[ie/generic] Do not impersonate by default (fix edfd095b19) (#11336)

Closes #11335
Authored by: bashonly

README.md

@@ -1791,7 +1791,7 @@ #### generic
 * `key_query`: Passthrough the master m3u8 URL query to its HLS AES-128 decryption key URI if no value is provided, or else apply the query string given as `key_query=VALUE`. Note that this will have no effect if the key URI is provided via the `hls_key` extractor-arg. Does not apply to ffmpeg
 * `hls_key`: An HLS AES-128 key URI *or* key (as hex), and optionally the IV (as hex), in the form of `(URI|KEY)[,IV]`; e.g. `generic:hls_key=ABCDEF1234567980,0xFEDCBA0987654321`. Passing any of these values will force usage of the native HLS downloader and override the corresponding values found in the m3u8 playlist
 * `is_live`: Bypass live HLS detection and manually set `live_status` - a value of `false` will set `not_live`, any other value (or no value) will set `is_live`
-* `impersonate`: Target(s) to try and impersonate with the initial webpage request; e.g. `safari,chrome-110`. By default any available target will be used. Use `false` to disable impersonation
+* `impersonate`: Target(s) to try and impersonate with the initial webpage request; e.g. `generic:impersonate=safari,chrome-110`. Use `generic:impersonate` to impersonate any available target, and use `generic:impersonate=false` to disable impersonation (default)
 
 #### funimation
 * `language`: Audio languages to extract, e.g. `funimation:language=english,japanese`

yt_dlp/extractor/generic.py

@@ -8,6 +8,8 @@
 from .commonprotocols import RtmpIE
 from .youtube import YoutubeIE
 from ..compat import compat_etree_fromstring
+from ..cookies import LenientSimpleCookie
+from ..networking.exceptions import HTTPError
 from ..networking.impersonate import ImpersonateTarget
 from ..utils import (
     KNOWN_EXTENSIONS,
@@ -2374,10 +2376,9 @@ def _real_extract(self, url):
         else:
             video_id = self._generic_id(url)
 
-        # Try to impersonate a web-browser by default if possible
-        # Skip impersonation if not available to omit the warning
-        impersonate = self._configuration_arg('impersonate', [''])
-        if 'false' in impersonate or not self._downloader._impersonate_target_available(ImpersonateTarget()):
+        # Do not impersonate by default; see https://github.com/yt-dlp/yt-dlp/issues/11335
+        impersonate = self._configuration_arg('impersonate', ['false'])
+        if 'false' in impersonate:
             impersonate = None
 
         # Some webservers may serve compressed content of rather big size (e.g. gzipped flac)
@@ -2388,10 +2389,29 @@ def _real_extract(self, url):
         # to accept raw bytes and being able to download only a chunk.
         # It may probably better to solve this by checking Content-Type for application/octet-stream
         # after a HEAD request, but not sure if we can rely on this.
+        try:
             full_response = self._request_webpage(url, video_id, headers=filter_dict({
                 'Accept-Encoding': 'identity',
                 'Referer': smuggled_data.get('referer'),
             }), impersonate=impersonate)
+        except ExtractorError as e:
+            if not (isinstance(e.cause, HTTPError) and e.cause.status == 403
+                    and e.cause.response.get_header('cf-mitigated') == 'challenge'
+                    and e.cause.response.extensions.get('impersonate') is None):
+                raise
+            cf_cookie_domain = traverse_obj(
+                LenientSimpleCookie(e.cause.response.get_header('set-cookie')),
+                ('__cf_bm', 'domain'))
+            if cf_cookie_domain:
+                self.write_debug(f'Clearing __cf_bm cookie for {cf_cookie_domain}')
+                self.cookiejar.clear(domain=cf_cookie_domain, path='/', name='__cf_bm')
+            msg = 'Got HTTP Error 403 caused by Cloudflare anti-bot challenge; '
+            if not self._downloader._impersonate_target_available(ImpersonateTarget()):
+                msg += ('see  https://github.com/yt-dlp/yt-dlp#impersonation  for '
+                        'how to install the required impersonation dependency, and ')
+            raise ExtractorError(
+                f'{msg}try again with  --extractor-args "generic:impersonate"', expected=True)
+
         new_url = full_response.url
         if new_url != extract_basic_auth(url)[0]:
             self.report_following_redirect(new_url)