解析回调未定义简单Webscraper（Scrapy）仍未运行

Question

我在谷歌上搜索了半天，还是没法继续。也许你有一些见解？你知道吗

我试着不是从终端开始，而是从脚本开始。 这在没有规则的情况下工作得很好，只需生成正常的解析函数。你知道吗

一旦我使用规则并将“callback=”parse“”更改为“callback=”parse\u item“”，就什么都不管用了。你知道吗

我试着创建一个爬虫程序，基于在我的解析函数中产生的请求。结果是：我只抓取了一个URL，但没有抓取域。你知道吗

有规则似乎是一条路要走。 所以我实际上希望它运行，而不是在parse函数中使用yields。你知道吗

import scrapy

from scrapy.crawler import CrawlerProcess
from bs4 import BeautifulSoup
from scrapy.http import Request
from scrapy.spiders import CrawlSpider, Rule
from scrapy.linkextractors import LinkExtractor


def beauty(response_dictionary):
    html_response = response_dictionary["html"]
    print(response_dictionary["url"])
    for html in html_response:
        soup = BeautifulSoup(html, 'lxml')
        metatag = soup.find_all("meta")
        print(metatag)

class MySpider(scrapy.Spider):
    name = "MySpidername"
    allowed_domains = ["www.bueffeln.net"]
    start_urls = ['https://www.bueffeln.net']

    rules = [Rule(LinkExtractor(allow=()), callback='parse_item', follow=True),]

    def parse_item(self, response):
        url_dictionary = {}
        print(response.status)
        url_dictionary["url"] = response.url
        print(response.headers)
        url_dictionary["html"] = response.xpath('//html').getall()
        beauty(url_dictionary)


process = CrawlerProcess({
    'USER_AGENT': 'Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 5.1)'
})

process.crawl(MySpider)
process.start() 

错误如下：

2019-11-18 18:14:56 [scrapy.utils.log] INFO: Scrapy 1.7.4 started (bot: scrapybot)
2019-11-18 18:14:56 [scrapy.utils.log] INFO: Versions: lxml 4.4.1.0, libxml2 2.9.5, cssselect 1.1.0, parsel 1.5.2, w3lib 1.21.0, Twisted 19.7.0, Python 3.7.4 (tags/v3.7.4:e09359112e, Jul  8 2019, 19:29:22) [MSC v.1916 32 bit (Intel)], pyOpenSSL 19.0.0 (OpenSSL 1.1.1d  10 Sep 2019), cryptography 2.8, Platform Windows-10-10.0.18362-SP0
2019-11-18 18:14:56 [scrapy.crawler] INFO: Overridden settings: {'USER_AGENT': 'Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 5.1)'}
2019-11-18 18:14:56 [scrapy.extensions.telnet] INFO: Telnet Password: 970cca12e7c43d67
2019-11-18 18:14:56 [scrapy.middleware] INFO: Enabled extensions:
['scrapy.extensions.corestats.CoreStats',
 'scrapy.extensions.telnet.TelnetConsole',
 'scrapy.extensions.logstats.LogStats']
2019-11-18 18:14:57 [scrapy.middleware] INFO: Enabled downloader middlewares:
['scrapy.downloadermiddlewares.httpauth.HttpAuthMiddleware',
 'scrapy.downloadermiddlewares.downloadtimeout.DownloadTimeoutMiddleware',
 'scrapy.downloadermiddlewares.defaultheaders.DefaultHeadersMiddleware',
 'scrapy.downloadermiddlewares.useragent.UserAgentMiddleware',
 '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']
2019-11-18 18:14:57 [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']
2019-11-18 18:14:57 [scrapy.middleware] INFO: Enabled item pipelines:
[]
2019-11-18 18:14:57 [scrapy.core.engine] INFO: Spider opened
2019-11-18 18:14:57 [scrapy.extensions.logstats] INFO: Crawled 0 pages (at 0 pages/min), scraped 0 items (at 0 items/min)
2019-11-18 18:14:57 [scrapy.extensions.telnet] INFO: Telnet console listening on 127.0.0.1:6023
2019-11-18 18:14:57 [scrapy.core.engine] DEBUG: Crawled (200) <GET https://www.bueffeln.net> (referer: None)
2019-11-18 18:14:57 [scrapy.core.scraper] ERROR: Spider error processing <GET https://www.bueffeln.net> (referer: None)
Traceback (most recent call last):
  File "C:\Users\msi\PycharmProjects\test\venv\lib\site-packages\twisted\internet\defer.py", line 654, in _runCallbacks
    current.result = callback(current.result, *args, **kw)
  File "C:\Users\msi\PycharmProjects\test\venv\lib\site-packages\scrapy\spiders\__init__.py", line 80, in parse
    raise NotImplementedError('{}.parse callback is not defined'.format(self.__class__.__name__))
NotImplementedError: MySpider.parse callback is not defined
2019-11-18 18:14:57 [scrapy.core.engine] INFO: Closing spider (finished)
2019-11-18 18:14:57 [scrapy.statscollectors] INFO: Dumping Scrapy stats:
{'downloader/request_bytes': 231,
 'downloader/request_count': 1,
 'downloader/request_method_count/GET': 1,
 'downloader/response_bytes': 16695,
 'downloader/response_count': 1,
 'downloader/response_status_count/200': 1,
 'elapsed_time_seconds': 0.435081,
 'finish_reason': 'finished',
 'finish_time': datetime.datetime(2019, 11, 18, 17, 14, 57, 454733),
 'log_count/DEBUG': 1,
 'log_count/ERROR': 1,
 'log_count/INFO': 10,
 'response_received_count': 1,
 'scheduler/dequeued': 1,
 'scheduler/dequeued/memory': 1,
 'scheduler/enqueued': 1,
 'scheduler/enqueued/memory': 1,
 'spider_exceptions/NotImplementedError': 1,
 'start_time': datetime.datetime(2019, 11, 18, 17, 14, 57, 19652)}
2019-11-18 18:14:57 [scrapy.core.engine] INFO: Spider closed (finished)

Process finished with exit code 0

Answer 1

Scrapy使用parse回调来解析来自start_urls的URL。你没有提供这样的回调，这就是为什么Scrapy不能处理你的https://www.bueffeln.netURL。你知道吗

如果希望代码正常工作，需要添加parse回调（甚至是空的）。您的rules将在parse回调后应用。你知道吗

更新 要使用规则，您需要scrapy.CrawlSpider：

class MySpider(scrapy.CrawlSpider):