From 2991c30e20ee5422e81c1ab9f4795e977c362508 Mon Sep 17 00:00:00 2001
From: JP Hastings-Spital <jphastings@gmail.com>
Date: Tue, 16 Jul 2024 13:15:04 +0100
Subject: [PATCH] Crypto-generated shortlink

- Every page now has a shortlink
- Shortlinks can be manually overridden with the shortlink frontmatter param
- A single "index.redirects" file is created at build time
- A "redirects" tool splits that one file into multiple `_redirects` files, as would be needed on a site like byjp.fyi
---
 config.toml                      | 12 +++++++++++-
 layouts/_default/index.redirects |  5 +++++
 layouts/partials/shortlink.txt   |  6 ++++++
 todo.md                          |  8 ++++++++
 tools/redirects/split.bash       | 16 ++++++++++++++++
 5 files changed, 46 insertions(+), 1 deletion(-)
 create mode 100644 layouts/_default/index.redirects
 create mode 100644 layouts/partials/shortlink.txt
 create mode 100755 tools/redirects/split.bash

diff --git a/config.toml b/config.toml
index 7adde8b3..1586baeb 100644
--- a/config.toml
+++ b/config.toml
@@ -189,6 +189,8 @@ date = ["date", "publishDate", "lastmod", ":git"]
     suffixes = ['opml.xml']
   [mediaTypes.'text/gemini']
     suffixes = ['gmi']
+  [mediaTypes.'text/plain+redirects']
+    suffixes = ['redirects']
 [outputFormats]
   [outputFormats.opml]
     mediaType = 'text/x-opml'
@@ -215,9 +217,17 @@ date = ["date", "publishDate", "lastmod", ":git"]
     permalinkable = false
     noUgly = false
     notAlternative = true
+  [outputFormats.redirects]
+    name = 'Redirects File'
+    isPlainText = true
+    isHTML = false
+    mediaType = 'text/plain+redirects'
+    permalinkable = false
+    noUgly = false
+    notAlternative = true
 
 [outputs]
-  home = ["html", "rss", "gemini"]
+  home = ["html", "rss", "gemini", "redirects"]
   page = ["html", "gemini"]
   rss = ["rss"]
   section = ["html", "rss", "gemini"]
diff --git a/layouts/_default/index.redirects b/layouts/_default/index.redirects
new file mode 100644
index 00000000..55b8502c
--- /dev/null
+++ b/layouts/_default/index.redirects
@@ -0,0 +1,5 @@
+{{ range .Site.RegularPages }}
+  {{- if .Permalink -}}
+    {{- printf "/%s %s 301\n" (partial "shortlink.txt" .) .Permalink -}}
+  {{- end -}}
+{{- end -}}
diff --git a/layouts/partials/shortlink.txt b/layouts/partials/shortlink.txt
new file mode 100644
index 00000000..4720e591
--- /dev/null
+++ b/layouts/partials/shortlink.txt
@@ -0,0 +1,6 @@
+{{- $shortlink := .Params.shortlink -}}
+{{- if not $shortlink -}}
+  {{/* TODO: Could convert to base36 to reduce size by 2 chars */}}
+  {{- $shortlink = printf "b/%s" (substr (.RelPermalink | crypto.MD5 ) 0 10) -}}
+{{- end -}}
+{{- $shortlink -}}
\ No newline at end of file
diff --git a/todo.md b/todo.md
index 28396d5d..78b64f65 100644
--- a/todo.md
+++ b/todo.md
@@ -29,6 +29,14 @@ Things I might work on within my personal blog's software.
 
 - [ ] Remove lychee failing links
 - [ ] Import Facebook posts
+- [ ] Shortlinks
+  - [x] All posts have an auto-generated unqiue shortlink
+  - [x] Allow for customisation of shortlinks
+  - [x] Create suitable `_redirects` files
+  - [ ] Import pre-existing shortlinks
+  - [ ] Add shortlink as `<link rel="shortlink">` on all relevant pages
+  - [ ] Upload new redirects to byjp.fyi repo
+  - [ ] Add additional logic to _combine_ the redirects files as needed
 
 ### Done ✓
 
diff --git a/tools/redirects/split.bash b/tools/redirects/split.bash
new file mode 100755
index 00000000..a0b85034
--- /dev/null
+++ b/tools/redirects/split.bash
@@ -0,0 +1,16 @@
+#!/bin/bash
+
+rm **/_redirects
+
+while IFS=$'\n' read -r line
+do
+  # Extract the absolute file path
+  outdir=$(dirname $(echo "$line" | cut -d " " -f1) | cut -d "/" -f2)
+
+  if [[ -n "$outdir" ]]; then
+    [[ ! -d $outdir ]] && mkdir -p $outdir
+    echo $line | cut -c $((${#outdir}+2))- >> "./$outdir/_redirects"
+  else
+    echo $line  >> "_redirects"
+  fi
+done < "${1:-/dev/stdin}"