rupdater

rupdater is a super lightweight and dependency-free updater, that provide remote version parsing, downloading and getting hash sum of an update.

Installation

rupdater can be install from PyPi by running:

pip install rupdater

Usage

First of all, create new instance of Updater. It takes 2 arguments: current local version and URL of the remote version data file:

from rupdater import Updater
updater = Updater('1.0.0a0', 'https://example.com/remote_version.json', use_json=True)

Now you can check for an update by calling the check() method:

if updater.check():
    print('Update found!')

After checking, you may want to download the update. This can be done with download() method, that returns a file-like object (byte-mode) of the downloaded update (it stores in a temp file). You should use it only with context manager.

with updater.download() as update_file, open('update.zip', 'w+b') as f:
    f.write(update_file.read())

This example will read the data from update_file and write it to the update.zip.

More complicated example with chunk-by-chunk reading/writing:

with updater.download() as update_file, open('update.zip', 'w+b') as f:
    for chunk in iter(lambda: update_file.read(1024 * 16), b''):
        f.write(chunk)

rupdater also has hash static method, that takes 2 required arguments and 1 optional: file-like object, hashing algorithm (as string) and chunk size, which is 1024 * 16 by default. This is the example of usage:

with updater.download() as update_file:
    hashes_match = Updater.hash_file(update_file, updater.hash_algo) == updater.hash

Warning! If you want to reuse the update file, you have to seek(0). Example:

with updater.download() as update_file, open('update.zip', 'w+b') as f:
    for chunk in iter(lambda: update_file.read(1024 * 16), b''):
        f.write(chunk)
    f.seek(0)
    assert Updater.hash_file(f, updater.hash_algo) == updater.hash

You can also parse version data again manually by calling get_version_data().

Portability

rupdater.py is absolutely independent of anything at the moment. Python Standard Library is the only requirement. So if you need, you can just copy this file and use it like a single module.

Exceptions handling

rupdater does not catch any errors, you have to do it yourself as prefer. In addition, rupdater may raise ValueError when incorrect input data was given (version data file does not formatted properly, unknown hashing algorithm etc).