python - Scrapy 蜘蛛不跟踪链接和错误

Question

我正在尝试使用 scrapy 编写我的第一个网络爬虫/数据提取器，但无法通过链接获取它。我也收到一个错误:

ERROR: Spider error processing < GET https://en.wikipedia.org/wiki/Wikipedia:Unusual_articles>

我知道蜘蛛正在扫描页面一次，因为我能够从我弄乱的 a 标签和 h1 元素中提取信息。

有谁知道我怎样才能使它跟随页面上的链接并消除错误？

import scrapy
from scrapy.linkextractors import LinkExtractor
from wikiCrawler.items import WikicrawlerItem
from scrapy.spiders import Rule


class WikispyderSpider(scrapy.Spider):
    name = "wikiSpyder"

    allowed_domains = ['https://en.wikipedia.org/']

    start_urls = ['https://en.wikipedia.org/wiki/Wikipedia:Unusual_articles']

    rules = (
        Rule(LinkExtractor(canonicalize=True, unique=True), follow=True, callback="parse"),
    )

    def start_requests(self):
        for url in self.start_urls:
            yield scrapy.Request(url, callback=self.parse, dont_filter=True)

    def parse(self, response):
        items = []
        links = LinkExtractor(canonicalize=True, unique=True).extract_links(response)
        for link in links:
            item = WikicrawlerItem()
            item['url_from'] = response.url
            item['url_to'] = link.url
            items.append(item)
            print(items)
        return items

Answer 1

如果你想使用链接提取器，你需要使用一个特殊的蜘蛛类 - CrawlSpider :

from scrapy.spiders import CrawlSpider

class WikispyderSpider(CrawlSpider):
    # ...

这是一个简单的蜘蛛程序，它跟踪您的起始 url 中的链接并打印出页面标题:

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

from scrapy.spiders import Rule


class WikispyderSpider(CrawlSpider):
    name = "wikiSpyder"

    allowed_domains = ['en.wikipedia.org']
    start_urls = ['https://en.wikipedia.org/wiki/Wikipedia:Unusual_articles']

    rules = (
        Rule(LinkExtractor(canonicalize=True, unique=True), follow=True, callback="parse_link"),
    )

    def parse_link(self, response):
        print(response.xpath("//title/text()").extract_first())