[formatter] add 'q' & 'Q' conversions - URL-en/decode values

docs/formatting.md

@@ -189,6 +189,18 @@ Conversion specifiers allow to *convert* the value to a different form or type.
     <td><code>{created!D}</code></td>
     <td><code>2010-01-01 00:00:00</code></td>
 </tr>
+<tr>
+    <td align="center"><code>q</code></td>
+    <td><a href="https://docs.python.org/3/library/urllib.parse.html#urllib.parse.quote">URL-encode</a> a value</td>
+    <td><code>{jpn!q}</code></td>
+    <td><code>%E6%A3%AE</code></td>
+</tr>
+<tr>
+    <td align="center"><code>Q</code></td>
+    <td><a href="https://docs.python.org/3/library/urllib.parse.html#urllib.parse.unquote">URL-decode</a> a value</td>
+    <td><code>{jpn_url!Q}</code></td>
+    <td><code>森</code></td>
+</tr>
 <tr>
     <td align="center"><code>U</code></td>
     <td>Convert HTML entities</td>

gallery_dl/formatter.py

@@ -606,6 +606,8 @@ _CONVERSIONS = {
     "T": dt.to_ts_string,
     "d": dt.parse_ts,
     "D": dt.convert,
+    "q": text.quote,
+    "Q": text.unquote,
     "U": text.unescape,
     "H": lambda s: text.unescape(text.remove_html(s)),
     "g": text.slugify,

test/test_formatter.py

@@ -32,6 +32,7 @@ class TestFormatter(unittest.TestCase):
         "a": "hElLo wOrLd",
         "b": "äöü",
         "j": "げんそうきょう",
+        "J": "%E3%81%92%E3%82%93%E3%81%9D",
         "d": {"a": "foo", "b": 0, "c": None},
         "i": 2,
         "l": ["a", "b", "c"],
@@ -109,9 +110,13 @@ class TestFormatter(unittest.TestCase):
         self._run_test("{i_str!i}", 12345)
         self._run_test("{i_str!f}", 12345.0)
         self._run_test("{f_str!f}", 12.45)
+        self._run_test("{j!q}", "%E3%81%92%E3%82%93%E3%81%9D"
+                                "%E3%81%86%E3%81%8D%E3%82%87%E3%81%86")
+        self._run_test("{J!Q}", "げんそ")
 
+        # undefined conversion
         with self.assertRaises(KeyError):
-            self._run_test("{a!q}", "hello world")
+            self._run_test("{a!z}", "hello world")
 
     def test_optional(self):
         self._run_test("{name}{title1}", "NameTitle")