[devscripts] Add a hack to convert command-line options to API options

diff --git a/devscripts/cli_to_api.py b/devscripts/cli_to_api.py
new file mode 100755 (executable)
index 0000000..2f4d6a4
--- /dev/null
+++ b/devscripts/cli_to_api.py
@@ -0,0 +1,64 @@
+#!/usr/bin/env python
+# coding: utf-8
+
+from __future__ import unicode_literals
+
+"""
+This script displays the API parameters corresponding to a yt-dl command line
+
+Example:
+$ ./cli_to_api.py -f best
+{u'format': 'best'}
+$
+"""
+
+# Allow direct execution
+import os
+import sys
+sys.path.insert(0, os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
+
+import youtube_dl
+from types import MethodType
+
+
+def cli_to_api(*opts):
+    YDL = youtube_dl.YoutubeDL
+
+    # to extract the parsed options, break out of YoutubeDL instantiation
+
+    # return options via this Exception
+    class ParseYTDLResult(Exception):
+        def __init__(self, result):
+            super(ParseYTDLResult, self).__init__('result')
+            self.opts = result
+
+    # replacement constructor that raises ParseYTDLResult
+    def ytdl_init(ydl, ydl_opts):
+        super(YDL, ydl).__init__(ydl_opts)
+        raise ParseYTDLResult(ydl_opts)
+
+    # patch in the constructor
+    YDL.__init__ = MethodType(ytdl_init, YDL)
+
+    # core parser
+    def parsed_options(argv):
+        try:
+            youtube_dl._real_main(list(argv))
+        except ParseYTDLResult as result:
+            return result.opts
+
+    # from https://github.com/yt-dlp/yt-dlp/issues/5859#issuecomment-1363938900
+    default = parsed_options([])
+    diff = dict((k, v) for k, v in parsed_options(opts).items() if default[k] != v)
+    if 'postprocessors' in diff:
+        diff['postprocessors'] = [pp for pp in diff['postprocessors'] if pp not in default['postprocessors']]
+    return diff
+
+
+def main():
+    from pprint import pprint
+    pprint(cli_to_api(*sys.argv))
+
+
+if __name__ == '__main__':
+    main()