1 from __future__
import unicode_literals
13 import xml
.etree
.ElementTree
18 compat_urllib_parse_urlparse
,
31 _NO_DEFAULT
= object()
34 class InfoExtractor(object):
35 """Information Extractor class.
37 Information extractors are the classes that, given a URL, extract
38 information about the video (or videos) the URL refers to. This
39 information includes the real video URL, the video title, author and
40 others. The information is stored in a dictionary which is then
41 passed to the FileDownloader. The FileDownloader processes this
42 information possibly downloading the video to the file system, among
43 other possible outcomes.
45 The dictionaries must include the following fields:
48 title: Video title, unescaped.
50 Additionally, it must contain either a formats entry or a url one:
52 formats: A list of dictionaries for each format available, ordered
53 from worst to best quality.
56 * url Mandatory. The URL of the video file
57 * ext Will be calculated from url if missing
58 * format A human-readable description of the format
59 ("mp4 container with h264/opus").
60 Calculated from the format_id, width, height.
61 and format_note fields if missing.
62 * format_id A short description of the format
63 ("mp4_h264_opus" or "19").
64 Technically optional, but strongly recommended.
65 * format_note Additional info about the format
66 ("3D" or "DASH video")
67 * width Width of the video, if known
68 * height Height of the video, if known
69 * resolution Textual description of width and height
70 * tbr Average bitrate of audio and video in KBit/s
71 * abr Average audio bitrate in KBit/s
72 * acodec Name of the audio codec in use
73 * asr Audio sampling rate in Hertz
74 * vbr Average video bitrate in KBit/s
76 * vcodec Name of the video codec in use
77 * container Name of the container format
78 * filesize The number of bytes, if known in advance
79 * filesize_approx An estimate for the number of bytes
80 * player_url SWF Player URL (used for rtmpdump).
81 * protocol The protocol that will be used for the actual
83 "http", "https", "rtsp", "rtmp", "m3u8" or so.
84 * preference Order number of this format. If this field is
85 present and not None, the formats get sorted
86 by this field, regardless of all other values.
87 -1 for default (order by other properties),
88 -2 or smaller for less than default.
89 * quality Order number of the video quality of this
90 format, irrespective of the file format.
91 -1 for default (order by other properties),
92 -2 or smaller for less than default.
93 * source_preference Order number for this video source
94 (quality takes higher priority)
95 -1 for default (order by other properties),
96 -2 or smaller for less than default.
97 * http_referer HTTP Referer header value to set.
98 * http_method HTTP method to use for the download.
99 * http_headers A dictionary of additional HTTP headers
100 to add to the request.
101 * http_post_data Additional data to send with a POST
103 url: Final video URL.
104 ext: Video filename extension.
105 format: The video format, defaults to ext (used for --get-format)
106 player_url: SWF Player URL (used for rtmpdump).
108 The following fields are optional:
110 display_id An alternative identifier for the video, not necessarily
111 unique, but available before title. Typically, id is
112 something like "4234987", title "Dancing naked mole rats",
113 and display_id "dancing-naked-mole-rats"
114 thumbnails: A list of dictionaries, with the following entries:
116 * "width" (optional, int)
117 * "height" (optional, int)
118 * "resolution" (optional, string "{width}x{height"},
120 thumbnail: Full URL to a video thumbnail image.
121 description: One-line video description.
122 uploader: Full name of the video uploader.
123 timestamp: UNIX timestamp of the moment the video became available.
124 upload_date: Video upload date (YYYYMMDD).
125 If not explicitly set, calculated from timestamp.
126 uploader_id: Nickname or id of the video uploader.
127 location: Physical location where the video was filmed.
128 subtitles: The subtitle file contents as a dictionary in the format
129 {language: subtitles}.
130 duration: Length of the video in seconds, as an integer.
131 view_count: How many users have watched the video on the platform.
132 like_count: Number of positive ratings of the video
133 dislike_count: Number of negative ratings of the video
134 comment_count: Number of comments on the video
135 age_limit: Age restriction for the video, as an integer (years)
136 webpage_url: The url to the video webpage, if given to youtube-dl it
137 should allow to get the same result again. (It will be set
138 by YoutubeDL if it's missing)
139 categories: A list of categories that the video falls in, for example
141 is_live: True, False, or None (=unknown). Whether this video is a
142 live stream that goes on instead of a fixed-length video.
144 Unless mentioned otherwise, the fields should be Unicode strings.
146 Unless mentioned otherwise, None is equivalent to absence of information.
148 Subclasses of this one should re-define the _real_initialize() and
149 _real_extract() methods and define a _VALID_URL regexp.
150 Probably, they should also be added to the list of extractors.
152 Finally, the _WORKING attribute should be set to False for broken IEs
153 in order to warn the users and skip the tests.
160 def __init__(self
, downloader
=None):
161 """Constructor. Receives an optional downloader."""
163 self
.set_downloader(downloader
)
166 def suitable(cls
, url
):
167 """Receives a URL and returns True if suitable for this IE."""
169 # This does not use has/getattr intentionally - we want to know whether
170 # we have cached the regexp for *this* class, whereas getattr would also
171 # match the superclass
172 if '_VALID_URL_RE' not in cls
.__dict
__:
173 cls
._VALID
_URL
_RE
= re
.compile(cls
._VALID
_URL
)
174 return cls
._VALID
_URL
_RE
.match(url
) is not None
177 def _match_id(cls
, url
):
178 if '_VALID_URL_RE' not in cls
.__dict
__:
179 cls
._VALID
_URL
_RE
= re
.compile(cls
._VALID
_URL
)
180 m
= cls
._VALID
_URL
_RE
.match(url
)
186 """Getter method for _WORKING."""
189 def initialize(self
):
190 """Initializes an instance (authentication, etc)."""
192 self
._real
_initialize
()
195 def extract(self
, url
):
196 """Extracts URL information and returns it in list of dicts."""
198 return self
._real
_extract
(url
)
200 def set_downloader(self
, downloader
):
201 """Sets the downloader for this IE."""
202 self
._downloader
= downloader
204 def _real_initialize(self
):
205 """Real initialization process. Redefine in subclasses."""
208 def _real_extract(self
, url
):
209 """Real extraction process. Redefine in subclasses."""
214 """A string for getting the InfoExtractor with get_info_extractor"""
215 return cls
.__name
__[:-2]
219 return type(self
).__name
__[:-2]
221 def _request_webpage(self
, url_or_request
, video_id
, note
=None, errnote
=None, fatal
=True):
222 """ Returns the response handle """
224 self
.report_download_webpage(video_id
)
225 elif note
is not False:
227 self
.to_screen('%s' % (note
,))
229 self
.to_screen('%s: %s' % (video_id
, note
))
231 return self
._downloader
.urlopen(url_or_request
)
232 except (compat_urllib_error
.URLError
, compat_http_client
.HTTPException
, socket
.error
) as err
:
236 errnote
= 'Unable to download webpage'
237 errmsg
= '%s: %s' % (errnote
, compat_str(err
))
239 raise ExtractorError(errmsg
, sys
.exc_info()[2], cause
=err
)
241 self
._downloader
.report_warning(errmsg
)
244 def _download_webpage_handle(self
, url_or_request
, video_id
, note
=None, errnote
=None, fatal
=True):
245 """ Returns a tuple (page content as string, URL handle) """
246 # Strip hashes from the URL (#1038)
247 if isinstance(url_or_request
, (compat_str
, str)):
248 url_or_request
= url_or_request
.partition('#')[0]
250 urlh
= self
._request
_webpage
(url_or_request
, video_id
, note
, errnote
, fatal
)
254 content
= self
._webpage
_read
_content
(urlh
, url_or_request
, video_id
, note
, errnote
, fatal
)
255 return (content
, urlh
)
257 def _webpage_read_content(self
, urlh
, url_or_request
, video_id
, note
=None, errnote
=None, fatal
=True):
258 content_type
= urlh
.headers
.get('Content-Type', '')
259 webpage_bytes
= urlh
.read()
260 m
= re
.match(r
'[a-zA-Z0-9_.-]+/[a-zA-Z0-9_.-]+\s*;\s*charset=(.+)', content_type
)
262 encoding
= m
.group(1)
264 m
= re
.search(br
'<meta[^>]+charset=[\'"]?([^\'")]+)[ /\'">]',
265 webpage_bytes[:1024])
267 encoding = m.group(1).decode('ascii')
268 elif webpage_bytes.startswith(b'\xff\xfe'):
272 if self._downloader.params.get('dump_intermediate_pages', False):
274 url = url_or_request.get_full_url()
275 except AttributeError:
277 self.to_screen('Dumping request to ' + url)
278 dump = base64.b64encode(webpage_bytes).decode('ascii')
279 self._downloader.to_screen(dump)
280 if self._downloader.params.get('write_pages', False):
282 url = url_or_request.get_full_url()
283 except AttributeError:
285 basen = '%s_%s' % (video_id, url)
287 h = '___' + hashlib.md5(basen.encode('utf-8')).hexdigest()
288 basen = basen[:240 - len(h)] + h
289 raw_filename = basen + '.dump'
290 filename = sanitize_filename(raw_filename, restricted=True)
291 self.to_screen('Saving request to ' + filename)
292 # Working around MAX_PATH limitation on Windows (see
293 # http://msdn.microsoft.com/en-us/library/windows/desktop/aa365247(v=vs.85).aspx)
295 absfilepath = os.path.abspath(filename)
296 if len(absfilepath) > 259:
297 filename = '\\\\?\\' + absfilepath
298 with open(filename, 'wb') as outf:
299 outf.write(webpage_bytes)
302 content = webpage_bytes.decode(encoding, 'replace')
304 content = webpage_bytes.decode('utf-8', 'replace')
306 if ('<title>Access to this site is blocked</title>' in content and
307 'Websense' in content[:512]):
308 msg = 'Access to this webpage has been blocked by Websense filtering software in your network.'
309 blocked_iframe = self._html_search_regex(
310 r'<iframe src="([^
"]+)"', content,
311 'Websense information URL
', default=None)
313 msg += ' Visit
%s for more details
' % blocked_iframe
314 raise ExtractorError(msg, expected=True)
318 def _download_webpage(self, url_or_request, video_id, note=None, errnote=None, fatal=True):
319 """ Returns the data of the page as a string """
320 res = self._download_webpage_handle(url_or_request, video_id, note, errnote, fatal)
327 def _download_xml(self, url_or_request, video_id,
328 note='Downloading XML
', errnote='Unable to download XML
',
329 transform_source=None, fatal=True):
330 """Return the xml as an xml.etree.ElementTree.Element"""
331 xml_string = self._download_webpage(
332 url_or_request, video_id, note, errnote, fatal=fatal)
333 if xml_string is False:
336 xml_string = transform_source(xml_string)
337 return xml.etree.ElementTree.fromstring(xml_string.encode('utf
-8'))
339 def _download_json(self, url_or_request, video_id,
340 note='Downloading JSON metadata
',
341 errnote='Unable to download JSON metadata
',
342 transform_source=None,
344 json_string = self._download_webpage(
345 url_or_request, video_id, note, errnote, fatal=fatal)
346 if (not fatal) and json_string is False:
349 json_string = transform_source(json_string)
351 return json.loads(json_string)
352 except ValueError as ve:
353 errmsg = '%s: Failed to parse JSON
' % video_id
355 raise ExtractorError(errmsg, cause=ve)
357 self.report_warning(errmsg + str(ve))
359 def report_warning(self, msg, video_id=None):
360 idstr = '' if video_id is None else '%s: ' % video_id
361 self._downloader.report_warning(
362 '[%s] %s%s' % (self.IE_NAME, idstr, msg))
364 def to_screen(self, msg):
365 """Print msg to screen, prefixing it with '[ie_name
]'"""
366 self._downloader.to_screen('[%s] %s' % (self.IE_NAME, msg))
368 def report_extraction(self, id_or_name):
369 """Report information extraction."""
370 self.to_screen('%s: Extracting information
' % id_or_name)
372 def report_download_webpage(self, video_id):
373 """Report webpage download."""
374 self.to_screen('%s: Downloading webpage
' % video_id)
376 def report_age_confirmation(self):
377 """Report attempt to confirm age."""
378 self.to_screen('Confirming age
')
380 def report_login(self):
381 """Report attempt to log in."""
382 self.to_screen('Logging
in')
384 #Methods for following #608
386 def url_result(url, ie=None, video_id=None):
387 """Returns a url that points to a page that should be processed"""
388 #TODO: ie should be the class used for getting the info
389 video_info = {'_type
': 'url
',
392 if video_id is not None:
393 video_info['id'] = video_id
396 def playlist_result(entries, playlist_id=None, playlist_title=None):
397 """Returns a playlist"""
398 video_info = {'_type
': 'playlist
',
401 video_info['id'] = playlist_id
403 video_info['title
'] = playlist_title
406 def _search_regex(self, pattern, string, name, default=_NO_DEFAULT, fatal=True, flags=0):
408 Perform a regex search on the given string, using a single or a list of
409 patterns returning the first matching group.
410 In case of failure return a default value or raise a WARNING or a
411 RegexNotFoundError, depending on fatal, specifying the field name.
413 if isinstance(pattern, (str, compat_str, compiled_regex_type)):
414 mobj = re.search(pattern, string, flags)
417 mobj = re.search(p, string, flags)
421 if os.name != 'nt
' and sys.stderr.isatty():
422 _name = '\033[0;34m
%s\033[0m
' % name
427 # return the first matching group
428 return next(g for g in mobj.groups() if g is not None)
429 elif default is not _NO_DEFAULT:
432 raise RegexNotFoundError('Unable to extract
%s' % _name)
434 self._downloader.report_warning('unable to extract
%s; '
435 'please report this issue on http
://yt
-dl
.org
/bug
' % _name)
438 def _html_search_regex(self, pattern, string, name, default=_NO_DEFAULT, fatal=True, flags=0):
440 Like _search_regex, but strips HTML tags and unescapes entities.
442 res = self._search_regex(pattern, string, name, default, fatal, flags)
444 return clean_html(res).strip()
448 def _get_login_info(self):
450 Get the the login info as (username, password)
451 It will look in the netrc file using the _NETRC_MACHINE value
452 If there's no info available
, return (None, None)
454 if self._downloader is None:
459 downloader_params = self._downloader.params
461 # Attempt to use provided username and password or .netrc data
462 if downloader_params.get('username', None) is not None:
463 username = downloader_params['username']
464 password = downloader_params['password']
465 elif downloader_params.get('usenetrc', False):
467 info = netrc.netrc().authenticators(self._NETRC_MACHINE)
472 raise netrc.NetrcParseError('No authenticators for %s' % self._NETRC_MACHINE)
473 except (IOError, netrc.NetrcParseError) as err:
474 self._downloader.report_warning('parsing .netrc: %s' % compat_str(err))
476 return (username, password)
478 def _get_tfa_info(self):
480 Get the two
-factor authentication info
481 TODO
- asking the user will be required
for sms
/phone verify
482 currently just uses the command line option
483 If there
's no info available, return None
485 if self._downloader is None:
487 downloader_params = self._downloader.params
489 if downloader_params.get('twofactor
', None) is not None:
490 return downloader_params['twofactor
']
494 # Helper functions for extracting OpenGraph info
496 def _og_regexes(prop):
497 content_re = r'content
=(?
:"([^>]+?)"|
\'([^
>]+?
)\')'
498 property_re = r'(?
:name|
property)=[\'"]og:%s[\'"]' % re.escape(prop)
499 template = r'<meta
[^
>]+?
%s[^
>]+?
%s'
501 template % (property_re, content_re),
502 template % (content_re, property_re),
505 def _og_search_property(self, prop, html, name=None, **kargs):
507 name = 'OpenGraph
%s' % prop
508 escaped = self._search_regex(self._og_regexes(prop), html, name, flags=re.DOTALL, **kargs)
511 return unescapeHTML(escaped)
513 def _og_search_thumbnail(self, html, **kargs):
514 return self._og_search_property('image
', html, 'thumbnail url
', fatal=False, **kargs)
516 def _og_search_description(self, html, **kargs):
517 return self._og_search_property('description
', html, fatal=False, **kargs)
519 def _og_search_title(self, html, **kargs):
520 return self._og_search_property('title
', html, **kargs)
522 def _og_search_video_url(self, html, name='video url
', secure=True, **kargs):
523 regexes = self._og_regexes('video
') + self._og_regexes('video
:url
')
525 regexes = self._og_regexes('video
:secure_url
') + regexes
526 return self._html_search_regex(regexes, html, name, **kargs)
528 def _og_search_url(self, html, **kargs):
529 return self._og_search_property('url
', html, **kargs)
531 def _html_search_meta(self, name, html, display_name=None, fatal=False, **kwargs):
532 if display_name is None:
534 return self._html_search_regex(
536 (?=[^>]+(?:itemprop|name|property)=["\']?%s["\']?)
537 [^>]+content=["\']([^"\']+)["\']''' % re.escape(name),
538 html, display_name, fatal=fatal, **kwargs)
540 def _dc_search_uploader(self, html):
541 return self._html_search_meta('dc
.creator
', html, 'uploader
')
543 def _rta_search(self, html):
544 # See http://www.rtalabel.org/index.php?content=howtofaq#single
545 if re.search(r'(?ix
)<meta\s
+name
="rating"\s
+'
546 r' content
="RTA-5042-1996-1400-1577-RTA"',
551 def _media_rating_search(self, html):
552 # See http://www.tjg-designs.com/WP/metadata-code-examples-adding-metadata-to-your-web-pages/
553 rating = self._html_search_meta('rating
', html)
565 return RATING_TABLE.get(rating.lower(), None)
567 def _twitter_search_player(self, html):
568 return self._html_search_meta('twitter
:player
', html,
569 'twitter card player
')
571 def _sort_formats(self, formats):
573 raise ExtractorError('No video formats found
')
576 # TODO remove the following workaround
577 from ..utils import determine_ext
578 if not f.get('ext
') and 'url
' in f:
579 f['ext
'] = determine_ext(f['url
'])
581 preference = f.get('preference
')
582 if preference is None:
583 proto = f.get('protocol
')
585 proto = compat_urllib_parse_urlparse(f.get('url
', '')).scheme
587 preference = 0 if proto in ['http
', 'https
'] else -0.1
588 if f.get('ext
') in ['f4f
', 'f4m
']: # Not yet supported
591 if f.get('vcodec
') == 'none
': # audio only
592 if self._downloader.params.get('prefer_free_formats
'):
593 ORDER = ['aac
', 'mp3
', 'm4a
', 'webm
', 'ogg
', 'opus
']
595 ORDER = ['webm
', 'opus
', 'ogg
', 'mp3
', 'aac
', 'm4a
']
598 audio_ext_preference = ORDER.index(f['ext
'])
600 audio_ext_preference = -1
602 if self._downloader.params.get('prefer_free_formats
'):
603 ORDER = ['flv
', 'mp4
', 'webm
']
605 ORDER = ['webm
', 'flv
', 'mp4
']
607 ext_preference = ORDER.index(f['ext
'])
610 audio_ext_preference = 0
614 f.get('quality
') if f.get('quality
') is not None else -1,
615 f.get('height
') if f.get('height
') is not None else -1,
616 f.get('width
') if f.get('width
') is not None else -1,
618 f.get('tbr
') if f.get('tbr
') is not None else -1,
619 f.get('vbr
') if f.get('vbr
') is not None else -1,
620 f.get('abr
') if f.get('abr
') is not None else -1,
621 audio_ext_preference,
622 f.get('fps
') if f.get('fps
') is not None else -1,
623 f.get('filesize
') if f.get('filesize
') is not None else -1,
624 f.get('filesize_approx
') if f.get('filesize_approx
') is not None else -1,
625 f.get('source_preference
') if f.get('source_preference
') is not None else -1,
628 formats.sort(key=_formats_key)
630 def http_scheme(self):
631 """ Either "http:" or "https:", depending on the user's preferences
"""
634 if self._downloader.params.get('prefer_insecure', False)
637 def _proto_relative_url(self, url, scheme=None):
640 if url.startswith('//'):
642 scheme = self.http_scheme()
647 def _sleep(self, timeout, video_id, msg_template=None):
648 if msg_template is None:
649 msg_template = '%(video_id)s: Waiting for %(timeout)s seconds'
650 msg = msg_template % {'video_id': video_id, 'timeout': timeout}
654 def _extract_f4m_formats(self, manifest_url, video_id):
655 manifest = self._download_xml(
656 manifest_url, video_id, 'Downloading f4m manifest',
657 'Unable to download f4m manifest')
660 media_nodes = manifest.findall('{http://ns.adobe.com/f4m/1.0}media')
661 for i, media_el in enumerate(media_nodes):
662 tbr = int_or_none(media_el.attrib.get('bitrate'))
663 format_id = 'f4m-%d' % (i if tbr is None else tbr)
665 'format_id': format_id,
669 'width': int_or_none(media_el.attrib.get('width')),
670 'height': int_or_none(media_el.attrib.get('height')),
672 self._sort_formats(formats)
676 def _extract_m3u8_formats(self, m3u8_url, video_id, ext=None,
677 entry_protocol='m3u8', preference=None):
680 'format_id': 'm3u8-meta',
685 'resolution': 'multiple',
686 'format_note': 'Quality selection URL',
689 format_url = lambda u: (
691 if re.match(r'^https?://', u)
692 else compat_urlparse.urljoin(m3u8_url, u))
694 m3u8_doc = self._download_webpage(
696 note='Downloading m3u8 information',
697 errnote='Failed to download m3u8 information')
700 r'(?P<key>[a-zA-Z_-]+)=(?P<val>"[^"]+"|[^",]+)(?:,|$)')
701 for line in m3u8_doc.splitlines():
702 if line.startswith('#EXT-X-STREAM-INF:'):
704 for m in kv_rex.finditer(line):
706 if v.startswith('"'):
708 last_info[m.group('key')] = v
709 elif line.startswith('#') or not line.strip():
712 if last_info is None:
713 formats.append({'url': format_url(line)})
715 tbr = int_or_none(last_info.get('BANDWIDTH'), scale=1000)
718 'format_id': 'm3u8-%d' % (tbr if tbr else len(formats)),
719 'url': format_url(line.strip()),
722 'protocol': entry_protocol,
723 'preference': preference,
725 codecs = last_info.get('CODECS')
727 # TODO: looks like video codec is not always necessarily goes first
728 va_codecs = codecs.split(',')
730 f['vcodec'] = va_codecs[0].partition('.')[0]
731 if len(va_codecs) > 1 and va_codecs[1]:
732 f['acodec'] = va_codecs[1].partition('.')[0]
733 resolution = last_info.get('RESOLUTION')
735 width_str, height_str = resolution.split('x')
736 f['width'] = int(width_str)
737 f['height'] = int(height_str)
740 self._sort_formats(formats)
743 def _live_title(self, name):
744 """ Generate the title
for a live video
"""
745 now = datetime.datetime.now()
746 now_str = now.strftime("%Y-%m-%d %H:%M")
747 return name + ' ' + now_str
749 def _int(self, v, name, fatal=False, **kwargs):
750 res = int_or_none(v, **kwargs)
751 if 'get_attr' in kwargs:
752 print(getattr(v, kwargs['get_attr']))
754 msg = 'Failed to extract %s: Could not parse value %r' % (name, v)
756 raise ExtractorError(msg)
758 self._downloader.report_warning(msg)
761 def _float(self, v, name, fatal=False, **kwargs):
762 res = float_or_none(v, **kwargs)
764 msg = 'Failed to extract %s: Could not parse value %r' % (name, v)
766 raise ExtractorError(msg)
768 self._downloader.report_warning(msg)
772 class SearchInfoExtractor(InfoExtractor):
774 Base
class for paged search queries extractors
.
775 They accept urls
in the format
_SEARCH_KEY(|all|
[0-9]):{query}
776 Instances should define _SEARCH_KEY
and _MAX_RESULTS
.
780 def _make_valid_url(cls):
781 return r'%s(?P<prefix>|[1-9][0-9]*|all):(?P<query>[\s\S]+)' % cls._SEARCH_KEY
784 def suitable(cls, url):
785 return re.match(cls._make_valid_url(), url) is not None
787 def _real_extract(self, query):
788 mobj = re.match(self._make_valid_url(), query)
790 raise ExtractorError('Invalid search query "%s"' % query)
792 prefix = mobj.group('prefix')
793 query = mobj.group('query')
795 return self._get_n_results(query, 1)
796 elif prefix == 'all':
797 return self._get_n_results(query, self._MAX_RESULTS)
801 raise ExtractorError('invalid download number %s for query "%s"' % (n, query))
802 elif n > self._MAX_RESULTS:
803 self._downloader.report_warning('%s returns max %i results (you requested %i)' % (self._SEARCH_KEY, self._MAX_RESULTS, n))
804 n = self._MAX_RESULTS
805 return self._get_n_results(query, n)
807 def _get_n_results(self, query, n):
808 """Get a specified number of results
for a query
"""
809 raise NotImplementedError("This method must be implemented by subclasses")
812 def SEARCH_KEY(self):
813 return self._SEARCH_KEY