Web scraping Scrapy运行但不'；t爬网站点-循环中的刮壳响应

我试着让Scrapy爬起来

问题是什么： 我写了一个Scraper，得到了200条回复，但没有结果-它刮了0页：

2020-09-06 12:42:00 [scrapy.utils.log] INFO: Scrapy 1.5.1 started (bot: stack)
2020-09-06 12:42:00 [scrapy.utils.log] INFO: Versions: lxml 4.2.5.0, libxml2 2.9.5, cssselect 1.0.3, parsel 1.5.1, w3lib 1.19.0, Twisted 18.9.0, Python 3.7.2 (tags/v3.7.2:9a3ffc0492, Dec 23 2018, 22:20:52) [MSC v.1916 32 bit (Intel)], pyOpenSSL 18.0.0 (OpenSSL 1.1.0j  20 Nov 2018), cryptography 2.4.2, Platform Windows-10-10.0.18362-SP0
2020-09-06 12:42:00 [scrapy.crawler] INFO: Overridden settings: {'BOT_NAME': 'stack', 'NEWSPIDER_MODULE': 'stack.spiders', 'SPIDER_MODULES': ['stack.spiders'], 'USER_AGENT': 'Mozilla/5.0 (Macintosh; Intel Mac OS X 10_12_6) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/61.0.3163.100 Safari/537.36'}
2020-09-06 12:42:00 [scrapy.middleware] INFO: Enabled extensions:
['scrapy.extensions.corestats.CoreStats',
 'scrapy.extensions.telnet.TelnetConsole',
 'scrapy.extensions.logstats.LogStats']
2020-09-06 12:42:01 [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']
2020-09-06 12:42:01 [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']
2020-09-06 12:42:01 [scrapy.middleware] INFO: Enabled item pipelines:
[]
2020-09-06 12:42:01 [scrapy.core.engine] INFO: Spider opened
2020-09-06 12:42:01 [scrapy.extensions.logstats] INFO: Crawled 0 pages (at 0 pages/min), scraped 0 items (at 0 items/min)
2020-09-06 12:42:01 [scrapy.extensions.telnet] DEBUG: Telnet console listening on 127.0.0.1:6023
2020-09-06 12:42:01 [scrapy.core.engine] DEBUG: Crawled (200) <GET https://www.beuth.de/de/regelwerke/vdi/vdi-richtlinien-entwuerfe> (referer: None)
2020-09-06 12:42:01 [scrapy.core.engine] INFO: Closing spider (finished)
2020-09-06 12:42:01 [scrapy.statscollectors] INFO: Dumping Scrapy stats:
{'downloader/request_bytes': 341,
 'downloader/request_count': 1,
 'downloader/request_method_count/GET': 1,
 'downloader/response_bytes': 6149,
 'downloader/response_count': 1,
 'downloader/response_status_count/200': 1,
 'downloader/request_method_count/GET': 1,
 'downloader/response_bytes': 6149,
 'downloader/response_count': 1,
 'downloader/response_status_count/200': 1,
 'finish_reason': 'finished',
 'finish_time': datetime.datetime(2020, 9, 6, 10, 42, 1, 684021),
 'log_count/DEBUG': 2,
 'log_count/INFO': 7,
 'response_received_count': 1,
 'scheduler/dequeued': 1,
 'scheduler/dequeued/memory': 1,
 'scheduler/enqueued': 1,
 'scheduler/enqueued/memory': 1,
 'start_time': datetime.datetime(2020, 9, 6, 10, 42, 1, 140686)}
2020-09-06 12:42:01 [scrapy.core.engine] INFO: Spider closed (finished)

这是我的爬虫程序代码：

from scrapy import Spider
from scrapy.selector import Selector

from stack.items import StackItem

class StackSpider(Spider):
    name = "stack"
    allowed_domains = ["www.beuth.de"]
    start_urls = [
        "https://www.beuth.de/de/regelwerke/vdi/vdi-richtlinien-entwuerfe",
    ]

    def parse(self, response):
        elements = Selector(response).xpath('//div[@class="bwr-card__inner"]')

        for element in elements:
            item = StackItem()
            item['title'] = element.xpath('a[@class="bwr-link__label"]/text()').extract()[0]
            item['url'] = element.xpath('a[@class="bwr-card__title-link"]/@href').extract()[0]
            item['date'] = element.xpath('div[@class="bwr-type__item bwr-type__item--light"]/text()').extract()[0]
            item['price'] = element.xpath('div[@class="bwr-buybox__price-emph]/text()').extract()[0]
            item['subtitle'] = element.xpath('div[@class="bwr-card__subtitle bwr-data-dlink"]/text()').extract()[0]
            item['description'] = element.xpath('div[@class="bwr-card__text bwr-rte bwr-data-dlink"]/text()').extract()[0]
            yield item

我尝试了什么来解决问题：

我试了一下这个粘乎乎的贝壳。在我使用定义的用户代理后，网站没有阻止我：

In[2]：来自碎屑导入请求 …：req=请求（“https://www.beuth.de/de/regelwerke/vdi/vdi-richtlinien-entwuerfe", headers={“用户代理”：“Mozi” …：lla/5.0（X11；Linux x86_64）AppleWebKit/537.36（KHTML，像Gecko）Chrome/58.0.3029.110 Safari/537.36 OPR/45.0。 ...: 2552.888"}) …：获取（请求）

---

2020-09-06 12:48:19[scrapy.core.engine]调试：爬网（200）您可以通过在shell中打印

response.body

来读取得到的响应。您将看到响应主要是一个javascript。有些页面使用这种类型的方法来防止爬虫，它们在加载页面之前检查浏览器是否可以执行JS（scrapy不能）。我不是说这是本页的案例，因为我只是快速浏览了一下。自己解析JS可能会让您更好地了解正在发生的事情。您可以通过在shell中打印

response.body

来读取得到的响应。您将看到响应主要是一个javascript。有些页面使用这种类型的方法来防止爬虫，它们在加载页面之前检查浏览器是否可以执行JS（scrapy不能）。我不是说这是本页的案例，因为我只是快速浏览了一下。自己解析JS可能会让您更好地了解正在发生的事情。

from scrapy import Spider
from scrapy.selector import Selector

from stack.items import StackItem

class StackSpider(Spider):
    name = "stack"
    allowed_domains = ["www.beuth.de"]
    start_urls = [
        "https://www.beuth.de/de/regelwerke/vdi/vdi-richtlinien-entwuerfe",
    ]

    def parse(self, response):
        elements = Selector(response).xpath('//div[@class="bwr-card__inner"]')

        for element in elements:
            item = StackItem()
            item['title'] = element.xpath('a[@class="bwr-link__label"]/text()').extract()[0]
            item['url'] = element.xpath('a[@class="bwr-card__title-link"]/@href').extract()[0]
            item['date'] = element.xpath('div[@class="bwr-type__item bwr-type__item--light"]/text()').extract()[0]
            item['price'] = element.xpath('div[@class="bwr-buybox__price-emph]/text()').extract()[0]
            item['subtitle'] = element.xpath('div[@class="bwr-card__subtitle bwr-data-dlink"]/text()').extract()[0]
            item['description'] = element.xpath('div[@class="bwr-card__text bwr-rte bwr-data-dlink"]/text()').extract()[0]
            yield item

In [3]: response.xpath("//div[@class='bwr-buybox__price']/a/text").getall()
Out[3]: []