/content\/images/g, '../../assets/images');

  return updatedStr;
}

function saveAsMarkdownFile(title, markdown, metadata) {
  const pubDate = new Date(metadata.pubDatetime);
  const formattedDate = pubDate.toISOString().split('T')[0];  // Formats date as YYYY-MM-DD
  const fileName = `${formattedDate}-${slugify(title)}.md`;

  if (metadata.feature_image) { // convert feature image to ogImage, if it exists
    metadata.feature_image = replaceGhostUrlPlaceholders(metadata.feature_image);
    metadata.ogImage = metadata.feature_image;
  } else { // otherwise just delete this key
    delete metadata.feature_image;
  }

  // add an image tage for the featured image 
  const imageMarkdown = metadata.feature_image ? `![Featured Image](${metadata.feature_image})\n\n` : '';

  delete metadata.feature_image;

  const updatedMarkdown = replaceGhostUrlPlaceholders(markdown);

  const metadataUpdated = Object.entries(metadata)
    .map(([key, value]) => `${key}: ${value}`)
    .join('\n');


  const content = `---
${metadataUpdated}
featured: false
draft: false
tags:
  - relevant-tag
description:
  Placeholder description for imported post from Ghost Blog 
---

${imageMarkdown}${updatedMarkdown}
`;
  fs.writeFile(`./output/${fileName}`, content, err => {
    if (err) throw err;
  });
}

package.json

{
  "dependencies": {
    "turndown": "^7.1.2"
  }
}