Allow users to specify encoding in each config files (#4357)

Authored by: Lesmiscore

README.md

@@ -1161,6 +1161,15 @@ Note that options in configuration file are just the same options aka switches u
 
 You can use `--ignore-config` if you want to disable all configuration files for a particular yt-dlp run. If `--ignore-config` is found inside any configuration file, no further configuration will be loaded. For example, having the option in the portable configuration file prevents loading of home, user, and system configurations. Additionally, (for backward compatibility) if `--ignore-config` is found inside the system configuration file, the user configuration is not loaded.
 
+### Specifying encoding of config files
+
+By default, config files are read in the encoding from system locale.
+If you saved your config file in a different encoding than that, you may write `# coding: ENCODING` to the beginning of the file. (e.g. `# coding: shift-jis`)
+
+There must not be any characters before that, including spaces.
+
+If you have BOM enabled, it will be used instead.
+
 ### Authentication with `.netrc` file
 
 You may also want to configure automatic credentials storage for extractors that support authentication (by providing login and password with `--username` and `--password`) in order not to pass credentials as command line arguments on every yt-dlp execution and prevent tracking plain text passwords in the shell command history. You can achieve this using a [`.netrc` file](https://stackoverflow.com/tags/.netrc/info) on a per extractor basis. For that you will need to create a `.netrc` file in `--netrc-location` and restrict permissions to read/write by only you:

test/test_utils.py

@@ -39,6 +39,7 @@ from yt_dlp.utils import (
     datetime_from_str,
     detect_exe_version,
     determine_ext,
+    determine_file_encoding,
     dfxp2srt,
     dict_get,
     encode_base_n,
@@ -1822,6 +1823,33 @@ Line 1
             with contextlib.suppress(OSError):
                 os.remove(FILE)
 
+    def test_determine_file_encoding(self):
+        self.assertEqual(determine_file_encoding(b''), (None, 0))
+        self.assertEqual(determine_file_encoding(b'--verbose -x --audio-format mkv\n'), (None, 0))
+
+        self.assertEqual(determine_file_encoding(b'\xef\xbb\xbf'), ('utf-8', 3))
+        self.assertEqual(determine_file_encoding(b'\x00\x00\xfe\xff'), ('utf-32-be', 4))
+        self.assertEqual(determine_file_encoding(b'\xff\xfe'), ('utf-16-le', 2))
+
+        self.assertEqual(determine_file_encoding(b'# -*- coding: cp932 -*-'), ('cp932', 0))
+        self.assertEqual(determine_file_encoding(b'# -*- coding: cp932 -*-\n'), ('cp932', 0))
+        self.assertEqual(determine_file_encoding(b'# -*- coding: cp932 -*-\r\n'), ('cp932', 0))
+
+        self.assertEqual(determine_file_encoding(b'# coding: utf-8\n--verbose'), ('utf-8', 0))
+        self.assertEqual(determine_file_encoding(b'# coding: someencodinghere-12345\n--verbose'), ('someencodinghere-12345', 0))
+
+        self.assertEqual(determine_file_encoding(b'# vi: set fileencoding=cp932'), ('cp932', 0))
+        self.assertEqual(determine_file_encoding(b'# vi: set fileencoding=cp932\n'), ('cp932', 0))
+        self.assertEqual(determine_file_encoding(b'# vi: set fileencoding=cp932\r\n'), ('cp932', 0))
+        self.assertEqual(determine_file_encoding(b'# vi: set fileencoding=cp932,euc-jp\r\n'), ('cp932', 0))
+
+        self.assertEqual(determine_file_encoding(
+            b'\0\0\0#\0\0\0 \0\0\0c\0\0\0o\0\0\0d\0\0\0i\0\0\0n\0\0\0g\0\0\0:\0\0\0 \0\0\0u\0\0\0t\0\0\0f\0\0\0-\0\0\x003\0\0\x002\0\0\0-\0\0\0b\0\0\0e'),
+            ('utf-32-be', 0))
+        self.assertEqual(determine_file_encoding(
+            b'#\0 \0c\0o\0d\0i\0n\0g\0:\0 \0u\0t\0f\0-\x001\x006\0-\0l\0e\0'),
+            ('utf-16-le', 0))
+
 
 if __name__ == '__main__':
     unittest.main()

yt_dlp/utils.py

@@ -3485,9 +3485,6 @@ def age_restricted(content_limit, age_limit):
     return age_limit < content_limit
 
 
-def is_html(first_bytes):
-    """ Detect whether a file contains HTML by examining its first bytes. """
-
 BOMS = [
     (b'\xef\xbb\xbf', 'utf-8'),
     (b'\x00\x00\xfe\xff', 'utf-32-be'),
@@ -3495,6 +3492,11 @@ def is_html(first_bytes):
     (b'\xff\xfe', 'utf-16-le'),
     (b'\xfe\xff', 'utf-16-be'),
 ]
+""" List of known byte-order-marks (BOM) """
+
+
+def is_html(first_bytes):
+    """ Detect whether a file contains HTML by examining its first bytes. """
 
     encoding = 'utf-8'
     for bom, enc in BOMS:
@@ -5394,6 +5396,41 @@ def read_stdin(what):
     return sys.stdin
 
 
+def determine_file_encoding(data):
+    """
+    From the first 512 bytes of a given file,
+    it tries to detect the encoding to be used to read as text.
+
+    @returns (encoding, bytes to skip)
+    """
+
+    for bom, enc in BOMS:
+        # matching BOM beats any declaration
+        # BOMs are skipped to prevent any errors
+        if data.startswith(bom):
+            return enc, len(bom)
+
+    # strip off all null bytes to match even when UTF-16 or UTF-32 is used
+    # endians don't matter
+    data = data.replace(b'\0', b'')
+
+    PREAMBLES = [
+        # "# -*- coding: utf-8 -*-"
+        # "# coding: utf-8"
+        rb'(?m)^#(?:\s+-\*-)?\s*coding\s*:\s*(?P<encoding>\S+)(?:\s+-\*-)?\s*$',
+        # "# vi: set fileencoding=utf-8"
+        rb'^#\s+vi\s*:\s+set\s+fileencoding=(?P<encoding>[^\s,]+)'
+    ]
+    for pb in PREAMBLES:
+        mobj = re.match(pb, data)
+        if not mobj:
+            continue
+        # preambles aren't skipped since they're just ignored when reading as config
+        return mobj.group('encoding').decode(), 0
+
+    return None, 0
+
+
 class Config:
     own_args = None
     parsed_args = None
@@ -5445,12 +5482,17 @@ class Config:
     @staticmethod
     def read_file(filename, default=[]):
         try:
-            optionf = open(filename)
+            optionf = open(filename, 'rb')
         except OSError:
             return default  # silently skip if file is not present
+        try:
+            enc, skip = determine_file_encoding(optionf.read(512))
+            optionf.seek(skip, io.SEEK_SET)
+        except OSError:
+            enc = None  # silently skip read errors
         try:
             # FIXME: https://github.com/ytdl-org/youtube-dl/commit/dfe5fa49aed02cf36ba9f743b11b0903554b5e56
-            contents = optionf.read()
+            contents = optionf.read().decode(enc or preferredencoding())
             res = shlex.split(contents, comments=True)
         except Exception as err:
             raise ValueError(f'Unable to parse "{filename}": {err}')