"""Set User-Agent header per spider or use a default value from settings"""
from scrapy import signals
[docs]class UserAgentMiddleware:
"""This middleware allows spiders to override the user_agent"""
def __init__(self, user_agent="Scrapy"):
self.user_agent = user_agent
@classmethod
def from_crawler(cls, crawler):
o = cls(crawler.settings["USER_AGENT"])
crawler.signals.connect(o.spider_opened, signal=signals.spider_opened)
return o
def spider_opened(self, spider):
self.user_agent = getattr(spider, "user_agent", self.user_agent)
def process_request(self, request, spider):
if self.user_agent:
request.headers.setdefault(b"User-Agent", self.user_agent)