racket: add updateScript

pkgs/development/interpreters/racket/default.nix

@@ -185,6 +185,11 @@ stdenv.mkDerivation (finalAttrs: {
 
   passthru = {
     # Functionalities #
+    updateScript = {
+      command = ./update.py;
+      attrPath = "racket";
+      supportedFeatures = [ "commit" ];
+    };
     writeScript =
       nameOrPath:
       {

pkgs/development/interpreters/racket/update.py

@@ -0,0 +1,73 @@
+#! /usr/bin/env nix-shell
+#! nix-shell -i python3 --packages 'python3.withPackages (ps: with ps; [ requests beautifulsoup4 ])'
+import os
+import re
+import json
+import requests
+from bs4 import BeautifulSoup
+
+SITE = "https://download.racket-lang.org"
+MANIFEST_FILENAME = "manifest.json"
+
+def find_info(table, group_name, subgroup_name):
+    group = table.find(
+        string=re.compile("^{}\\s*".format(group_name))
+       ).find_parent("tr", class_="group")
+    subgroup = group.find_next(
+        string=re.compile("^{}\\s*".format(subgroup_name))
+       ).find_parent(class_="subgroup")
+    link = subgroup.find_next(
+        "a",
+        class_="installer",
+        string="Source"
+       )
+    filename = link["href"].split("/")[1]
+    sha256 = link.find_next(class_="checksum").string
+
+    return {
+        "filename": filename,
+        "sha256": sha256,
+    }
+
+os.chdir(os.path.dirname(os.path.abspath(__file__)))
+
+prev_version = os.environ["UPDATE_NIX_OLD_VERSION"]
+
+homepage = BeautifulSoup(requests.get(SITE).text, "html.parser")
+
+version = homepage.find(
+    "h3",
+    string=re.compile("^Version \\d+\\.\\d+")
+).string.split()[1]
+if version == prev_version:
+    raise Exception("no newer version available")
+
+down_page_path = homepage.find(
+    "a",
+    string="More Installers and Checksums"
+)["href"]
+down_page = BeautifulSoup(requests.get(SITE + "/" + down_page_path).text, "html.parser")
+down_table = down_page.find(class_="download-table")
+
+full = find_info(down_table, "Racket", "Unix")
+minimal = find_info(down_table, "Minimal Racket", "All Platforms")
+
+with open(MANIFEST_FILENAME, "w", encoding="utf-8") as f:
+    json.dump({
+        "version": version,
+        "full": full,
+        "minimal": minimal,
+    }, f, indent=2, ensure_ascii=False)
+    f.write("\n")
+
+print(json.dumps(
+    [
+        {
+            "attrPath": os.environ["UPDATE_NIX_ATTR_PATH"],
+            "oldVersion": prev_version,
+            "newVersion": version,
+            "files": [ os.path.abspath(MANIFEST_FILENAME) ],
+        },
+    ],
+    indent=2, ensure_ascii=False
+))