r"""Command-line tool to validate and pretty-print JSON
Usage::
$ echo '{"json":"obj"}' | python -m json.tool
{
"json": "obj"
}
$ echo '{ 1.2:3.4}' | python -m json.tool
Expecting property name enclosed in double quotes: line 1 column 3 (char 2)
"""
import argparse
import json
import sys
from pathlib import Path
def main():
prog = 'python -m json.tool'
description = ('A simple command line interface for json module '
'to validate and pretty-print JSON objects.')
parser = argparse.ArgumentParser(prog=prog, description=description)
parser.add_argument('infile', nargs='?',
type=argparse.FileType(encoding="utf-8"),
help='a JSON file to be validated or pretty-printed',
default=sys.stdin)
parser.add_argument('outfile', nargs='?',
type=Path,
help='write the output of infile to outfile',
default=None)
parser.add_argument('--sort-keys', action='store_true', default=False,
help='sort the output of dictionaries alphabetically by key')
parser.add_argument('--no-ensure-ascii', dest='ensure_ascii', action='store_false',
help='disable escaping of non-ASCII characters')
parser.add_argument('--json-lines', action='store_true', default=False,
help='parse input using the JSON Lines format. '
'Use with --no-indent or --compact to produce valid JSON Lines output.')
group = parser.add_mutually_exclusive_group()
group.add_argument('--indent', default=4, type=int,
help='separate items with newlines and use this number '
'of spaces for indentation')
group.add_argument('--tab', action='store_const', dest='indent',
const='\t', help='separate items with newlines and use '
'tabs for indentation')
group.add_argument('--no-indent', action='store_const', dest='indent',
const=None,
help='separate items with spaces rather than newlines')
group.add_argument('--compact', action='store_true',
help='suppress all whitespace separation (most compact)')
options = parser.parse_args()
dump_args = {
'sort_keys': options.sort_keys,
'indent': options.indent,
'ensure_ascii': options.ensure_ascii,
}
if options.compact:
dump_args['indent'] = None
dump_args['separators'] = ',', ':'
with options.infile as infile:
try:
if options.json_lines:
objs = (json.loads(line) for line in infile)
else:
objs = (json.load(infile),)
if options.outfile is None:
out = sys.stdout
else:
out = options.outfile.open('w', encoding='utf-8')
with out as outfile:
for obj in objs:
json.dump(obj, outfile, **dump_args)
outfile.write('\n')
except ValueError as e:
raise SystemExit(e)
if __name__ == '__main__':
try:
main()
except BrokenPipeError as exc:
sys.exit(exc.errno)
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