mirror of https://github.com/scrapy/scrapy.git
38 lines
1.1 KiB
Python
38 lines
1.1 KiB
Python
"""Set User-Agent header per spider or use a default value from settings"""
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from __future__ import annotations
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from typing import TYPE_CHECKING
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from scrapy import Request, Spider, signals
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if TYPE_CHECKING:
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# typing.Self requires Python 3.11
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from typing_extensions import Self
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from scrapy.crawler import Crawler
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from scrapy.http import Response
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class UserAgentMiddleware:
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"""This middleware allows spiders to override the user_agent"""
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def __init__(self, user_agent: str = "Scrapy"):
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self.user_agent = user_agent
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@classmethod
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def from_crawler(cls, crawler: Crawler) -> Self:
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o = cls(crawler.settings["USER_AGENT"])
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crawler.signals.connect(o.spider_opened, signal=signals.spider_opened)
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return o
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def spider_opened(self, spider: Spider) -> None:
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self.user_agent = getattr(spider, "user_agent", self.user_agent)
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def process_request(
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self, request: Request, spider: Spider
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) -> Request | Response | None:
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if self.user_agent:
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request.headers.setdefault(b"User-Agent", self.user_agent)
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return None
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