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