use click instead of argparse to build command line tools

Author: Linusp

inoreader/main.py

@@ -6,12 +6,12 @@
 import sys
 import json
 import codecs
-import argparse
 from datetime import datetime
 from collections import defaultdict
 from configparser import ConfigParser
 
 import yaml
+import click
 from inoreader import InoreaderClient
 from inoreader.filter import get_filter
 
@@ -67,26 +67,14 @@ def get_client():
     return client
 
 
-class SubcommandHelpFormatter(argparse.RawDescriptionHelpFormatter):
-    def _format_action(self, action):
-        parts = super(argparse.RawDescriptionHelpFormatter, self)._format_action(action)
-        if action.nargs == argparse.PARSER:
-            parts = "\n".join(parts.split("\n")[1:])
-        return parts
-
-
-class CmdParser(argparse.ArgumentParser):
-    def error(self, message):
-        sys.stderr.write('error: %s\n\n' % message)
-        self.print_help()
-        sys.exit(1)
-
-
-def add_login_parser(subparsers):
-    subparsers.add_parser('login', help="Login to Inoreader")
+@click.group(context_settings=dict(help_option_names=['-h', '--help']))
+def main():
+    pass
 
 
+@main.command()
 def login():
+    """Login to your inoreader account"""
     client = InoreaderClient(None, None)
 
     username = input("EMAIL: ").strip()
@@ -112,43 +100,35 @@ def login():
         sys.exit(1)
 
 
-def add_folders_list_parser(subparsers):
-    subparsers.add_parser('list-folders', help="List all folders")
-
-
+@main.command("list-folders")
 def list_folders():
+    """List all folders"""
     client = get_client()
     res = client.get_folders()
     print("unread\tfolder")
     for item in res:
         print("{}\t{}".format(item['unread_count'], item['name']))
 
 
-def add_tags_list_parser(subparsers):
-    subparsers.add_parser('list-tags', help="List all tags")
-
-
+@main.command("list-tags")
 def list_tags():
+    """List all tags"""
     client = get_client()
     res = client.get_tags()
     for item in res:
         print("{}\t{}".format(item['unread_count'], item['name']))
 
 
-def add_unread_fetch_parser(subparsers):
-    parser = subparsers.add_parser('fetch-unread', help='Fetch unread articles')
-    parser.add_argument("-f", "--folder", required=True, help='Folder which articles belong to')
-    parser.add_argument("-t", "--tags", help="Tag(s) for filtering, seprate with comma")
-    parser.add_argument("-o", "--outfile", required=True, help="Filename to save articles")
-    parser.add_argument(
-        "--out-format",
-        choices=['json', 'csv', 'plain', 'markdown', 'org-mode'],
-        default='json',
-        help='Format of output file, default: json'
-    )
-
-
+@main.command("fetch-unread")
+@click.option("-f", "--folder", required=True, help='Folder which articles belong to')
+@click.option("-t", "--tags", help="Tag(s) for filtering, seprate with comma")
+@click.option("-o", "--outfile", required=True, help="Filename to save articles")
+@click.option("--out-format",
+              type=click.Choice(['json', 'csv', 'plain', 'markdown', 'org-mode']),
+              default='json',
+              help='Format of output file, default: json')
 def fetch_unread(folder, tags, outfile, out_format):
+    """Fetch unread articles"""
     client = get_client()
 
     tag_list = [] if not tags else tags.split(',')
@@ -179,11 +159,6 @@ def fetch_unread(folder, tags, outfile, out_format):
     fout.close()
 
 
-def add_filter_parser(subparsers):
-    parser = subparsers.add_parser('filter', help='Select articles and do something')
-    parser.add_argument("-r", "--rules", required=True, help='YAML file with your rules')
-
-
 def apply_action(articles, client, action, tags):
     if action == 'tag':
         for tag in tags.split(','):
@@ -209,7 +184,10 @@ def apply_action(articles, client, action, tags):
             print("Starred article: {}".format(article.title))
 
 
+@main.command("filter")
+@click.option("-r", "--rules-file", required=True, help='YAML file with your rules')
 def filter_articles(rules_file):
+    """Select articles and do something"""
     client = get_client()
     filters = []
     for rule in yaml.load(open(rules_file)):
@@ -275,32 +253,5 @@ def filter_articles(rules_file):
                 apply_action([article], client, 'tag', action['tags'])
 
 
-def main():
-    parser = CmdParser(
-        usage="inoreader [-h] <command> ...",
-        formatter_class=SubcommandHelpFormatter
-    )
-    subparsers = parser.add_subparsers(title="commands", dest='command')
-    subparsers.required = True
-
-    add_login_parser(subparsers)
-    add_folders_list_parser(subparsers)
-    add_tags_list_parser(subparsers)
-    add_unread_fetch_parser(subparsers)
-    add_filter_parser(subparsers)
-
-    args = parser.parse_args()
-    if args.command == 'login':
-        login()
-    elif args.command == 'list-folders':
-        list_folders()
-    elif args.command == 'list-tags':
-        list_tags()
-    elif args.command == 'fetch-unread':
-        fetch_unread(args.folder, args.tags, args.outfile, args.out_format)
-    elif args.command == 'filter':
-        filter_articles(args.rules)
-
-
 if __name__ == '__main__':
     main()