capacities: add updateScript

pkgs/by-name/ca/capacities/package.nix

@@ -6,13 +6,11 @@
   lib,
 }:
 let
-  pname = "capacities";
-  version = "1.65.13";
+  inherit (lib.importJSON ./version.json) version url sha256;
 
-  src = fetchurl {
-    url = "https://web.archive.org/web/20260518194627/https://2vks4.upcloudobjects.com/capacities-desktop-app/Capacities-1.65.13.AppImage";
-    hash = "sha256-ATiX1h9hXmKMFtY6OEyZEoJ/SxJGgbj5/QZwFF1sfFQ=";
-  };
+  pname = "capacities";
+
+  src = fetchurl { inherit url sha256; };
 
   appimageContents = appimageTools.extract {
     inherit
@@ -56,6 +54,8 @@ appimageTools.wrapType2 {
     fi
   '';
 
+  passthru.updateScript = ./update.py;
+
   meta = {
     description = "Calm place to make sense of the world and create amazing things";
     homepage = "https://capacities.io/";

pkgs/by-name/ca/capacities/update.py

@@ -0,0 +1,35 @@
+#! /usr/bin/env nix-shell
+#! nix-shell -i python3 -p "python3.withPackages (p: [ p.waybackpy p.requests ])"
+
+from pathlib import Path
+import json
+import subprocess
+
+import requests
+import waybackpy
+
+# Upstream doesn't provide persistent versioned URLs so we put the download link in Wayback Machine to preserve it.
+
+user_agent = "nixpkgs-update-capacities/1 https://github.com/NixOS/nixpkgs"
+
+session = requests.Session()
+session.headers["User-Agent"] = user_agent
+
+response = session.get("https://repology.org/api/v1/project/capacities").json()
+latest_version = max(item["version"] for item in response)
+
+# the wayback machine may take some time to respond to our save request, so we fetch upstream's version here instead of trying to fetch directly from wayback machine.
+print("Prefetching...")
+upstream_url = f"https://2vks4.upcloudobjects.com/capacities-desktop-app/Capacities-{latest_version}.AppImage"
+sha256, unpack_path = subprocess.check_output(["nix-prefetch-url", "--print-path", upstream_url], universal_newlines=True).split("\n")[:2]
+
+print(f"Archiving version {latest_version}...")
+save_api = waybackpy.WaybackMachineSaveAPI(upstream_url, user_agent)
+saved_url = save_api.save()
+
+print("Writing version.json...")
+(Path(__file__).parent / "version.json").write_text(json.dumps({
+  "url": saved_url,
+  "sha256": sha256,
+  "version": latest_version,
+}, indent=2) + "\n")

pkgs/by-name/ca/capacities/version.json

@@ -0,0 +1,5 @@
+{
+  "url": "https://web.archive.org/web/20260518194627/https://2vks4.upcloudobjects.com/capacities-desktop-app/Capacities-1.65.13.AppImage",
+  "sha256": "sha256-ATiX1h9hXmKMFtY6OEyZEoJ/SxJGgbj5/QZwFF1sfFQ=",
+  "version": "1.65.13"
+}