renders and prints a jinja2 template with optional json to STDOUT

j2html.py

#!/usr/bin/env python3
# http://ix.io/2ykn/py

# renders and prints a jinja2 template with optional json to STDOUT
# requires: python3, jinja2

# usage
# $ ./j2html /path/to/template
# $ ./j2html /path/to/template --json_data /path/to/json

from jinja2 import Environment, FileSystemLoader
from pathlib import Path
import argparse
import json

if __name__ == '__main__':
    parser = argparse.ArgumentParser()
    parser.add_argument('template',
                        help='jinja2 template to process',
                        type=argparse.FileType('r', encoding='UTF-8'))
    parser.add_argument('--json_path',
                        help='json file passed to template',
                        type=argparse.FileType('r', encoding='UTF-8'))
    args = parser.parse_args()

    # load and parse json if provided
    json_path = Path(args.json_path.name) if args.json_path else None
    data = json.loads(json_path.read_text()) if json_path else {}

    # load and render template
    template_path = Path(args.template.name)
    env = Environment(
        loader=FileSystemLoader("{}/".format(template_path.parent)))
    print(env.get_template(template_path.name).render(data))

    # close files, because ArgumentParser does not
    args.template.close()
    if args.json_path:
        args.json_path.close()