bpo-29636: improve CLI of json.tool

Doc/library/json.rst

@@ -717,6 +717,16 @@ Command line options
 
    .. versionadded:: 3.5
 
+.. cmdoption:: --indent
+
+   Specify a string or integer to use as the indent, see :func:`json.dumps` for more information.
+
+   .. versionadded:: 3.8
+
+.. cmdoption:: --no-ensure-ascii
+
+   Disable escaping of non-ascii characters, see :func:`json.dumps` for more information.
+
 .. cmdoption:: --json-lines
 
    Parse every input line as separate JSON object.

Lib/json/tool.py

@@ -24,6 +24,10 @@ def main():
                         help='a JSON file to be validated or pretty-printed')
     parser.add_argument('outfile', nargs='?', type=argparse.FileType('w'),
                         help='write the output of infile to outfile')
+    parser.add_argument('--indent', default=4,
+                        help='the indentation for pretty-print (int or str)')
+    parser.add_argument('--no-ensure-ascii', dest='ensure_ascii', action='store_false',
+                        help='disable escaping of non-ASCII characters')
     parser.add_argument('--sort-keys', action='store_true', default=False,
                         help='sort the output of dictionaries alphabetically by key')
     parser.add_argument('--json-lines', action='store_true', default=False,
@@ -33,6 +37,11 @@ def main():
     infile = options.infile or sys.stdin
     outfile = options.outfile or sys.stdout
     sort_keys = options.sort_keys
+    try:
+        indent = int(options.indent)
+    except ValueError:
+        # it is also possible to specify a string here
+        indent = options.indent
     json_lines = options.json_lines
     with infile, outfile:
         try:
@@ -41,7 +50,8 @@ def main():
             else:
                 objs = (json.load(infile), )
             for obj in objs:
-                json.dump(obj, outfile, sort_keys=sort_keys, indent=4)
+                json.dump(obj, outfile, sort_keys=sort_keys, indent=indent,
+                          ensure_ascii=options.ensure_ascii)
                 outfile.write('\n')
         except ValueError as e:
             raise SystemExit(e)

Lib/test/test_json/test_tool.py

@@ -134,3 +134,33 @@ def test_sort_keys_flag(self):
         self.assertEqual(out.splitlines(),
                          self.expect_without_sort_keys.encode().splitlines())
         self.assertEqual(err, b'')
+
+    def test_custom_indent_int(self):
+        infile = support.TESTFN
+        with open(infile, "w") as f:
+            self.addCleanup(os.remove, infile)
+            f.write('{"key":"val"}')
+        rc, out, err = assert_python_ok('-m', 'json.tool', '--indent=3', infile)
+        self.assertEqual(out.splitlines(),
+                         [b'{', b'   "key": "val"', b"}"])
+        self.assertEqual(err, b'')
+
+    def test_custom_indent_str(self):
+        infile = support.TESTFN
+        with open(infile, "w") as f:
+            self.addCleanup(os.remove, infile)
+            f.write('{"key":"val"}')
+        rc, out, err = assert_python_ok('-m', 'json.tool', '--indent', '\t', infile)
+        self.assertEqual(out.splitlines(),
+                         [b'{', b'\t"key": "val"', b"}"])
+        self.assertEqual(err, b'')
+
+    def test_non_ascii(self):
+        infile = support.TESTFN
+        with open(infile, "w", encoding='utf-8') as f:
+            self.addCleanup(os.remove, infile)
+            f.write('{"key":"💩"}')
+        rc, out, err = assert_python_ok('-m', 'json.tool', '--no-ensure-ascii', infile)
+        self.assertEqual(out.splitlines(),
+                         [b'{', b'    "key": "\xf0\x9f\x92\xa9"', b"}"])
+        self.assertEqual(err, b'')

Misc/NEWS.d/next/Library/2018-10-09-00-03-32.bpo-29636.UKAlMj.rst

@@ -0,0 +1,2 @@
+Added ability to pass through `indent` and `ensure_ascii` options in
+`json.tool` command-line interface.