cpython/Lib/json/tool.py

82 lines
3.2 KiB
Python

"""Command-line tool to validate and pretty-print JSON
See `json.__main__` for a usage example (invocation as
`python -m json.tool` is supported for backwards compatibility).
"""
import argparse
import json
import sys
def main():
description = ('A simple command line interface for json module '
'to validate and pretty-print JSON objects.')
parser = argparse.ArgumentParser(description=description)
parser.add_argument('infile', nargs='?',
help='a JSON file to be validated or pretty-printed',
default='-')
parser.add_argument('outfile', nargs='?',
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'] = ',', ':'
try:
if options.infile == '-':
infile = sys.stdin
else:
infile = open(options.infile, encoding='utf-8')
try:
if options.json_lines:
objs = (json.loads(line) for line in infile)
else:
objs = (json.load(infile),)
finally:
if infile is not sys.stdin:
infile.close()
if options.outfile is None:
outfile = sys.stdout
else:
outfile = open(options.outfile, 'w', encoding='utf-8')
with 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:
raise SystemExit(exc.errno)