+class SearchInfoExtractor(InfoExtractor):
+ """
+ Base class for search queries extractors
+ They accept urls in the format _SEARCH_KEY(|all|[0-9]):{query}
+ """
+ _max_results = 0 # The maximum number of results the extractor can get
+
+ @classmethod
+ def _VALID_URL(cls):
+ return r'%s(?P<prefix>|\d+|all):(?P<query>[\s\S]+)' % cls._SEARCH_KEY
+
+ @classmethod
+ def suitable(cls, url):
+ return re.match(cls._VALID_URL() , url) is not None
+
+ def _real_extract(self, query):
+ mobj = re.match(self._VALID_URL(), query)
+ if mobj is None:
+ raise ExtractorError(u'Invalid search query "%s"' % query)
+
+ prefix = mobj.group('prefix')
+ query = mobj.group('query')
+ if prefix == '':
+ return self._get_n_results(query, 1)
+ elif prefix == 'all':
+ return self._get_n_results(query, self._max_results)
+ else:
+ n = int(prefix)
+ if n <= 0:
+ raise ExtractorError(u'invalid download number %s for query "%s"' % (n, query))
+ elif n > self._max_results:
+ self._downloader.report_warning(u'%s returns max %i results (you requested %i)' % (self._SEARCH_KEY, self._max_results, n))
+ n = self._max_results
+ return self._get_n_results(query, n)
+
+ def _get_n_results(self, query, n):
+ """Get a specified number of results for a query"""
+ raise NotImplementedError("This method must be implemented by sublclasses")
+