main.py

from flask import Flask
from flask_restful import Resource, Api
import requests

app = Flask(__name__)
api = Api(app)

GITHUB_RELEASE_URL = "https://api.github.com/repos/sophosia/sophosia-releases/releases/latest"

PLATFORMS = [ # platform, extension
    (("linux-x86_64",), "amd64.AppImage.tar.gz"),
    (("darwin-x86_64", "darwin-aarch64"), "app.tar.gz"),
    (("windows-x86_64",), "x64_en-US.msi.zip"),
]

def get_latest_gh_release() -> dict:
    """
        Return format:
        Note darwin-aarch64 is silicon macOS. Supposed to seperate file but assumed that x64 would work due to Rosetta Stone 2
        {
          "version": "v0.1.0",
          "notes": "Test updater",
          "pub_date": "2022-11-13T03:20:32Z",
          "platforms": {
            "linux-x86_64": {
              "url": "https://github.com/sophosia/sophosia-releases/releases/download/v0.1.0/sophosia_0.1.0_amd64.AppImage.tar.gz",
              "signature": "content of .sig file"
            },
            "darwin-x86_64": {
              "url": "https://github.com/sophosia/sophosia-releases/releases/download/v0.1.0/sophosia_x64.app.tar.gz",
              "signature": "content of .sig file"
            },
            "windows-x86_64": {
              "url": "https://github.com/sophosia/sophosia-releases/releases/download/v1.0.8/sophosia_0.1.0_x64_en-US.msi.zip",
              "signature": "content of .sig file"
            }
          }
        }
    """
    try:
        release = requests.get(GITHUB_RELEASE_URL).json()
    except requests.RequestException:
        return {}
    release_response = {
        "version": release["tag_name"],
        "notes": release["body"].rstrip("\r\n "),
        "pub_date": release["published_at"],
        "platforms": {}
        }
    for asset in release.get("assets", []):
        for for_platforms, extension in PLATFORMS:
            if asset["name"].endswith(extension):
                for platform in for_platforms:
                    release_response["platforms"][platform] = {**release_response["platforms"].get(platform, {}), "url": asset["browser_download_url"]}
                    release_response["platforms"][platform] = {**release_response["platforms"].get(platform, {}), "signature": ""}
            elif asset["name"].endswith(f"{extension}.sig"):
                try:
                    sig = requests.get(asset["browser_download_url"]).text
                except requests.RequestException:
                    sig = ""
                for platform in for_platforms:
                    release_response["platforms"][platform] = {**release_response["platforms"].get(platform, {}), "signature": sig}
    return release_response

class UpdateInfo(Resource):
    def get(self, platform: str, current_version: str):
        latest_release = get_latest_gh_release()
        if not latest_release:
            return "", 204
        try:
            # version checks
            latest_version = latest_release["version"]
            latest_maj, latest_min, latest_patch = latest_version.lstrip("v").split(".")
            cur_maj, cur_min, cur_patch = current_version.lstrip("v").split(".")
            if cur_maj == latest_maj and cur_min == latest_min and cur_patch == latest_patch:
                raise ValueError
        except ValueError:
            return "", 204
        return latest_release

api.add_resource(UpdateInfo, "/<platform>/<current_version>")

if __name__ == "__main__":
    app.run(host="0.0.0.0", port=5000, debug=True)