add conversion to remove invisible char then strip

gallery_dl/formatter.py

@@ -407,6 +407,7 @@ _CONVERSIONS = {
     "s": str,
     "r": repr,
     "a": ascii,
+    "i": util.remove_invisible_chars_strip,
 }
 _FORMAT_SPECIFIERS = {
     "?": _parse_optional,

gallery_dl/util.py

@@ -21,6 +21,7 @@ import datetime
 import functools
 import itertools
 import subprocess
+import unicodedata
 import urllib.parse
 from http.cookiejar import Cookie
 from email.utils import mktime_tz, parsedate_tz
@@ -209,6 +210,10 @@ def to_string(value):
             return ", ".join(map(str, value))
     return str(value)
 
+def remove_invisible_chars_strip(text):
+    """Remove all invisible characters from 'text' then strip"""
+    return "".join(c for c in text if unicodedata.category(c)[0] != "C").strip()
+
 
 def datetime_to_timestamp(dt):
     """Convert naive UTC datetime to timestamp"""