+ @staticmethod
+ def _check_error(json_string, key_or_keys):
+ keys = [key_or_keys] if isinstance(key_or_keys, compat_str) else key_or_keys
+ for key in keys:
+ error = json_string.get(key)
+ if error:
+ raise ExtractorError('Unable to login: %s' % error, expected=True)
+
+ def _login_step(self, form_html, fallback_action_url, extra_form_data, note, referrer_url):
+ action_url = self._search_regex(
+ r'<form[^>]+action=(["\'])(?P<url>.+?)\1', form_html,
+ 'post url', default=fallback_action_url, group='url')
+
+ if not action_url.startswith('http'):
+ action_url = compat_urlparse.urljoin(self._SIGNIN_URL, action_url)
+
+ form_data = self._hidden_inputs(form_html)
+ form_data.update(extra_form_data)
+
+ response = self._download_json(
+ action_url, None, note,
+ data=urlencode_postdata(form_data),
+ headers={
+ 'Referer': referrer_url,
+ 'X-Requested-With': 'XMLHttpRequest',
+ }, expected_status=(418, 500, ))
+
+ self._check_error(response, ('email', 'password', 'ErrorMessage'))
+
+ return response, action_url
+