Allow entire infodict to be printed using `%()s`

Makes `--dump-json` redundant

README.md

@@ -919,7 +919,7 @@ The simplest usage of `-o` is not to set any template arguments when downloading
 It may however also contain special sequences that will be replaced when downloading each video. The special sequences may be formatted according to [python string formatting operations](https://docs.python.org/2/library/stdtypes.html#string-formatting). For example, `%(NAME)s` or `%(NAME)05d`. To clarify, that is a percent symbol followed by a name in parentheses, followed by formatting operations.
 
 The field names themselves (the part inside the parenthesis) can also have some special formatting:
-1. **Object traversal**: The dictionaries and lists available in metadata can be traversed by using a `.` (dot) separator. You can also do python slicing using `:`. Eg: `%(tags.0)s`, `%(subtitles.en.-1.ext)`, `%(id.3:7:-1)s`, `%(formats.:.format_id)s`. Note that all the fields that become available using this method are not listed below. Use `-j` to see such fields
+1. **Object traversal**: The dictionaries and lists available in metadata can be traversed by using a `.` (dot) separator. You can also do python slicing using `:`. Eg: `%(tags.0)s`, `%(subtitles.en.-1.ext)s`, `%(id.3:7:-1)s`, `%(formats.:.format_id)s`. `%()s` refers to the entire infodict. Note that all the fields that become available using this method are not listed below. Use `-j` to see such fields
 1. **Addition**: Addition and subtraction of numeric fields can be done using `+` and `-` respectively. Eg: `%(playlist_index+10)03d`, `%(n_entries+1-playlist_index)d`
 1. **Date/time Formatting**: Date/time fields can be formatted according to [strftime formatting](https://docs.python.org/3/library/datetime.html#strftime-and-strptime-format-codes) by specifying it separated from the field name using a `>`. Eg: `%(duration>%H-%M-%S)s`, `%(upload_date>%Y-%m-%d)s`, `%(epoch-3600>%H-%M-%S)s`
 1. **Default**: A default value can be specified for when the field is empty using a `|` seperator. This overrides `--output-na-template`. Eg: `%(uploader|Unknown)s`
@@ -1417,6 +1417,7 @@ While these options are redundant, they are still expected to be used due to the
     --get-thumbnail                  --print thumbnail
     -e, --get-title                  --print title
     -g, --get-url                    --print urls
+    -j, --dump-json                  --print "%()j"
 
 
 #### Not recommended

test/test_YoutubeDL.py

@@ -668,15 +668,13 @@ class TestYoutubeDL(unittest.TestCase):
             out = ydl.escape_outtmpl(outtmpl) % tmpl_dict
             fname = ydl.prepare_filename(info or self.outtmpl_info)
 
-            if callable(expected):
-                self.assertTrue(expected(out))
-                self.assertTrue(expected(fname))
-            elif isinstance(expected, str):
-                self.assertEqual(out, expected)
-                self.assertEqual(fname, expected)
+            if not isinstance(expected, (list, tuple)):
+                expected = (expected, expected)
+            for (name, got), expect in zip((('outtmpl', out), ('filename', fname)), expected):
+                if callable(expect):
+                    self.assertTrue(expect(got), f'Wrong {name} from {tmpl}')
                 else:
-                self.assertEqual(out, expected[0])
-                self.assertEqual(fname, expected[1])
+                    self.assertEqual(got, expect, f'Wrong {name} from {tmpl}')
 
         # Side-effects
         original_infodict = dict(self.outtmpl_info)
@@ -721,7 +719,16 @@ class TestYoutubeDL(unittest.TestCase):
         # Invalid templates
         self.assertTrue(isinstance(YoutubeDL.validate_outtmpl('%(title)'), ValueError))
         test('%(invalid@tmpl|def)s', 'none', outtmpl_na_placeholder='none')
-        test('%()s', 'NA')
+        test('%(..)s', 'NA')
+
+        # Entire info_dict
+        def expect_same_infodict(out):
+            got_dict = json.loads(out)
+            for info_field, expected in self.outtmpl_info.items():
+                self.assertEqual(got_dict.get(info_field), expected, info_field)
+            return True
+
+        test('%()j', (expect_same_infodict, str))
 
         # NA placeholder
         NA_TEST_OUTTMPL = '%(uploader_date)s-%(width)d-%(x|def)s-%(id)s.%(ext)s'

yt_dlp/YoutubeDL.py

@@ -917,7 +917,7 @@ class YoutubeDL(object):
         }
         # Field is of the form key1.key2...
         # where keys (except first) can be string, int or slice
-        FIELD_RE = r'\w+(?:\.(?:\w+|{num}|{num}?(?::{num}?){{1,2}}))*'.format(num=r'(?:-?\d+)')
+        FIELD_RE = r'\w*(?:\.(?:\w+|{num}|{num}?(?::{num}?){{1,2}}))*'.format(num=r'(?:-?\d+)')
         MATH_FIELD_RE = r'''{field}|{num}'''.format(field=FIELD_RE, num=r'-?\d+(?:.\d+)?')
         MATH_OPERATORS_RE = r'(?:%s)' % '|'.join(map(re.escape, MATH_FUNCTIONS.keys()))
         INTERNAL_FORMAT_RE = re.compile(r'''(?x)
@@ -928,12 +928,15 @@ class YoutubeDL(object):
             (?:\|(?P<default>.*?))?
             $'''.format(field=FIELD_RE, math_op=MATH_OPERATORS_RE, math_field=MATH_FIELD_RE))
 
-        get_key = lambda k: traverse_obj(
-            info_dict, k.split('.'), is_user_input=True, traverse_string=True)
+        def _traverse_infodict(k):
+            k = k.split('.')
+            if k[0] == '':
+                k.pop(0)
+            return traverse_obj(info_dict, k, is_user_input=True, traverse_string=True)
 
         def get_value(mdict):
             # Object traversal
-            value = get_key(mdict['fields'])
+            value = _traverse_infodict(mdict['fields'])
             # Negative
             if mdict['negate']:
                 value = float_or_none(value)
@@ -955,7 +958,7 @@ class YoutubeDL(object):
                     item, multiplier = (item[1:], -1) if item[0] == '-' else (item, 1)
                     offset = float_or_none(item)
                     if offset is None:
-                        offset = float_or_none(get_key(item))
+                        offset = float_or_none(_traverse_infodict(item))
                     try:
                         value = operator(value, multiplier * offset)
                     except (TypeError, ZeroDivisionError):
@@ -2378,6 +2381,8 @@ class YoutubeDL(object):
         elif 'url' in info_dict:
             info_dict['urls'] = info_dict['url'] + info_dict.get('play_path', '')
 
+        if self.params.get('forceprint') or self.params.get('forcejson'):
+            self.post_extract(info_dict)
         for tmpl in self.params.get('forceprint', []):
             if re.match(r'\w+$', tmpl):
                 tmpl = '%({})s'.format(tmpl)
@@ -2394,8 +2399,7 @@ class YoutubeDL(object):
             self.to_stdout(formatSeconds(info_dict['duration']))
         print_mandatory('format')
 
-        if self.params.get('forcejson', False):
-            self.post_extract(info_dict)
+        if self.params.get('forcejson'):
             self.to_stdout(json.dumps(self.sanitize_info(info_dict)))
 
     def dl(self, name, info, subtitle=False, test=False):