fixposts.js

/**
 * From previous conversions from WordPress to Ghost, I have a lot of posts
 * with links to other posts, where the link is actually incorrect. The
 * incorrect links are missing the day (dd) part of the URL.
 *
 * This script is a quick and dirty way of fixing them, in-place:
 * 1) read all the posts, and work out a slug-to-anchor mapping
 * 2) go through all the posts, using regexes to find incorrect links
 *    and replace them with the correct ones, referencing the mapping
 *    from the first step.
 *
 * DJ Adams, Dec 2018
 */

const fs = require('fs')

const postsDirectory = '/home/qmacro/local/projects/website/_posts/'

/**
 * Read the directory of posts, and create a map of filenames, where
 * the properties are the slugs and the values are how we need to make
 * the links to those files in the markdown
 */
const files = fs.readdirSync(postsDirectory).reduce((a, x) => {

        // filenames look like this: yyyy-mm-dd-some-title-as-slug.markdown
        const parts = x.match(/^(\d{4}-\d{2}-\d{2})-(.+)\.markdown$/)

        // construct map entry, slug = yyyy/mm/dd/slug
        a[parts[2]] = [parts[1].split(/-/).join("/"),parts[2]].join("/")

        return a

}, {})


/**
 * This function to be called from replace function below
 * p1 is the first parentheses-captured value in the replace's regex
 * and represents the slug
 */
const replacer = function(_, p1) {
        return files[p1]
}

/**
 * Fix the markdown anchors to other local posts, for a given file
 */
function fixFile(filename) {
        fs.readFile(postsDirectory + filename, 'utf8', function(err, data) {
                if (err) return console.log(err)

                // Replace any existing, incorrect anchor references, they will look
                // like this: (/yyyy/mm/some-title-as-slug). Capture the slug on match.
                // Use zero-width lookbehind and lookahead assertions to ensure a proper match.
                var result = data.replace(/(?<=\(\/)20\d\d\/\d\d\/([^\/]+)(?=\/\))/g, replacer)

                // If there have been replacements, write the updated file contents
                if (result != data) {
                        console.log("Fixed " + filename)
                        fs.writeFile(postsDirectory + filename, result, 'utf8', function(err) {
                                if (err) return console.log(err)
                        })
                }
        })
}


fs.readdirSync(postsDirectory).forEach((x) => fixFile(x))