scrapy - 如何为不同的蜘蛛设置不同的scrapy-settings？

Question

我想为某些蜘蛛启用一些 http-proxy，并为其他蜘蛛禁用它们。

我可以做这样的事情吗？

# 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 版以来，scrapy 中有一个新功能，您可以在其中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然后在要启用代理的蜘蛛中定义属性。不要忘记禁用默认代理中间件并启用您修改过的中间件。

Answer 5

为什么不使用两个项目而不仅仅是一个？

proj1让我们用和命名这两个项目proj2。在proj1'ssettings.py中，输入以下设置：

HTTP_PROXY = 'http://127.0.0.1:8123'
DOWNLOADER_MIDDLEWARES = {
     'myproject.middlewares.RandomUserAgentMiddleware': 400,
     'myproject.middlewares.ProxyMiddleware': 410,
     'scrapy.contrib.downloadermiddleware.useragent.UserAgentMiddleware': None
}

在proj2'ssettings.py中，输入以下设置：

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