A program that launches a dmenu choice of index terms to open python docs; or lets you search for a term; works with multiple versions

search-py-docs.py

#!/usr/bin/env python3.6

import re
from subprocess import run, PIPE
from pathlib import Path
import requests
import zipfile
import io
import pickle
import urllib

def searches(pattern, it):
    for x in it:
        match = re.search(pattern, x)
        if match:
            yield match.groups()

WORKING_DIR = Path('~/.pydocs').expanduser()
WORKING_DIR.mkdir(exist_ok=True)

dir_version = lambda version: WORKING_DIR.joinpath(f'python-{version}-docs-html')
url_version = lambda version, rest: 'file://{}/{}'.format(dir_version(version), rest)

def download_docs(version):
    url = f'https://docs.python.org/ftp/python/doc/{version}/python-{version}-docs-html.zip'
    r = requests.get(url)

    with io.BytesIO(r.content) as bh:
        with zipfile.ZipFile(bh) as zh:
            zh.extractall(WORKING_DIR)

def ensure_docs(version):
    if not dir_version(version).exists():
        download_docs(version)

def create_index(version):
    with open(dir_version(version).joinpath('genindex-all.html')) as fh:
        return {name: url for url, name in searches(r'<dt><a href="([^"]+)">(\w+)', fh)}

def ensure_index(version):
    fp = dir_version(f'index-{version}.pkl')
    if not fp.exists():
        index = create_index(version)
        with open(fp, 'wb') as fh:
            pickle.dump(index, fh)
        return index

    with open(fp, 'rb') as fh:
        return pickle.load(fh)

def launch_chrome(url):
    run(['google-chrome', f'--app={url}'])

def dmenu_choice(choices):
    return run(['dmenu'], input='\n'.join(choices), universal_newlines=True, check=True, stdout=PIPE).stdout.strip()

def go(version):
    ensure_docs(version)
    index = ensure_index(version)
    choice = dmenu_choice(index.keys())
    if choice in index:
        launch_chrome(url_version(version, index[choice]))

def search(version):
    ensure_docs(version)
    term = urllib.parse.quote(dmenu_choice([]))
    launch_chrome(url_version(version, f'search.html?q={term}'))

if __name__ == '__main__':
    import argparse
    parser = argparse.ArgumentParser()
    parser.add_argument('--version', default='3.6.2')
    parser.add_argument('--search', default=False, action='store_true')
    args = parser.parse_args()

    if args.search:
        search(args.version)
    else:
        go(args.version)