Backlink map. When ran from the content folder of a hugo project will create a json file that maps the Url and Title of a page to any internal links inside it.

main.go

package main

import (
	"strings"
	"log"
	"os"
	"io/ioutil"
	"path/filepath"
	"encoding/json"
	"regexp"
)

type LinkMap struct {
    Source      string  `json:"source"`
    SourceTitle string  `json:"sourceTitle"`
    Target      string  `json:"target"`
}

func toUrl(path string) (string) {
	return "/" + strings.TrimSuffix(path, ".md") + "/"
}

func main() {
	var linkMaps []LinkMap
	outputFile := os.Args[1]

	err := filepath.Walk(".", func(path string, info os.FileInfo, err error) error {
		//for every markdown file find all links in the document and map them to the document name and title
		if strings.HasSuffix(path, ".md") {
			l := regexp.MustCompile(`!?\[([^\]]*)?\]\(((https?:\/\/)?[A-Za-z0-9\:\/\. ]+)(\"(.+)\")?\)`) // [link](pattern)
			t := regexp.MustCompile(`title: (.*)\n`) // YAML title

			content, err := ioutil.ReadFile(path)
			if err != nil {
				log.Print("failed to read: " + path)
				return err
			}
			log.Print("Reading " + path)

		    s := string(content)
			title := t.FindStringSubmatch(s)
			links := l.FindAllStringSubmatch(s, -1)
			
			for _, link := range links {
				if strings.HasSuffix(link[2], ".md") {
					log.Print("---> found link: " + link[2])

					newMap := LinkMap {toUrl(path), title[1], toUrl(link[2])}
					linkMaps = append(linkMaps, newMap)
				}
			}
		}
	
		return nil
	})

	if err != nil {
		log.Panic(err)
	}

	jsonLinks, err := json.Marshal(linkMaps)
	if err != nil{
		log.Panic(err)
	}

	err = os.WriteFile(outputFile, jsonLinks, 0644)
    if err != nil {
        log.Panic(err)
    }

}

I am then using this json file as data for hugo to render backlinks at the end of each post using something like this

    {{ $headerWritten := false }}
    {{ $links := site.Data.links }}
    {{ range $links }}
        {{ if eq .target $me }}
            {{ if not $headerWritten }}
                <h2>Backlinks</h2>
                {{ $headerWritten = true }}
            {{ end }}
            <a href="{{ .source }}">{{.sourceTitle}}</a><br/>
        {{ end }}
    {{ end }}```