Update blender beta

blender-update.py

#!/usr/bin/env python3

################################################################
# Updates blender to the latest version
#
# Usage: update-blender.py
#
# On execution will search for the latest version on the blender
# website, download it and extract it to the path defined by
# `extract_to`. Will also create a `blender` symlink for the
# folder.
#
# Tested only on linux, YMMV. 
################################################################

from bs4 import BeautifulSoup
import tarfile
from tempfile import NamedTemporaryFile
from pathlib import Path
import progressbar
import urllib.request, urllib.error, urllib.parse

################################################################
# Configuration
#
base_url = 'https://builder.blender.org/download/'
version = '2.80'
os = 'linux'
arch = 'x86_64'
extract_to = Path('~/opt').expanduser()
#
################################################################

class DownloadProgressBar():
    """
    Used to present a progressbar while downloading the file.
    """
    def __init__(self):
        self.pbar = None

    def __call__(self, block_num, block_size, total_size):
        if not self.pbar:
            self.pbar=progressbar.ProgressBar(maxval=total_size)
            self.pbar.start()

        downloaded = block_num * block_size
        if downloaded < total_size:
            self.pbar.update(downloaded)
        else:
            self.pbar.finish()


def update_blender():
    """
    The main execution point. Downloads and extracts the latests version.
    """
    conn = urllib.request.urlopen(base_url)
    html = conn.read()

    soup = BeautifulSoup(html, features='lxml')
    links = soup.find_all('a')

    for tag in links:
        link = tag.get('href', None)
        if link is not None and f'/download/blender-{version}' in link and os in link and arch in link:
            url = urllib.parse.urljoin(base_url, link)
            name = link.split('/')[-1]
            with NamedTemporaryFile(suffix=f'_{name}') as tempf:
                print(f'Downloading file from {url} to {tempf.name}')
                urllib.request.urlretrieve(url, tempf.name, DownloadProgressBar())
                with tarfile.open(tempf.name, 'r:*') as tar:
                    extract(tar)


def extract(tar):
    """
    Extracts the provided tar and creates a symlink to the extracted dir.
    """
    dirname = tar.getnames()[0].split('/')[0]
    target_dir = extract_to / dirname

    if target_dir.is_dir():
        print(f'{target_dir.name} already exists, not overwriting!')
        return

    tar.extractall(extract_to)

    target_symlink = extract_to / 'blender'
    if target_symlink.is_symlink():
        print(f'Removing existing symlink to {target_symlink.resolve().name}')
        target_symlink.unlink()

    if not target_symlink.exists():
        print(f'Linking to extracted directory {dirname}')
        target_symlink.symlink_to(target_dir)


if __name__ == '__main__':
    update_blender()