On force-stop (second Ctrl+C), cancel_scope.cancel() was called BEFORE
_save_checkpoint(). Since cancel_scope.cancel() causes all subsequent
awaits within the scope to raise Cancelled, the checkpoint write was
silently aborted:
1. _save_checkpoint() uses anyio.open_file + rename — both are await
checkpoints that get cancelled immediately
2. self.paused never gets set to True (code after the aborted save)
3. The finally block sees 'not self.paused' and calls cleanup() which
DELETES the previous checkpoint file
Result: a user who ran a long crawl, pressed Ctrl+C twice to force-stop,
loses their entire checkpoint irrecoverably. The old checkpoint (from
periodic saves or a previous graceful pause) is deleted, and the new
one was never written.
Fix: move the cancel_scope.cancel() call AFTER the checkpoint save.
The save completes normally, self.paused is set to True, and only then
does the scope get cancelled to abort in-flight tasks. The finally
block correctly sees paused=True and skips cleanup.
Adds 6 regression tests covering:
- Force-stop checkpoint preservation (core regression)
- Graceful pause still works
- Force-stop checkpoint is loadable
- Normal completion cleanup still works
- Force-stop without checkpoint system
- Existing checkpoint not deleted on force-stop
Stop using allowed_domains for robots.txt prefetch since bare domain strings have no scheme info.
Domains discovered mid-crawl via requests still fetch robots.txt lazily.
Previously robots.txt was fetched lazily on the first request per
domain, causing early concurrent requests to each stall waiting for
the same network fetch. The cache is now warmed before the crawl loop
starts, making all subsequent robots.txt lookups a local read.
- RobotsTxtManager gains a prefetch(urls, sid) method that fetches all domains concurrently via a task group
- CrawlerEngine._prefetch_robots_txt() is called after on_start():
uses allowed_domains if configured, otherwise falls back to unique
domains extracted from start_urls
- Mid-crawl domain discovery (not covered by prefetch) still fetches
lazily; two concurrent callbacks on the same new domain can each
trigger a fetch — accepted tradeoff, documented in _get_domain_delay
Files: scrapling/spiders/robotstxt.py, scrapling/spiders/engine.py, tests/spiders/test_engine.py
When _checkpoint_system_enabled is False, the method uses a bare
`raise` with no active exception, which causes RuntimeError at
runtime. The method's docstring says it returns False when restoration
is not possible, so return False is the correct behavior.
The caller in crawl() currently guards with `if
self._checkpoint_system_enabled`, but the method's own contract
should be self-consistent.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
- A modern spider design that uses AnyIO and asyncio, yet it's very similar to Scrapy spiders API because it's the easiest design for users, and to make it easier for new users.
- Spiders can have multiple sessions per crawl, and users decide which session to use with each request.
- A scheduler system that uses heapq logic.
- The user can set the number of concurrent requests for a spider globally or per domain.
- The user can set a download delay to control the speed of the spider more.
- There's a global function that can be overridden to handle errors for all requests. (Similar to errback in scrapy).
- There's a spider argument to set the allowed domains for the spider to stay in.
- Each spider has a very detailed crawl stats that can be accessed right away from the code after the crawl finishes. Same case with scraped items.
- The whole spider as written as any other script and you just run it. No command-line arguments, and no need to run it from the terminal through the library like other known alternatives.
- Each spider has its own logger that forces sessions to use it.
- Each spider has functions to override that run before start and after close.
- There's a spider argument to set the logging level and another one to make the spider write to a log file.
- This is only the start. A lot more features are coming in the way.
Karim shoair