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1r"""Command-line tool to validate and pretty-print JSON
2
3Usage::
4
5    $ echo '{"json":"obj"}' | python -m json.tool
6    {
7        "json": "obj"
8    }
9    $ echo '{ 1.2:3.4}' | python -m json.tool
10    Expecting property name enclosed in double quotes: line 1 column 3 (char 2)
11
12"""
13import argparse
14import json
15import sys
16from pathlib import Path
17
18
19def main():
20    prog = 'python -m json.tool'
21    description = ('A simple command line interface for json module '
22                   'to validate and pretty-print JSON objects.')
23    parser = argparse.ArgumentParser(prog=prog, description=description)
24    parser.add_argument('infile', nargs='?',
25                        type=argparse.FileType(encoding="utf-8"),
26                        help='a JSON file to be validated or pretty-printed',
27                        default=sys.stdin)
28    parser.add_argument('outfile', nargs='?',
29                        type=Path,
30                        help='write the output of infile to outfile',
31                        default=None)
32    parser.add_argument('--sort-keys', action='store_true', default=False,
33                        help='sort the output of dictionaries alphabetically by key')
34    parser.add_argument('--no-ensure-ascii', dest='ensure_ascii', action='store_false',
35                        help='disable escaping of non-ASCII characters')
36    parser.add_argument('--json-lines', action='store_true', default=False,
37                        help='parse input using the JSON Lines format. '
38                        'Use with --no-indent or --compact to produce valid JSON Lines output.')
39    group = parser.add_mutually_exclusive_group()
40    group.add_argument('--indent', default=4, type=int,
41                       help='separate items with newlines and use this number '
42                       'of spaces for indentation')
43    group.add_argument('--tab', action='store_const', dest='indent',
44                       const='\t', help='separate items with newlines and use '
45                       'tabs for indentation')
46    group.add_argument('--no-indent', action='store_const', dest='indent',
47                       const=None,
48                       help='separate items with spaces rather than newlines')
49    group.add_argument('--compact', action='store_true',
50                       help='suppress all whitespace separation (most compact)')
51    options = parser.parse_args()
52
53    dump_args = {
54        'sort_keys': options.sort_keys,
55        'indent': options.indent,
56        'ensure_ascii': options.ensure_ascii,
57    }
58    if options.compact:
59        dump_args['indent'] = None
60        dump_args['separators'] = ',', ':'
61
62    with options.infile as infile:
63        try:
64            if options.json_lines:
65                objs = (json.loads(line) for line in infile)
66            else:
67                objs = (json.load(infile),)
68
69            if options.outfile is None:
70                out = sys.stdout
71            else:
72                out = options.outfile.open('w', encoding='utf-8')
73            with out as outfile:
74                for obj in objs:
75                    json.dump(obj, outfile, **dump_args)
76                    outfile.write('\n')
77        except ValueError as e:
78            raise SystemExit(e)
79
80
81if __name__ == '__main__':
82    try:
83        main()
84    except BrokenPipeError as exc:
85        sys.exit(exc.errno)
86