283 lines
10 KiB
Python
283 lines
10 KiB
Python
import sys
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# This can only be tested by using different python versions, therefore it is not covered by coverage.py
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if sys.version_info.major == 2: # pragma: no cover
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reload(sys)
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sys.setdefaultencoding('utf-8')
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import json
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from xml.etree import ElementTree
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import re
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from ._html_unescaping import unescape
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from ._errors import VideoUnavailable, NoTranscriptFound, TranscriptsDisabled
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from ._settings import WATCH_URL
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class TranscriptListFetcher():
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def __init__(self, http_client):
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self._http_client = http_client
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def fetch(self, video_id):
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return TranscriptList.build(
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self._http_client,
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video_id,
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self._extract_captions_json(self._fetch_html(video_id), video_id)
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)
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def _extract_captions_json(self, html, video_id):
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splitted_html = html.split('"captions":')
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if len(splitted_html) <= 1:
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if '"playabilityStatus":' not in html:
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raise VideoUnavailable(video_id)
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raise TranscriptsDisabled(video_id)
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return json.loads(splitted_html[1].split(',"videoDetails')[0].replace('\n', ''))[
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'playerCaptionsTracklistRenderer'
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]
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def _fetch_html(self, video_id):
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return self._http_client.get(WATCH_URL.format(video_id=video_id)).text.replace(
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'\\u0026', '&'
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).replace(
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'\\', ''
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)
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class TranscriptList():
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"""
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This object represents a list of transcripts. It can be iterated over to list all transcripts which are available
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for a given YouTube video. Also it provides functionality to search for a transcript in a given language.
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"""
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# TODO implement iterator
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def __init__(self, video_id, manually_created_transcripts, generated_transcripts):
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"""
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The constructor is only for internal use. Use the static build method instead.
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:param video_id: the id of the video this TranscriptList is for
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:type video_id: str
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:param manually_created_transcripts: dict mapping language codes to the manually created transcripts
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:type manually_created_transcripts: dict[str, Transcript]
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:param generated_transcripts: dict mapping language codes to the generated transcripts
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:type generated_transcripts: dict[str, Transcript]
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"""
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self.video_id = video_id
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self._manually_created_transcripts = manually_created_transcripts
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self._generated_transcripts = generated_transcripts
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@staticmethod
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def build(http_client, video_id, captions_json):
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"""
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Factory method for TranscriptList.
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:param http_client: http client which is used to make the transcript retrieving http calls
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:type http_client: requests.Session
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:param video_id: the id of the video this TranscriptList is for
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:type video_id: str
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:param captions_json: the JSON parsed from the YouTube pages static HTML
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:type captions_json: dict
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:return: the created TranscriptList
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:rtype TranscriptList
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"""
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translation_languages = [
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{
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'language': translation_language['languageName']['simpleText'],
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'language_code': translation_language['languageCode'],
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} for translation_language in captions_json['translationLanguages']
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]
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manually_created_transcripts = {}
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generated_transcripts = {}
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for caption in captions_json['captionTracks']:
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if caption.get('kind', '') == 'asr':
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transcript_dict = generated_transcripts
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else:
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transcript_dict = manually_created_transcripts
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transcript_dict[caption['languageCode']] = Transcript(
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http_client,
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video_id,
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caption['baseUrl'],
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caption['name']['simpleText'],
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caption['languageCode'],
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caption.get('kind', '') == 'asr',
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translation_languages if caption['isTranslatable'] else []
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)
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return TranscriptList(
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video_id,
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manually_created_transcripts,
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generated_transcripts,
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)
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def find_transcript(self, language_codes):
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"""
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Finds a transcript for a given language code. Manually created transcripts are returned first and only if none
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are found, generated transcripts are used. If you only want generated transcripts use
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find_manually_created_transcript instead.
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:param language_codes: A list of language codes in a descending priority. For example, if this is set to
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['de', 'en'] it will first try to fetch the german transcript (de) and then fetch the english transcript (en) if
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it fails to do so.
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:type languages: [str]
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:return: the found Transcript
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:rtype: Transcript
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:raises: NoTranscriptFound
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"""
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try:
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return self.find_manually_created_transcript(language_codes)
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except NoTranscriptFound:
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pass
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return self.find_generated_transcript(language_codes)
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def find_generated_transcript(self, language_codes):
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"""
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Finds a automatically generated transcript for a given language code.
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:param language_codes: A list of language codes in a descending priority. For example, if this is set to
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['de', 'en'] it will first try to fetch the german transcript (de) and then fetch the english transcript (en) if
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it fails to do so.
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:type languages: [str]
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:return: the found Transcript
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:rtype: Transcript
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:raises: NoTranscriptFound
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"""
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return self._find_transcript(language_codes, generated=True)
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def find_manually_created_transcript(self, language_codes):
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"""
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Finds a manually created transcript for a given language code.
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:param language_codes: A list of language codes in a descending priority. For example, if this is set to
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['de', 'en'] it will first try to fetch the german transcript (de) and then fetch the english transcript (en) if
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it fails to do so.
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:type languages: [str]
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:return: the found Transcript
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:rtype: Transcript
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:raises: NoTranscriptFound
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"""
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return self._find_transcript(language_codes, generated=False)
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def _find_transcript(self, language_codes, generated):
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transcripts = self._generated_transcripts if generated else self._manually_created_transcripts
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for language_code in language_codes:
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if language_code in transcripts:
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return transcripts[language_code]
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raise NoTranscriptFound(
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self.video_id,
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language_codes,
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self
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)
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def __str__(self):
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return (
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'For this video ({video_id}) transcripts are available in the following languages:\n\n'
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'(MANUALLY CREATED)\n'
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'{available_manually_created_transcript_languages}\n\n'
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'(GENERATED)\n'
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'{available_generated_transcripts}'
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).format(
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video_id=self.video_id,
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available_manually_created_transcript_languages=self._get_language_description(
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self._manually_created_transcripts.values()
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),
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available_generated_transcripts=self._get_language_description(
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self._generated_transcripts.values()
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),
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)
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def _get_language_description(self, transcripts):
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return '\n'.join(
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' - {transcript}'.format(transcript=str(transcript))
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for transcript in transcripts
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) if transcripts else 'None'
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class Transcript():
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def __init__(self, http_client, video_id, url, language, language_code, is_generated, translation_languages):
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"""
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You probably don't want to initialize this directly. Usually you'll access Transcript objects using a
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TranscriptList.
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:param http_client: http client which is used to make the transcript retrieving http calls
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:type http_client: requests.Session
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:param video_id: the id of the video this TranscriptList is for
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:type video_id: str
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:param url: the url which needs to be called to fetch the transcript
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:param language: the name of the language this transcript uses
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:param language_code:
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:param is_generated:
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:param translation_languages:
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"""
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self._http_client = http_client
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self.video_id = video_id
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self._url = url
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self.language = language
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self.language_code = language_code
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self.is_generated = is_generated
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self.translation_languages = translation_languages
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def fetch(self):
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"""
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Loads the actual transcript data.
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:return: a list of dictionaries containing the 'text', 'start' and 'duration' keys
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:rtype: [{'text': str, 'start': float, 'end': float}]
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"""
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return _TranscriptParser().parse(
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self._http_client.get(self._url).text
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)
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def __str__(self):
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return '{language_code} ("{language}")'.format(
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language=self.language,
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language_code=self.language_code,
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)
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# TODO integrate translations in future release
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# @property
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# def is_translatable(self):
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# return len(self.translation_languages) > 0
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#
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#
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# class TranslatableTranscript(Transcript):
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# def __init__(self, http_client, url, translation_languages):
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# super(TranslatableTranscript, self).__init__(http_client, url)
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# self._translation_languages = translation_languages
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# self._translation_language_codes = {language['language_code'] for language in translation_languages}
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#
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#
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# def translate(self, language_code):
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# if language_code not in self._translation_language_codes:
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# raise TranslatableTranscript.TranslationLanguageNotAvailable()
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#
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# return Transcript(
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# self._http_client,
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# '{url}&tlang={language_code}'.format(url=self._url, language_code=language_code)
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# )
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class _TranscriptParser():
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HTML_TAG_REGEX = re.compile(r'<[^>]*>', re.IGNORECASE)
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def parse(self, plain_data):
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return [
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{
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'text': re.sub(self.HTML_TAG_REGEX, '', unescape(xml_element.text)),
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'start': float(xml_element.attrib['start']),
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'duration': float(xml_element.attrib['dur']),
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}
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for xml_element in ElementTree.fromstring(plain_data)
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if xml_element.text is not None
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]
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