GH262: Rework URL filter logic [Based on #277]

src/fundus/scraping/html.py

@@ -29,7 +29,7 @@
 
 from fundus.logging import basic_logger
 from fundus.scraping.filter import URLFilter, inverse
-from fundus.utils.more_async import async_next, make_iterable_async
+from fundus.utils.more_async import make_iterable_async
 
 _default_header = {"user-agent": "Fundus"}
 
@@ -252,25 +252,26 @@ def __init__(
  else:
  self.url_source = make_iterable_async(url_source)
  self.publisher = publisher
- self.url_filter = [] if not url_filter else [url_filter]
+ self.url_filter = url_filter
  self.request_header = request_header or _default_header
  if isinstance(url_source, URLSource):
  url_source.set_header(self.request_header)
 
- def add_url_filter(self, url_filter: URLFilter) -> None:
- self.url_filter.append(url_filter)
+ async def fetch(self, url_filter: Optional[URLFilter] = None) -> AsyncIterator[Optional[HTML]]:
+ combined_filters: List[URLFilter] = ([self.url_filter] if self.url_filter else []) + (
+ [url_filter] if url_filter else []
+ )
 
- def _filter(self, url: str) -> bool:
- return any(url_filter(url) for url_filter in self.url_filter)
+  def filter_url(u: str) -> bool:
+  return any(f(u) for f in combined_filters)
 
- async def fetch(self) -> AsyncIterator[Optional[HTML]]:
  async for url in self.url_source:
  if not validators.url(url):
  basic_logger.debug(f"Skipped requested URL '{url}' because the URL is malformed")
  yield None
  continue
 
- if self._filter(url):
+ if filter_url(url):
  basic_logger.debug(f"Skipped requested URL '{url}' because of URL filter")
  yield None
  continue
@@ -279,8 +280,8 @@ async def fetch(self) -> AsyncIterator[Optional[HTML]]:
 
  try:
  async with session.get(url, headers=self.request_header) as response:
- if self._filter(str(response.url)):
- basic_logger.debug(f"Skipped responded URL '{url}' because of URL filter")
+ if filter_url(str(response.url)):
+ basic_logger.debug(f"Skipped responded URL '{str(response.url)}' because of URL filter")
  yield None
  continue
  html = await response.text()

src/fundus/scraping/pipeline.py

@@ -112,25 +112,19 @@ def constant_delay() -> float:
  else:
  return delay
 
- def build_unique_url_filter() -> URLFilter:
- return lambda url: url in response_cache
+ def build_url_filter() -> URLFilter:
+ def _filter(url: str) -> bool:
+ return (url_filter is not None and url_filter(url)) or (only_unique and url in response_cache)
 
- # build filters and delay. this is for readability and typeguard reasons
- extraction_filter = build_extraction_filter()
- unique_url_filter = build_unique_url_filter() if only_unique else None
- final_delay = build_delay()
+ return _filter
 
- for scraper in self.scrapers:
- for source in scraper.sources:
- if url_filter:
- source.add_url_filter(url_filter=url_filter)
- if unique_url_filter:
- source.add_url_filter(url_filter=unique_url_filter)
+ final_delay = build_delay()
 
  async_article_iterators: List[AsyncIterator[Optional[Article]]] = [
  scraper.scrape(
  error_handling=error_handling,
- extraction_filter=extraction_filter,
+ extraction_filter=build_extraction_filter(),
+ url_filter=build_url_filter(),
  )
  for scraper in self.scrapers
  ]

src/fundus/scraping/scraper.py

@@ -5,7 +5,7 @@
 from fundus.logging import basic_logger
 from fundus.parser import ParserProxy
 from fundus.scraping.article import Article
-from fundus.scraping.filter import ExtractionFilter, Requires
+from fundus.scraping.filter import ExtractionFilter, Requires, URLFilter
 from fundus.scraping.html import HTMLSource
 
 
@@ -22,6 +22,7 @@ async def scrape(
  self,
  error_handling: Literal["suppress", "catch", "raise"],
  extraction_filter: Optional[ExtractionFilter] = None,
+ url_filter: Optional[URLFilter] = None,
  ) -> AsyncIterator[Optional[Article]]:
  # TODO: add docstring; especially explain why returned Article is Optional
  if isinstance(extraction_filter, Requires):
@@ -43,7 +44,7 @@ async def scrape(
  return
 
  for html_source in self.sources:
- async for html in html_source.fetch():
+ async for html in html_source.fetch(url_filter=url_filter):
  if html is None:
  yield None
  continue