通过覆盖 CrawlSpider init() 方法实现 scrapy 规则

Question

我正在尝试覆盖 CrawlSpider 的 init() 方法，以便能够传递域名和起始页。不过，我好像没法把规则传进去。

我已经尝试了这里建议的方法（），并在 super() 方法之前定义了规则，但它似乎不起作用。

这是我的蜘蛛：

import scrapy
from scrapy.linkextractors import LinkExtractor
from scrapy.spiders import CrawlSpider, Rule

class SomeSpider(CrawlSpider):
    name = 'some_s'


    def __init__(self, *args, **kwargs):
        self.allowed_domains = kwargs.get('FIRST_DOMAIN')[1:-1]
        self.start_urls = [kwargs.get('FIRST_PAGE')[1:-1]]
        self.rules = (
            Rule(LinkExtractor(), callback='parse_item', follow=True),
        )

        super(SomeSpider, self).__init__(*args, **kwargs)

    def parse_item(self, response):
        i = {}
        i['url'] = response.url
        return i

我将这些值传递给终端，但它停在第一页：

$scrapy crawl some_s -a FIRST_PAGE='https://www.wikipedia.org/' -a FIRST_DOMAIN='wikipedia.org'

这是日志：

2018-11-10 14:07:26 [scrapy.utils.log] INFO: Scrapy 1.5.1 started (bot: foo)
2018-11-10 14:07:26 [scrapy.utils.log] INFO: Versions: lxml 4.2.5.0, libxml2 2.9.5, cssselect 1.0.3, parsel 1.5.0, w3lib 1.19.0, Twisted 18.9.0, Python 3.7.0 (v3.7.0:1bf9cc5093, Jun 27 2018, 04:06:47) [MSC v.1914 32 bit (Intel)], pyOpenSSL 18.0.0 (OpenSSL 1.1.0i  14 Aug 2018), cryptography 2.3.1, Platform Windows-10-10.0.17134-SP0
2018-11-10 14:07:26 [scrapy.crawler] INFO: Overridden settings: {'BOT_NAME': 'foo', 'NEWSPIDER_MODULE': 'foo.spiders', 'SPIDER_MODULES': ['foo.spiders'], 'USER_AGENT': 'Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:63.0) Gecko/20100101 Firefox/63.0'}
2018-11-10 14:07:26 [scrapy.middleware] INFO: Enabled extensions:
['scrapy.extensions.corestats.CoreStats',
 'scrapy.extensions.telnet.TelnetConsole',
 'scrapy.extensions.logstats.LogStats']
2018-11-10 14:07:26 [scrapy.middleware] INFO: Enabled downloader middlewares:
['scrapy.downloadermiddlewares.httpauth.HttpAuthMiddleware',
 'scrapy.downloadermiddlewares.downloadtimeout.DownloadTimeoutMiddleware',
 'scrapy.downloadermiddlewares.defaultheaders.DefaultHeadersMiddleware',
 'scrapy.downloadermiddlewares.useragent.UserAgentMiddleware',
 'foo.middlewares.FooDownloaderMiddleware',
 'scrapy.downloadermiddlewares.retry.RetryMiddleware',
 'scrapy.downloadermiddlewares.redirect.MetaRefreshMiddleware',
 'scrapy.downloadermiddlewares.httpcompression.HttpCompressionMiddleware',
 'scrapy.downloadermiddlewares.redirect.RedirectMiddleware',
 'scrapy.downloadermiddlewares.cookies.CookiesMiddleware',
 'scrapy.downloadermiddlewares.httpproxy.HttpProxyMiddleware',
 'scrapy.downloadermiddlewares.stats.DownloaderStats']
2018-11-10 14:07:26 [scrapy.middleware] INFO: Enabled spider middlewares:
['scrapy.spidermiddlewares.httperror.HttpErrorMiddleware',
 'scrapy.spidermiddlewares.offsite.OffsiteMiddleware',
 'scrapy.spidermiddlewares.referer.RefererMiddleware',
 'scrapy.spidermiddlewares.urllength.UrlLengthMiddleware',
 'scrapy.spidermiddlewares.depth.DepthMiddleware']
2018-11-10 14:07:26 [scrapy.middleware] INFO: Enabled item pipelines:
['foo.pipelines.FooPipeline']
2018-11-10 14:07:26 [scrapy.core.engine] INFO: Spider opened
2018-11-10 14:07:26 [scrapy.extensions.logstats] INFO: Crawled 0 pages (at 0 pages/min), scraped 0 items (at 0 items/min)
2018-11-10 14:07:26 [some_s] INFO: Spider opened: some_s
2018-11-10 14:07:26 [scrapy.extensions.telnet] DEBUG: Telnet console listening on 127.0.0.1:6023
2018-11-10 14:07:27 [scrapy.core.engine] DEBUG: Crawled (200) <GET https://www.wikipedia.org/> (referer: None)
2018-11-10 14:07:27 [scrapy.spidermiddlewares.offsite] DEBUG: Filtered offsite request to 'en.wikipedia.org': <GET https://en.wikipedia.org/>
.
.
.
2018-11-10 14:07:27 [scrapy.spidermiddlewares.offsite] DEBUG: Filtered offsite request to 'creativecommons.org': <GET https://creativecommons.org/licenses/by-sa/3.0/>
2018-11-10 14:07:27 [scrapy.core.engine] INFO: Closing spider (finished)
2018-11-10 14:07:27 [scrapy.statscollectors] INFO: Dumping Scrapy stats:
{'downloader/request_bytes': 260,
 'downloader/request_count': 1,
 'downloader/request_method_count/GET': 1,
 'downloader/response_bytes': 19485,
 'downloader/response_count': 1,
 'downloader/response_status_count/200': 1,
 'finish_reason': 'finished',
 'finish_time': datetime.datetime(2018, 11, 10, 13, 7, 27, 704476),
 'log_count/DEBUG': 298,
 'log_count/INFO': 8,
 'offsite/domains': 296,
 'offsite/filtered': 310,
 'request_depth_max': 1,
 'response_received_count': 1,
 'scheduler/dequeued': 1,
 'scheduler/dequeued/memory': 1,
 'scheduler/enqueued': 1,
 'scheduler/enqueued/memory': 1,
 'start_time': datetime.datetime(2018, 11, 10, 13, 7, 26, 767970)}
2018-11-10 14:07:27 [scrapy.core.engine] INFO: Spider closed (finished)

Answer 1

您的 allowed_domains 可能有问题，请确保它是一个格式正确的列表。如果我尝试这个，它工作正常：

from scrapy.linkextractors import LinkExtractor
from scrapy.spiders import CrawlSpider, Rule

class AnimeSpider(CrawlSpider):

    name = "Anime"

    def __init__(self, *args, **kwargs):
        self.allowed_domains = ['myanimelist.net']
        self.start_urls = ['https://myanimelist.net/anime.php']
        self.rules = (
            Rule(LinkExtractor(), callback='parse_item', follow=True),
        )

        super(AnimeSpider, self).__init__(*args, **kwargs)

    def parse_item(self, response):
        yield {
            'url': response.url
        }

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