Update mc plugins defined in default.nix

update.py

#!/usr/bin/env python3
# -*- coding: utf-8 -*-
import logging
import re
import shlex
import subprocess

import requests
from bs4 import BeautifulSoup


logger = logging.getLogger().setLevel(logging.DEBUG)
# Hangar does not like the requests user agent, and sends back
# 404s for everything.
headers = {
    "User-Agent": "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/111.0.0.0 Safari/537.36",
}


def load_versions():
    with open("./default.nix", "r") as default_dot_nix:
        content = default_dot_nix.read()
        default_dot_nix.seek(0, 0)
        lines = default_dot_nix.readlines()

    on_plugins_list = False
    plugins = []
    for i, line in enumerate(lines):
        line = line.strip()

        if line.strip() == "plugins = [":
            on_plugins_list = True
            continue

        if on_plugins_list and "]" in line:
            break

        if on_plugins_list and line == "}":
            plugins.append(
                dict(
                    (
                        l.strip().replace('"', "").replace(";", "").split(" = ")
                        for l in lines[i - 3 : i]
                    )  # don't care about the hash
                )
            )

            logging.info("Found plugin " + str(plugins[-1]))

    return plugins, content


def get_redirect_url(url):
    r = subprocess.run(
        shlex.split(
            "curl -IsSfw '%{redirect_url}\n' " + url,
        ),
        capture_output=True,
    )

    if r.returncode != 0:
        raise OSError(f"Unable to get redirect url for {url}: {r.stderr}")

    lines = r.stdout.decode("utf-8").split("\n")
    redirect_url = lines[-2]

    if redirect_url == "\n" or not redirect_url.startswith("https:"):
        raise ValueError(f"Weird url: {r}")

    return redirect_url


def get_sha256_base64_hash(url):
    r = subprocess.run(
        shlex.split(
            "nix-prefetch-url " + url,
        ),
        capture_output=True,
    )
    if r.returncode != 0:
        raise OSError(f"Unable to prefetch url {url}: {r.stderr}")

    b32hash = r.stdout.decode("utf-8").strip()

    r = subprocess.run(
        shlex.split(
            "nix hash to-base64 --type sha256 " + b32hash,
        ),
        capture_output=True,
    )
    if r.returncode != 0:
        raise OSError(f"Unable to convert b32 hash {b32hash} to base64: {r.stderr}")

    b64hash = r.stdout.decode("utf-8").strip()

    return f"sha256-{b64hash}"


def handle_geyser_plugin(plugin):
    _parts = plugin["url"].split("/")
    version = _parts[-5]
    build = _parts[-3]

    latest_url = plugin["url"].replace(version, "latest").replace(build, "latest")
    redirect_url = get_redirect_url(latest_url)

    logging.debug(
        f"Plugin {plugin['name']}: "
        f"given={plugin['url']},latest={latest_url},"
        f"redirected_to={redirect_url}",
    )

    if redirect_url != plugin["url"]:
        _new_parts = redirect_url.split("/")
        new_version = _new_parts[-5]
        new_build = _new_parts[-3]

        logging.info(
            f"Geyser plugin {plugin['name']} has new version {version} and build {build}"
        )

        return redirect_url

    return None


def handle_hangar_plugin(plugin):
    _parts = plugin["url"].split("/")
    org = _parts[4]
    name = _parts[5]

    homepage_url = f"https://hangar.papermc.io/{org}/{name}"
    homepage = requests.get(homepage_url, headers=headers)
    if homepage.status_code != 200:
        raise ValueError(
            f"Unable to get url {homepage_url}, got status code {homepage.status_code}"
        )

    soup = BeautifulSoup(homepage.text, features="html.parser")
    download_url = soup.find(
        "a", href=lambda href: "hangarcdn.papermc.io" in href
    ).attrs["href"]

    logging.debug(
        f"Plugin {plugin['name']}: " f"given={plugin['url']}, " f"latest={download_url}"
    )

    if download_url != plugin["url"]:
        new_jar = download_url.split("/")[-1]
        logging.info(f"Hangar plugin {plugin['name']} has new jar {new_jar}")

        return download_url

    return None


def handle_modrinth_plugin(plugin):
    homepage_url = f"https://modrinth.com/plugin/{plugin['name']}/versions"
    homepage = requests.get(homepage_url, headers=headers)
    if homepage.status_code != 200:
        raise ValueError(
            f"Unable to get url {homepage_url}, got status code {homepage.status_code}"
        )

    download_url = None
    soup = BeautifulSoup(homepage.text, features="html.parser")

    # Find the first download button (class "version-button") that:
    #   1. Is marked as a stable release (nested <a> tag contains the class "release")
    #   2. Has a <span> tag containing the string "Paper" (targets a nested <div>
    #      tag with the class "version__supports", containing the supported distros).
    latest_paper_button = soup.find(
        lambda tag: len(tag.findChildren("a", class_="release", recursive=False)) > 0
        and len(tag.findChildren("span", string=re.compile("Paper"))) > 0,
        class_="version-button",
    )

    if latest_paper_button is not None:
        download_url = latest_paper_button.find("a").attrs["href"]

    logging.debug(
        f"Plugin {plugin['name']}: " f"given={plugin['url']}, " f"latest={download_url}"
    )

    if download_url is not None and download_url != plugin["url"]:
        new_jar = download_url.split("/")[-1]
        logging.info(f"Modrinth plugin {plugin['name']} has new jar {new_jar}")

        return download_url

    return None


if __name__ == "__main__":
    plugins, default_dot_nix = load_versions()
    for plugin in plugins:
        handler = None
        if "geyser" in plugin["url"]:
            handler = handle_geyser_plugin
        elif "hangar" in plugin["url"]:
            handler = handle_hangar_plugin
        elif "modrinth" in plugin["url"]:
            handler = handle_modrinth_plugin
        else:
            raise TypeError("unknown plugin type", plugin)

        new_url = handler(plugin)
        if new_url is not None:
            default_dot_nix = default_dot_nix.replace(plugin["url"], new_url)
            default_dot_nix = default_dot_nix.replace(
                plugin["hash"], get_sha256_base64_hash(new_url),
            )

    with open("default.nix.updated", "w") as default_dot_nix_new:
        default_dot_nix_new.write(default_dot_nix)