Add --enable-file-urls (#5917)

Closes https://github.com/yt-dlp/yt-dlp/issues/3675

Authored by: coletdjnz

yt_dlp/YoutubeDL.py

@@ -318,6 +318,7 @@ class YoutubeDL:
                         If not provided and the key is encrypted, yt-dlp will ask interactively
     prefer_insecure:   Use HTTP instead of HTTPS to retrieve information.
                        (Only supported by some extractors)
+    enable_file_urls:  Enable file:// URLs. This is disabled by default for security reasons.
     http_headers:      A dictionary of custom headers to be used for all requests
     proxy:             URL of the proxy server to use
     geo_verification_proxy:  URL of the proxy to use for IP address verification
@@ -3875,9 +3876,12 @@ class YoutubeDL:
         # https://github.com/ytdl-org/youtube-dl/issues/8227)
         file_handler = urllib.request.FileHandler()
 
-        def file_open(*args, **kwargs):
-            raise urllib.error.URLError('file:// scheme is explicitly disabled in yt-dlp for security reasons')
-        file_handler.file_open = file_open
+        if not self.params.get('enable_file_urls'):
+            def file_open(*args, **kwargs):
+                raise urllib.error.URLError(
+                    'file:// URLs are explicitly disabled in yt-dlp for security reasons. '
+                    'Use --enable-file-urls to enable at your own risk.')
+            file_handler.file_open = file_open
 
         opener = urllib.request.build_opener(
             proxy_handler, https_handler, cookie_processor, ydlh, redirect_handler, data_handler, file_handler)