Add git-download-subpath

content/posts/git-download-subpath/index.md

@@ -0,0 +1,78 @@
+---
+title: "git download-subpath"
+emoji: 🤓
+date: 2024-05-14T13:08:10+01:00
+summary: I made a git helper tool that lets you retrieve files from a subpath of git without downloading the whole of the (possibly huge) repo.
+tags:
+- git
+- computers
+- tools
+syndications:
+- https://gist.github.com/jphastings/6560bb173399fc3a155913b33e5f0f0c
+---
+
+My blog has ~250MB of [photos](/photos) in it (as I [archived my Instagram here](/posts/archiving-instagram-posts/) — _a decade_ of photos) which means that every time I want some files from [my blog's repo](https://github.com/by-jp/www.byjp.me) I've needed to pull down all that data to get at the files I want.
+
+This isn't a problem on my laptop where I work on my blog (as it's already cloned), but I also keep my [IndieKit](https://getindiekit.com) config in there, and I don't want to have to clone an increasingly large repo every time.
+
+So I built `git-download-subpath`, which is a bash script around [git's partial clone](https://git-scm.com/docs/partial-clone) functionality.
+
+```bash
+$ git download-subpath
+# usage: git-download-subpath <repo> <subpath> [destination]
+
+$ git download-subpath https://github.com/by-jp/www.byjp.me indiekit
+# Successfully downloaded to ./indiekit
+```
+
+This script (which you can find & download below) completes these steps:
+
+1. Clones a "no tree" copy of the repo to a temporary directory (just references to commits & the latest files, not the data itself)
+2. Completes a "no cone" sparse checkout of the subpath desired
+3. Moves that desired subpath over the working directory (or the destination, if specified)
+
+I'm no bash expert, so there may be subtle bugs here; let me know if you spot them!
+
+_Copy the following bash to `git-download-subpath` somewhere in your `$PATH` (I keep it in `/usr/local/bin`), and mark as executable with `chmod +x git-download-subpath`:_
+
+```bash /usr/local/bin/git-download-subpath
+#!/bin/bash
+set -e
+
+repo="$1"
+subpath="$2"
+if [[ -z "${repo}" || -z "${subpath}" ]]; then
+  echo "usage: git-download-subpath <repo> <subpath> [destination]"
+  exit 1
+fi
+
+if [[ -z "$3" ]]; then
+  dest=$(pwd)
+else
+  dest=$(realpath "$3")
+fi
+if [[ ! -d "${dest}" ]]; then
+  >&2 echo "${dest} is not a directory that exists"
+  exit 3
+fi
+if [[ -d "${dest}/${subpath}" ]]; then
+  >&2 echo "${dest}/${subpath} already exists, exiting to avoid replacing"
+  exit 3
+fi
+
+# Cross-platform create temporary dir: https://unix.stackexchange.com/a/84980/
+tmpdir=$(mktemp -d 2>/dev/null || mktemp -d -t 'git-download-subpath')
+cd "${tmpdir}"
+
+git clone -n --depth=1 --filter=tree:0 "${repo}" repo > /dev/null 2>&1
+cd repo
+git sparse-checkout set --no-cone "${subpath}" > /dev/null 2>&1
+git checkout > /dev/null 2>&1
+if [[ ! -d "${subpath}" ]]; then
+  >&2 echo "The directory '${subpath}' doesn't exist in this repo."
+  exit 5
+fi
+cp -r "${subpath}" "${dest}/"
+
+echo "Successfully downloaded to ${dest}/${subpath}"
+```

layouts/partials/syndication.html

@@ -17,7 +17,9 @@
   {{ else if hasPrefix . "https://trakt.tv/" }}
     {{ partial "syndication-ref.html" (dict "type" "trakt" "link" .) }}
   {{ else if hasPrefix . "https://medium.com/" }}
-    {{ partial "syndication-ref.html" (dict "type" "medium" "link" .) }}  
+    {{ partial "syndication-ref.html" (dict "type" "medium" "link" .) }}
+  {{ else if hasPrefix . "https://gist.github.com/" }}
+    {{ partial "syndication-ref.html" (dict "type" "github" "link" .) }} 
   {{ else if hasPrefix . "https://soundcloud.com/" }}
     {{ partial "syndication-ref.html" (dict "type" "soundcloud" "link" .) }}
   {{ else if hasPrefix . "https://vimeo.com/" }}