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"""
Base class for Scrapy spiders
See documentation in docs/topics/spiders.rst
"""
from __future__ import annotations
import logging
import warnings
from typing import TYPE_CHECKING, Any, cast
from scrapy import signals
from scrapy.exceptions import ScrapyDeprecationWarning
from scrapy.http import Request, Response
from scrapy.utils.trackref import object_ref
from scrapy.utils.url import url_is_from_spider
if TYPE_CHECKING:
from collections.abc import AsyncIterator, Iterable
from twisted.internet.defer import Deferred
# typing.Self requires Python 3.11
from typing_extensions import Self
from scrapy.crawler import Crawler
from scrapy.http.request import CallbackT
from scrapy.settings import BaseSettings, _SettingsKeyT
from scrapy.utils.log import SpiderLoggerAdapter
class Spider(object_ref):
"""Base class that any spider must subclass.
It provides a default :meth:`start` implementation that sends
requests based on the :attr:`start_urls` class attribute and calls the
:meth:`parse` method for each response.
"""
name: str
custom_settings: dict[_SettingsKeyT, Any] | None = None
#: Start URLs. See :meth:`start`.
start_urls: list[str]
def __init__(self, name: str | None = None, **kwargs: Any):
if name is not None:
self.name: str = name
elif not getattr(self, "name", None):
raise ValueError(f"{type(self).__name__} must have a name")
self.__dict__.update(kwargs)
if not hasattr(self, "start_urls"):
self.start_urls: list[str] = []
@property
def logger(self) -> SpiderLoggerAdapter:
from scrapy.utils.log import SpiderLoggerAdapter
logger = logging.getLogger(self.name)
return SpiderLoggerAdapter(logger, {"spider": self})
def log(self, message: Any, level: int = logging.DEBUG, **kw: Any) -> None:
"""Log the given message at the given log level
This helper wraps a log call to the logger within the spider, but you
can use it directly (e.g. Spider.logger.info('msg')) or use any other
Python logger too.
"""
self.logger.log(level, message, **kw)
@classmethod
def from_crawler(cls, crawler: Crawler, *args: Any, **kwargs: Any) -> Self:
spider = cls(*args, **kwargs)
spider._set_crawler(crawler)
return spider
def _set_crawler(self, crawler: Crawler) -> None:
self.crawler: Crawler = crawler
self.settings: BaseSettings = crawler.settings
crawler.signals.connect(self.close, signals.spider_closed)
async def start(self) -> AsyncIterator[Any]:
"""Yield the initial :class:`~scrapy.Request` objects to send.
.. versionadded:: 2.13
For example:
.. code-block:: python
from scrapy import Request, Spider
class MySpider(Spider):
name = "myspider"
async def start(self):
yield Request("https://toscrape.com/")
The default implementation reads URLs from :attr:`start_urls` and
yields a request for each with :attr:`~scrapy.Request.dont_filter`
enabled. It is functionally equivalent to:
.. code-block:: python
async def start(self):
for url in self.start_urls:
yield Request(url, dont_filter=True)
You can also yield :ref:`items <topics-items>`. For example:
.. code-block:: python
async def start(self):
yield {"foo": "bar"}
To write spiders that work on Scrapy versions lower than 2.13,
define also a synchronous ``start_requests()`` method that returns an
iterable. For example:
.. code-block:: python
def start_requests(self):
yield Request("https://toscrape.com/")
.. seealso:: :ref:`start-requests`
"""
with warnings.catch_warnings():
warnings.filterwarnings(
"ignore", category=ScrapyDeprecationWarning, module=r"^scrapy\.spiders$"
)
for item_or_request in self.start_requests():
yield item_or_request
def start_requests(self) -> Iterable[Any]:
warnings.warn(
(
"The Spider.start_requests() method is deprecated, use "
"Spider.start() instead. If you are calling "
"super().start_requests() from a Spider.start() override, "
"iterate super().start() instead."
),
ScrapyDeprecationWarning,
stacklevel=2,
)
if not self.start_urls and hasattr(self, "start_url"):
raise AttributeError(
"Crawling could not start: 'start_urls' not found "
"or empty (but found 'start_url' attribute instead, "
"did you miss an 's'?)"
)
for url in self.start_urls:
yield Request(url, dont_filter=True)
def _parse(self, response: Response, **kwargs: Any) -> Any:
return self.parse(response, **kwargs)
if TYPE_CHECKING:
parse: CallbackT
else:
def parse(self, response: Response, **kwargs: Any) -> Any:
raise NotImplementedError(
f"{self.__class__.__name__}.parse callback is not defined"
)
@classmethod
def update_settings(cls, settings: BaseSettings) -> None:
settings.setdict(cls.custom_settings or {}, priority="spider")
@classmethod
def handles_request(cls, request: Request) -> bool:
return url_is_from_spider(request.url, cls)
@staticmethod
def close(spider: Spider, reason: str) -> Deferred[None] | None:
closed = getattr(spider, "closed", None)
if callable(closed):
return cast("Deferred[None] | None", closed(reason))
return None
def __repr__(self) -> str:
return f"<{type(self).__name__} {self.name!r} at 0x{id(self):0x}>"
# Top-level imports
from scrapy.spiders.crawl import CrawlSpider, Rule
from scrapy.spiders.feed import CSVFeedSpider, XMLFeedSpider
from scrapy.spiders.sitemap import SitemapSpider
__all__ = [
"CSVFeedSpider",
"CrawlSpider",
"Rule",
"SitemapSpider",
"Spider",
"XMLFeedSpider",
]
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