如何为不同的蜘蛛设置不同的scrapy设置？

Question

我想为一些蜘蛛启用一些http代理,并为其他蜘蛛禁用它们.

我可以这样做吗？

# settings.py
proxy_spiders = ['a1' , b2']

if spider in proxy_spider: #how to get spider name ???
    HTTP_PROXY = 'http://127.0.0.1:8123'
    DOWNLOADER_MIDDLEWARES = {
         'myproject.middlewares.RandomUserAgentMiddleware': 400,
         'myproject.middlewares.ProxyMiddleware': 410,
         'scrapy.contrib.downloadermiddleware.useragent.UserAgentMiddleware': None
    }
else:
    DOWNLOADER_MIDDLEWARES = {
         'myproject.middlewares.RandomUserAgentMiddleware': 400,
         'scrapy.contrib.downloadermiddleware.useragent.UserAgentMiddleware': None
    }

如果上面的代码不起作用,还有其他建议吗？

Answer 1

有点晚了,但自1.0.0发布以来,scrapy中有一个新功能,你可以覆盖每个蜘蛛的设置,如下所示:

class MySpider(scrapy.Spider):
    name = "my_spider"
    custom_settings = {"HTTP_PROXY":'http://127.0.0.1:8123',
                       "DOWNLOADER_MIDDLEWARES": {'myproject.middlewares.RandomUserAgentMiddleware': 400,
                                                  'myproject.middlewares.ProxyMiddleware': 410,
                                                  'scrapy.contrib.downloadermiddleware.useragent.UserAgentMiddleware': None}}




class MySpider2(scrapy.Spider):
        name = "my_spider2"
        custom_settings = {"DOWNLOADER_MIDDLEWARES": {'myproject.middlewares.RandomUserAgentMiddleware': 400,
                                                      'scrapy.contrib.downloadermiddleware.useragent.UserAgentMiddleware': None}}

Answer 2

有一种新的更简单的方法可以做到这一点.

class MySpider(scrapy.Spider):
    name = 'myspider'

    custom_settings = {
        'SOME_SETTING': 'some value',
    }

我使用Scrapy 1.3.1

Answer 3

您可以在spider.py文件中添加setting.overrides有效的示例:

from scrapy.conf import settings

settings.overrides['DOWNLOAD_TIMEOUT'] = 300 

对你来说,这样的事情也应该有效

from scrapy.conf import settings

settings.overrides['DOWNLOADER_MIDDLEWARES'] = {
     'myproject.middlewares.RandomUserAgentMiddleware': 400,
     'scrapy.contrib.downloadermiddleware.useragent.UserAgentMiddleware': None
}

Answer 4

您可以定义自己的代理中间件，如下所示：

from scrapy.contrib.downloadermiddleware import HttpProxyMiddleware

class ConditionalProxyMiddleware(HttpProxyMiddleware):
    def process_request(self, request, spider):
        if getattr(spider, 'use_proxy', None):
            return super(ConditionalProxyMiddleware, self).process_request(request, spider)

use_proxy = True然后在蜘蛛中定义您想要启用代理的属性。不要忘记禁用默认代理中间件并启用您修改过的代理中间件。