Migrating data from Ghost to GatsbyJS

What is Gatsby?

🔥 Blazing-fast static site generator for React

It's is perfect for a static blog, it reads markdown and gives you a GraphQL API to query it and a React front end.

Coupled with https://www.netlify.com/, it is a fantastic solution from development to deployment.

I've used Ghost for my blogs for years but I decided to migrate across recently. So how did I do it?

Ghost allows your to export your data in a big JSON blob. So the question is how do you turn this into something that Gatsby can consume?

Parse that shiz

I wrote a small node app to take the data exported by Ghost and parse it into the markdown files/folders that Gatsby expects.

First of all, you have to look at the fomat of a gastby blog post.

---
title: Hello world
date: 2016-04-15T14:32:57.000Z
slug: /hello-world/
---

### I'm a blog title

And I'm some text

Then have a look at what Ghost exports.

I was using an older version of Ghost so the exact format might have changed but here was the gist of my output.

{
	"db": [
		"data": {
			"posts": [
				{
					published_at: "2018-06-18T10:09:09",
					slug: "hello-world",
					markdown: "# I'm a blog title\n And I'm some text",
					title: "Hello world"
				}
			]
		}
	]
}

So to begin parsing, I first made an ES6 template string in the shape of the output format.

const template = `---
title: "${title}"
date: "${published_at}"
slug: "/${slug}/"
---
${markdown}
`;

Then I realised that the published_at date is in the wrong format so I had to parse that into the correct format so

date: '${published_at}';

becomes

date: '${new Date(published_at).toISOString()}';

I want to put these in a folder which I've already made called blog-posts

$ mkdir blog-posts

And I want each blog post to go into a folder named in the format {year}-{month}-{day}-{slug} as I'll be calling the markdown files index.md.

So to do this, I've used fs.mkdirSync. I'm not too worried about speed here so I've opted for the simpler synchronous implementation version of fs.mkdir.

const publishedAt = new Date(published_at);
const day = publishedAt.getDate();
const month = publishedAt.getMonth() + 1; // months go from 0 (jan) to 11 (dec) so pad by 1
const year = publishedAt.getFullYear();
const folderName = `${year}-${month}-${day}-${slug}`;

fs.mkdirSync(`./blog-posts/${folderName}`);

All that's left to do now is to write the filled template to file within our new folder. Again, I've opted for the syncronous version of fs.writeFile for simplicity.

fs.writeFileSync(`./blog-posts/${folderName}/index.md`, template, 'utf8');

I put all of this inside a function called parseBlogPost and passed it into the forEach on the posts.

blog.db[0].data.posts.forEach(parseBlogPost);

The code is available in Github, feel free to fork it and update it for future versions of Ghost if you want.