Downloads style/class files necessary to compile a LaTeX paper.

download-latex-files.py

#!/usr/bin/env python3

"""Downloads style/class files necessary to compile a LaTeX paper."""

import sys
import os
from os.path import join as pjoin
import argparse
from urllib.request import urlopen
from zipfile import ZipFile

CONFIGS = {
    'lipics': {
        'version': '2021.1.2',
        'zip_url': 'https://submission.dagstuhl.de/styles/download-tag/lipics/v2021.1.2/authors/zip',  # noqa
        'zip_fname': 'authors-lipics-v2021.zip',
        'files': {
            'lipics-v2021.cls': None,
            'lipics-logo-bw.pdf': None,
            'cc-by.pdf': None,
            'orcid.pdf': None,
        },
    },
    'sn-jnl': {
        'zip_url': 'https://media.springernature.com/full/springer-cms/rest/v1/content/18782940/data/Download+the+journal+article+template+package',  # noqa
        'zip_fname': 'sn-article-template.zip',
        'files': {
            'sn-article-template/sn-jnl.cls': 'sn-jnl.cls',
            'sn-article-template/bst/sn-mathphys.bst': 'sn-mathphys.bst',
        },
    },
}


def preprocess_configs():
    for config in CONFIGS.values():
        files_dict = config['files']
        for k, v in files_dict.items():
            if v is None:
                files_dict[k] = k


preprocess_configs()


def check_and_download(fpath, url):
    if os.path.exists(fpath):
        print(fpath, 'found', file=sys.stderr)
    else:
        print('downloading', url, file=sys.stderr)
        with urlopen(url) as fp:
            data = fp.read()
        with open(fpath, 'wb') as fp:
            fp.write(data)


def put_files(config, out_dir):
    out_dir = out_dir or ''
    found = True
    for fname in config['files'].values():
        if not os.path.exists(pjoin(out_dir, fname)):
            found = False
            print(pjoin(out_dir, fname), 'not found; retrieval/extraction needed', file=sys.stderr)
            break
    if found:
        print('all files found', file=sys.stderr)
        return

    zip_fpath = pjoin(out_dir, config['zip_fname'])
    check_and_download(zip_fpath, config['zip_url'])
    with ZipFile(zip_fpath) as zfp:
        for zfname, ufname in config['files'].items():
            with zfp.open(zfname, 'r') as fp:
                data = fp.read()
            with open(pjoin(out_dir, ufname), 'wb') as fp:
                fp.write(data)


def main():
    parser = argparse.ArgumentParser(description=__doc__)
    parser.add_argument('source', choices=CONFIGS.keys())
    parser.add_argument('-o', help="output directory (default: cwd)")
    args = parser.parse_args()
    put_files(CONFIGS[args.source], args.o)


if __name__ == '__main__':
    main()

Usually, external sources like LIPIcs and SpringerNature offer a zip file for download. This zip file contains the style/class files that you need, but you'd need to figure out where to place these files, and the zip file also contains other files that are not needed for compilation but clutter your working directory. Also, if you work on multiple computers, you'd need to find the URLs to the zip files and perform all these steps again. This script works around these problems by automating the process of downloading the zip file, extracting only the files that are necessary, and placing them at the right path in your working directory.

Place (or symlink) this file in the directory containing your LaTeX source files. Run this file with a single command-line argument specifying the external source. Run this file with --help for more info about command-line use.