diff options
Diffstat (limited to 'youtube_dl/extractor/common.py')
| -rw-r--r-- | youtube_dl/extractor/common.py | 51 |
1 files changed, 38 insertions, 13 deletions
diff --git a/youtube_dl/extractor/common.py b/youtube_dl/extractor/common.py index 549781186..7f416d312 100644 --- a/youtube_dl/extractor/common.py +++ b/youtube_dl/extractor/common.py @@ -83,6 +83,7 @@ from ..utils import ( urljoin, url_basename, url_or_none, + variadic, xpath_element, xpath_text, xpath_with_ns, @@ -371,9 +372,22 @@ class InfoExtractor(object): title, description etc. - Subclasses of this one should re-define the _real_initialize() and - _real_extract() methods and define a _VALID_URL regexp. - Probably, they should also be added to the list of extractors. + A subclass of InfoExtractor must be defined to handle each specific site (or + several sites). Such a concrete subclass should be added to the list of + extractors. It should also: + * define its _VALID_URL attribute as a regexp, or a Sequence of alternative + regexps (but see below) + * re-define the _real_extract() method + * optionally re-define the _real_initialize() method. + + An extractor subclass may also override suitable() if necessary, but the + function signature must be preserved and the function must import everything + it needs (except other extractors), so that lazy_extractors works correctly. + If the subclass's suitable() and _real_extract() functions avoid using + _VALID_URL, the subclass need not set that class attribute. + + An abstract subclass of InfoExtractor may be used to simplify implementation + within an extractor module; it should not be added to the list of extractors. _GEO_BYPASS attribute may be set to False in order to disable geo restriction bypass mechanisms for a particular extractor. @@ -409,21 +423,32 @@ class InfoExtractor(object): self.set_downloader(downloader) @classmethod - def suitable(cls, url): - """Receives a URL and returns True if suitable for this IE.""" - + def __match_valid_url(cls, url): # This does not use has/getattr intentionally - we want to know whether - # we have cached the regexp for *this* class, whereas getattr would also - # match the superclass + # we have cached the regexp for cls, whereas getattr would also + # match its superclass if '_VALID_URL_RE' not in cls.__dict__: - cls._VALID_URL_RE = re.compile(cls._VALID_URL) - return cls._VALID_URL_RE.match(url) is not None + # _VALID_URL can now be a list/tuple of patterns + cls._VALID_URL_RE = tuple(map(re.compile, variadic(cls._VALID_URL))) + # 20% faster than next(filter(None, (p.match(url) for p in cls._VALID_URL_RE)), None) in 2.7 + for p in cls._VALID_URL_RE: + p = p.match(url) + if p: + return p + + # The public alias can safely be overridden, as in some back-ports + _match_valid_url = __match_valid_url + + @classmethod + def suitable(cls, url): + """Receives a URL and returns True if suitable for this IE.""" + # This function must import everything it needs (except other extractors), + # so that lazy_extractors works correctly + return cls.__match_valid_url(url) is not None @classmethod def _match_id(cls, url): - if '_VALID_URL_RE' not in cls.__dict__: - cls._VALID_URL_RE = re.compile(cls._VALID_URL) - m = cls._VALID_URL_RE.match(url) + m = cls.__match_valid_url(url) assert m return compat_str(m.group('id')) |