gh-131952: Add color to the json CLI

Doc/whatsnew/3.14.rst

@@ -789,6 +789,12 @@ json
  See the :ref:`JSON command-line interface <json-commandline>` documentation.
  (Contributed by Trey Hunner in :gh:`122873`.)
 
+* By default, the output of the :ref:`JSON command-line interface <json-commandline>`
+ is highlighted in color. This can be controlled via the
+ :envvar:`PYTHON_COLORS` environment variable as well as the canonical
+ |NO_COLOR|_ and |FORCE_COLOR|_ environment variables. See also
+ :ref:`using-on-controlling-color`.
+ (Contributed by Tomas Roun in :gh:`131952`.)
 
 linecache
 ---------

Lib/json/tool.py

@@ -5,7 +5,40 @@
 """
 import argparse
 import json
+import re
 import sys
+from _colorize import ANSIColors, can_colorize
+
+
+# The string we are colorizing is valid JSON,
+# so we can use a looser but simpler regex to match
+# the various parts, most notably strings and numbers,
+# where the regex given by the spec is much more complex.
+_color_pattern = re.compile(r'''
+ (?P<key>"(\\.|[^"\\])*")(?=:) |
+ (?P<string>"(\\.|[^"\\])*") |
+ (?P<boolean>true|false) |
+ (?P<null>null)
+''', re.VERBOSE)
+
+
+_colors ={
+ 'key': ANSIColors.INTENSE_BLUE,
+ 'string': ANSIColors.BOLD_GREEN,
+ 'boolean': ANSIColors.BOLD_CYAN,
+ 'null': ANSIColors.BOLD_CYAN,
+}
+
+
+def _replace_match_callback(match):
+ for key, color in _colors.items():
+ if m := match.group(key):
+ return f"{color}{m}{ANSIColors.RESET}"
+ return match.group()
+
+
+def _colorize_json(json_str):
+ return re.sub(_color_pattern, _replace_match_callback, json_str)
 
 
 def main():
@@ -68,7 +101,11 @@ def main():
  outfile = open(options.outfile, 'w', encoding='utf-8')
  with outfile:
  for obj in objs:
- json.dump(obj, outfile, **dump_args)
+ if can_colorize(file=outfile):
+ json_str = json.dumps(obj, **dump_args)
+ outfile.write(_colorize_json(json_str))
+ else:
+ json.dump(obj, outfile, **dump_args)
  outfile.write('\n')
  except ValueError as e:
  raise SystemExit(e)

Lib/test/test_json/test_tool.py

@@ -6,7 +6,7 @@
 import subprocess
 
 from test import support
-from test.support import os_helper
+from test.support import force_not_colorized, os_helper
 from test.support.script_helper import assert_python_ok
 
 
@@ -87,6 +87,7 @@ class TestMain(unittest.TestCase):
  }
  """)
 
+ @force_not_colorized
  def test_stdin_stdout(self):
  args = sys.executable, '-m', self.module
  process = subprocess.run(args, input=self.data, capture_output=True, text=True, check=True)
@@ -102,7 +103,8 @@ def _create_infile(self, data=None):
 
  def test_infile_stdout(self):
  infile = self._create_infile()
- rc, out, err = assert_python_ok('-m', self.module, infile)
+ rc, out, err = assert_python_ok('-m', self.module, infile,
+ PYTHON_COLORS='0')
  self.assertEqual(rc, 0)
  self.assertEqual(out.splitlines(), self.expect.encode().splitlines())
  self.assertEqual(err, b'')
@@ -116,7 +118,8 @@ def test_non_ascii_infile(self):
  ''').encode()
 
  infile = self._create_infile(data)
- rc, out, err = assert_python_ok('-m', self.module, infile)
+ rc, out, err = assert_python_ok('-m', self.module, infile,
+ PYTHON_COLORS='0')
 
  self.assertEqual(rc, 0)
  self.assertEqual(out.splitlines(), expect.splitlines())
@@ -125,7 +128,8 @@ def test_non_ascii_infile(self):
  def test_infile_outfile(self):
  infile = self._create_infile()
  outfile = os_helper.TESTFN + '.out'
- rc, out, err = assert_python_ok('-m', self.module, infile, outfile)
+ rc, out, err = assert_python_ok('-m', self.module, infile, outfile,
+ PYTHON_COLORS='0')
  self.addCleanup(os.remove, outfile)
  with open(outfile, "r", encoding="utf-8") as fp:
  self.assertEqual(fp.read(), self.expect)
@@ -135,33 +139,38 @@ def test_infile_outfile(self):
 
  def test_writing_in_place(self):
  infile = self._create_infile()
- rc, out, err = assert_python_ok('-m', self.module, infile, infile)
+ rc, out, err = assert_python_ok('-m', self.module, infile, infile,
+ PYTHON_COLORS='0')
  with open(infile, "r", encoding="utf-8") as fp:
  self.assertEqual(fp.read(), self.expect)
  self.assertEqual(rc, 0)
  self.assertEqual(out, b'')
  self.assertEqual(err, b'')
 
+ @force_not_colorized
  def test_jsonlines(self):
  args = sys.executable, '-m', self.module, '--json-lines'
  process = subprocess.run(args, input=self.jsonlines_raw, capture_output=True, text=True, check=True)
  self.assertEqual(process.stdout, self.jsonlines_expect)
  self.assertEqual(process.stderr, '')
 
  def test_help_flag(self):
- rc, out, err = assert_python_ok('-m', self.module, '-h')
+ rc, out, err = assert_python_ok('-m', self.module, '-h',
+ PYTHON_COLORS='0')
  self.assertEqual(rc, 0)
  self.assertTrue(out.startswith(b'usage: '))
  self.assertEqual(err, b'')
 
  def test_sort_keys_flag(self):
  infile = self._create_infile()
- rc, out, err = assert_python_ok('-m', self.module, '--sort-keys', infile)
+ rc, out, err = assert_python_ok('-m', self.module, '--sort-keys', infile,
+ PYTHON_COLORS='0')
  self.assertEqual(rc, 0)
  self.assertEqual(out.splitlines(),
  self.expect_without_sort_keys.encode().splitlines())
  self.assertEqual(err, b'')
 
+ @force_not_colorized
  def test_indent(self):
  input_ = '[1, 2]'
  expect = textwrap.dedent('''\
@@ -175,6 +184,7 @@ def test_indent(self):
  self.assertEqual(process.stdout, expect)
  self.assertEqual(process.stderr, '')
 
+ @force_not_colorized
  def test_no_indent(self):
  input_ = '[1,\n2]'
  expect = '[1, 2]\n'
@@ -183,6 +193,7 @@ def test_no_indent(self):
  self.assertEqual(process.stdout, expect)
  self.assertEqual(process.stderr, '')
 
+ @force_not_colorized
  def test_tab(self):
  input_ = '[1, 2]'
  expect = '[\n\t1,\n\t2\n]\n'
@@ -191,6 +202,7 @@ def test_tab(self):
  self.assertEqual(process.stdout, expect)
  self.assertEqual(process.stderr, '')
 
+ @force_not_colorized
  def test_compact(self):
  input_ = '[ 1 ,\n 2]'
  expect = '[1,2]\n'
@@ -203,7 +215,8 @@ def test_no_ensure_ascii_flag(self):
  infile = self._create_infile('{"key":"💩"}')
  outfile = os_helper.TESTFN + '.out'
  self.addCleanup(os.remove, outfile)
- assert_python_ok('-m', self.module, '--no-ensure-ascii', infile, outfile)
+ assert_python_ok('-m', self.module, '--no-ensure-ascii', infile,
+ outfile, PYTHON_COLORS='0')
  with open(outfile, "rb") as f:
  lines = f.read().splitlines()
  # asserting utf-8 encoded output file
@@ -214,13 +227,14 @@ def test_ensure_ascii_default(self):
  infile = self._create_infile('{"key":"💩"}')
  outfile = os_helper.TESTFN + '.out'
  self.addCleanup(os.remove, outfile)
- assert_python_ok('-m', self.module, infile, outfile)
+ assert_python_ok('-m', self.module, infile, outfile, PYTHON_COLORS='0')
  with open(outfile, "rb") as f:
  lines = f.read().splitlines()
  # asserting an ascii encoded output file
  expected = [b'{', rb' "key": "\ud83d\udca9"', b"}"]
  self.assertEqual(lines, expected)
 
+ @force_not_colorized
  @unittest.skipIf(sys.platform =="win32", "The test is failed with ValueError on Windows")
  def test_broken_pipe_error(self):
  cmd = [sys.executable, '-m', self.module]
@@ -232,7 +246,73 @@ def test_broken_pipe_error(self):
  proc.communicate(b'"{}"')
  self.assertEqual(proc.returncode, errno.EPIPE)
 
+ def test_colors(self):
+ infile = os_helper.TESTFN
+ self.addCleanup(os.remove, infile)
+
+ cases = (
+ ('{}', b'{}'),
+ ('[]', b'[]'),
+ ('null', b'\x1b[1;36mnull\x1b[0m'),
+ ('true', b'\x1b[1;36mtrue\x1b[0m'),
+ ('false', b'\x1b[1;36mfalse\x1b[0m'),
+ ('NaN', b'NaN'),
+ ('Infinity', b'Infinity'),
+ ('-Infinity', b'-Infinity'),
+ ('"foo"', b'\x1b[1;32m"foo"\x1b[0m'),
+ (r'" \"foo\" "', b'\x1b[1;32m" \\"foo\\" "\x1b[0m'),
+ ('"α"', b'\x1b[1;32m"\\u03b1"\x1b[0m'),
+ ('123', b'123'),
+ ('-1.2345e+23', b'-1.2345e+23'),
+ (r'{"\\": ""}',
+ b'''\
+{
+ \x1b[94m"\\\\"\x1b[0m: \x1b[1;32m""\x1b[0m
+}'''),
+ (r'{"\\\\": ""}',
+ b'''\
+{
+ \x1b[94m"\\\\\\\\"\x1b[0m: \x1b[1;32m""\x1b[0m
+}'''),
+ ('''\
+{
+ "foo": "bar",
+ "baz": 1234,
+ "qux": [true, false, null],
+ "xyz": [NaN, -Infinity, Infinity]
+}''',
+ b'''\
+{
+ \x1b[94m"foo"\x1b[0m: \x1b[1;32m"bar"\x1b[0m,
+ \x1b[94m"baz"\x1b[0m: 1234,
+ \x1b[94m"qux"\x1b[0m: [
+ \x1b[1;36mtrue\x1b[0m,
+ \x1b[1;36mfalse\x1b[0m,
+ \x1b[1;36mnull\x1b[0m
+ ],
+ \x1b[94m"xyz"\x1b[0m: [
+ NaN,
+ -Infinity,
+ Infinity
+ ]
+}'''),
+ )
+
+ for input_, expected in cases:
+ with self.subTest(input=input_):
+ with open(infile, "w", encoding="utf-8") as fp:
+ fp.write(input_)
+ _, stdout, _ = assert_python_ok('-m', self.module, infile,
+ PYTHON_COLORS='1')
+ stdout = stdout.replace(b'\r\n', b'\n') # normalize line endings
+ stdout = stdout.strip()
+ self.assertEqual(stdout, expected)
+
 
 @support.requires_subprocess()
 class TestTool(TestMain):
  module = 'json.tool'
+
+
+if __name__ == "__main__":
+ unittest.main()

Misc/NEWS.d/next/Library/2025-04-05-16-05-34.gh-issue-131952.HX6gCX.rst

@@ -0,0 +1 @@
+Add color output to the :program:`json` CLI. Patch by Tomas Roun.