Tuesday, 18 December, 2018 UTC


This blogpost explains how I learned to reduce the cost of maintaining a simple brochure or blog site. When using Drupal, you need at least a shared hosting platform (there is no Wordpress.com for Drupal sites). So, migrating to a static site generator, like Jekyll or Gatsby, seemed like a good idea. Gatsby is also a great opportunity to learn React and then get hosting for free using something like GitHub Pages. This post is going to describe how to migrate a simple blog—that has featured images on the posts, comments and tags—from Drupal to Gatsby.
To facilitate exporting the site, the first thing I did was export the database from the mysql database server to an sqlite file that I could use locally. To do this I used the mysql2sqlite project, which, as described on the project page, can be done with two commands like:
mysqldump --skip-extended-insert --compact DB_name > dump_mysql.sql ./mysql2sqlite dump_mysql.sql | sqlite3 mysqlite.db
How to export a Drupal site to Gatsby yourself
To do this yourself, you’ll build a simple blog using the excellent gatsby-starter-blog project. Create a new project and then add a sqlite library as a dev dependency:
gatsby new gatsby-blog https://github.com/gatsbyjs/gatsby-starter-blog git init # so you can keep track of the changes npm i --save-dev better-sqlite3
The useful commands on an sqlite3 command line to explore are .tables to see all tables :) and .schema table_name to see information about a specific table. Oh! and .help to know more.
Next, you will be creating a new file on your project at src/scripts/migrate.js. Initially, what you want is to iterate through all your posts and export basic data like title, created date, body and status (published or draft). All of that data is in two tables, the node table and the fielddatabody. Initially, your script will look like this:
const Database = require('better-sqlite3'); const fs = require('fs'); const http = require('http'); // argv[2] would be the first argument passed to > node src/scripts/import.js [database.db] const db = new Database(process.argv[2], {readonly: true}); const rows = db.prepare(`SELECT n.nid, n.title, n.created, b.body_value, n.status FROM node n INNER JOIN field_data_body b ON b.entity_id = n.nid`).all(); rows.forEach(row => { // taken from: https://gist.github.com/matthagemann/382adfc57adbd5af078dc93feef01fe1 const slug = slugify(row.title); const folder = row.status ? '/../pages/' : '/../../drafts/'; const path = __dirname + folder + slug; // timestamp in Drupal is in seconds, Date() expects microseconds const date = new Date(row.created * 1000);
The interesting thing here is the initial query, and this is based on a Drupal 7 database. A Drupal 8 or Drupal 6 database could be different, so check your schema. Next, load the tags on a simple Javascript array. Each post can have more than one tag, so you can take advantage of better-sqlite’s .pluck() function, which retrieves only the first column of a database query, and the .all() function, which retrieves all rows in a single array:
const tags = db .prepare( `SELECT td.name FROM taxonomy_index ti INNER JOIN taxonomy_term_data td ON td.tid = ti.tid AND ti.nid = ? WHERE ti.tid NOT IN (SELECT tid FROM taxonomy_index GROUP BY tid HAVING count(nid) = 1)` ) .pluck() .all(row.nid)
For the image, you will retrieve only the URL of the image, so you can download it and store it locally. And you will replace public:// for the URL path of the images folder on your old site:
let image = db .prepare( `SELECT filename, uri FROM field_data_field_image i INNER JOIN file_managed f ON f.fid = i.field_image_fid WHERE i.entity_id = ?` ) .get(row.nid) if (image) { image.uri = image.uri.replace("public://", "http://myblog.com/files/") }
And now that you have all the data you need, it is just a matter of creating a file with the metadata in yaml format and the body of the text in Markdown format. Luckily, a Drupal blog can also use Markdown or you can also look for an HTML to Markdown Javascript library like turndown.
 fs.mkdir(path, (err) => { }); const file = fs.createWriteStream(path + '/index.md', { flags: 'w' }); // This is here incase any errors occur file.on('open', function () { file.write('---\n'); file.write('title: "' + row.title + '"\n'); file.write('date: "' + date.toISOString() + '"\n'); file.write('aliases: ' + JSON.stringify(aliases) + '\n'); file.write('tags: ' + JSON.stringify(tags) + '\n'); file.write('---\n\n'); if (image) { // taken from: https://stackoverflow.com/a/22907134/9055 download(image.uri, path + '/' + image.filename); file.write(`![${image.filename}](./${image.filename})\n\n`); } file.write(row.body_value); file.end(); }); console.log(date, slug, JSON.stringify(aliases)); }); db.close();
This script is now finished and you can execute it in your shell with this command:
> node src/scripts/import.js mysqlite.db
To have comments on your site you can use a service like Disqus. Disqus has an import process that uses a custom XML import format based on the WXR (WordPress eXtended RSS) schema. So the process would be the same. Create a script named src/scripts/export_comments.js to query the database and, in this case, write a single file containing all the comments of your old site:
const Database = require("better-sqlite3") const fs = require("fs") const yourSite = "http://username.github.io/yoursite/" if (process.argv.length < 3) { usage() process.exit() } const db = new Database(process.argv[2], { readonly: true }) const rows = db .prepare( `SELECT n.nid, n.title, n.created, b.body_value, n.status, c.cid, c.pid, c.name, c.mail, c.created created_comment, c.homepage, c.hostname, c.subject, cb.comment_body_value FROM node n INNER JOIN field_data_body b ON b.entity_id = n.nid INNER JOIN comment c ON c.nid = n.nid AND c.status = 1 INNER JOIN field_data_comment_body cb ON cb.entity_id = c.cid ORDER BY n.nid, c.cid` ) .all() console.log(`<?xml version="1.0" encoding="UTF-8"?> <rss version="2.0" xmlns:content="http://purl.org/rss/1.0/modules/content/" xmlns:dsq="http://www.disqus.com/" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:wp="http://wordpress.org/export/1.0/" > <channel>`) let previous_slug = "" rows.forEach(row => { const slug = slugify(row.title) const date = new Date(row.created * 1000) const date_comment = new Date(row.created_comment * 1000) if (slug != previous_slug) { if (previous_slug != "") { console.log(`</item>`) } console.log(`<item> <title>${row.title}</title> <link>${yourSite}${slug}</link> <content:encoded><![CDATA[${row.body_value}]]></content:encoded> <dsq:thread_identifier>${row.nid}</dsq:thread_identifier> <wp:post_date_gmt>${getDisqusDate(date)}</wp:post_date_gmt> <wp:comment_status>open</wp:comment_status>`) previous_slug = slug } console.log(` <wp:comment> <wp:comment_id>${row.cid}</wp:comment_id> <wp:comment_author>${row.name}</wp:comment_author> <wp:comment_author_email>${row.mail}</wp:comment_author_email> <wp:comment_author_url>${row.homepage}</wp:comment_author_url> <wp:comment_author_IP>${row.hostname}</wp:comment_author_IP> <wp:comment_date_gmt>${getDisqusDate(date_comment)}</wp:comment_date_gmt> <wp:comment_content><![CDATA[${ row.comment_body_value }]]></wp:comment_content> <wp:comment_approved>1</wp:comment_approved> <wp:comment_parent>${row.pid}</wp:comment_parent> </wp:comment> `) }) console.log(`</item></channel></rss>`) db.close() function usage() { const path = require("path") const scriptName = path.basename(__filename) console.log("node " + scriptName + " <database.sqlite>") } function getDisqusDate(date) { return ( date.toISOString().slice(0, 10) + " " + date.toISOString().slice(11, 19) ) } function slugify(string) { const a = "àáäâãåèéëêìíïîòóöôùúüûñçßÿœæŕśńṕẃǵǹḿǘẍźḧ·/_,:;" const b = "aaaaaaeeeeiiiioooouuuuncsyoarsnpwgnmuxzh------" const p = new RegExp(a.split("").join("|"), "g") return string .toString() .toLowerCase() .replace(/\s+/g, "-") // Replace spaces with .replace(p, c => b.charAt(a.indexOf(c))) // Replace special characters .replace(/&/g, "-and-") // Replace & with ‘and’ .replace(/[^\w\-]+/g, "") // Remove all non-word characters .replace(/\-\-+/g, "-") // Replace multiple — with single - .replace(/^-+/, "") // Trim — from start of text .replace(/-+$/, '') // Trim — from end of text }
Run node src/scripts/export_comments.js ../mysqlite.db > comments.xml and that’s it. This will generate a comments.xml file that you can import into disqus. Just remember to change the yourSite variable in the script, and it will link each comment to the correct post in your new blog using the slug used in the posts import.
You now have all the posts and all comments ready to be used on your Gatsby blog. You can see a working example here: https://github.com/jackbravo/joaquin.axai.mx.