Automatically update Joplin from GitHub

joplin-update.py

#!/usr/bin/env python3

import hashlib
import json
import re
import shutil
import subprocess
import tempfile
import urllib.request

USER_AGENT = "Joplin-Update/1.0"
GITHUB_RELEASES_API = "https://api.github.com/repos/laurent22/joplin/releases?per_page=10"
ASSET_NAME_REGEX = re.compile(".*\\.AppImage$")
HASH_NAME_REGEX = re.compile(".*\\.AppImage\\.sha512$")
INSTALL_PATH = "/usr/local/bin/joplin"

def request_json(url):
    headers = { "User-Agent": USER_AGENT, "Accept": "application/json" }
    request = urllib.request.Request(url, headers=headers)
    with urllib.request.urlopen(request) as json_result:
        return json.load(json_result)

def open_download(url):
    headers = { "User-Agent": USER_AGENT }
    request = urllib.request.Request(url, headers=headers)
    return urllib.request.urlopen(request)

def get_release_from_api():
    releases = request_json(GITHUB_RELEASES_API)

    version = ""
    download_url = ""
    hash = ""

    for release in releases:
        if not release["prerelease"]:
            version = release["name"]
            assets = release["assets"]
            for asset in assets:
                if ASSET_NAME_REGEX.match(asset["name"]):
                    download_url = asset["browser_download_url"]
                elif HASH_NAME_REGEX.match(asset["name"]):
                    with open_download(asset["browser_download_url"]) as hash_file:
                        hash = hash_file.read().decode()

            break

    if version and download_url and hash:
        return (version, download_url, hash)
    else:
        return None

api_release = get_release_from_api()

if api_release:
    (api_version, download_url, api_hash) = api_release
    with open(INSTALL_PATH, "rb") as system_file:
        system_hash = hashlib.file_digest(system_file, "sha512")
    if system_hash.hexdigest() == api_hash:
        print("Joplin appears to be up to date")
    else:
        print("Installing version: {}".format(api_version))
        with open_download(download_url) as download_file, \
            tempfile.NamedTemporaryFile(suffix=".AppImage", delete_on_close=False) as temp_file:
            shutil.copyfileobj(download_file, temp_file)
            temp_file.close()
            subprocess.run(["sudo", "mv", temp_file.name, INSTALL_PATH], check=True)
            subprocess.run(["sudo", "chmod", "755", INSTALL_PATH], check=True)
else:
    print("Could not get version from release feed")