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from __future__ import annotations
import pickle
from pathlib import Path
from typing import TYPE_CHECKING
from scrapy import Spider, signals
from scrapy.exceptions import NotConfigured
from scrapy.utils.job import job_dir
if TYPE_CHECKING:
# typing.Self requires Python 3.11
from typing_extensions import Self
from scrapy.crawler import Crawler
class SpiderState:
"""Store and load spider state during a scraping job"""
def __init__(self, jobdir: str | None = None):
self.jobdir: str | None = jobdir
@classmethod
def from_crawler(cls, crawler: Crawler) -> Self:
jobdir = job_dir(crawler.settings)
if not jobdir:
raise NotConfigured
obj = cls(jobdir)
crawler.signals.connect(obj.spider_closed, signal=signals.spider_closed)
crawler.signals.connect(obj.spider_opened, signal=signals.spider_opened)
return obj
def spider_closed(self, spider: Spider) -> None:
if self.jobdir:
with Path(self.statefn).open("wb") as f:
assert hasattr(spider, "state") # set in spider_opened
pickle.dump(spider.state, f, protocol=4)
def spider_opened(self, spider: Spider) -> None:
if self.jobdir and Path(self.statefn).exists():
with Path(self.statefn).open("rb") as f:
spider.state = pickle.load(f) # type: ignore[attr-defined] # noqa: S301
else:
spider.state = {} # type: ignore[attr-defined]
@property
def statefn(self) -> str:
assert self.jobdir
return str(Path(self.jobdir, "spider.state"))
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