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python - Scrapy 提前停止，没有错误

问题描述

所以我试图用大约 2000 页的帖子抓取一个博客，但 scrapy 似乎提前完成并且没有到达最后一页。

import scrapy


class postsSpider(scrapy.Spider):
    name = "posts"

    # URL's to scrape.
    start_urls = [
        "Removed for privacy"
    ]

    def parse(self, response):
        # Calls postDetails Parser.
        post_urls = response.css(
            "div.article-inner > header > h2 > a::attr(href)").extract()
        for url in post_urls:
            post_urls = response.urljoin(url)
            yield scrapy.Request(url=post_urls, callback=self.parsePostDetails)

        # Handles next pages.
        next_page = response.css(
            "#main > nav > div > a.next.page-numbers::attr(href)").extract_first()
        if next_page is not None:
            yield response.follow(next_page, callback=self.parse)

    # Parses each post for its title, postBody, and postDate.
    def parsePostDetails(self, response):
        postString = response.css(
            "div.article-inner > div.entry-content > p::text").extract()
        postTitle = response.css(
            "div.article-inner > header > h1::text").extract()
        postAuth = response.css(
            """div.article-inner > header > div.entry-meta.aftertitle-meta > span.author.vcard
> a > em::text""").extract()
        postTime = response.css(
            "div.article-inner > header > div.entry-meta.aftertitle-meta > span.onDate.date > time.published::text").extract()
        yield {
            'postTitle': str(postTitle),
            'postBody': str(postString),
            'postAuthor': str(postAuth),
            'postDate': str(postTime)
        }

2019-01-08 14:04:53 [scrapy.core.engine] INFO: Closing spider (finished)
2019-01-08 14:04:53 [scrapy.extensions.feedexport] INFO: Stored json feed (600 items) in: posts5.json
2019-01-08 14:04:53 [scrapy.statscollectors] INFO: Dumping Scrapy stats:
{'downloader/request_bytes': 242774,
 'downloader/request_count': 641,
 'downloader/request_method_count/GET': 641,
 'downloader/response_bytes': 58016154,
 'downloader/response_count': 641,
 'downloader/response_status_count/200': 641,
 'finish_reason': 'finished',
 'finish_time': datetime.datetime(2019, 1, 8, 19, 4, 53, 583047),
 'item_scraped_count': 600,
 'log_count/DEBUG': 1242,
 'log_count/INFO': 10,
 'request_depth_max': 40,
 'response_received_count': 641,
 'scheduler/dequeued': 640,
 'scheduler/dequeued/memory': 640,
 'scheduler/enqueued': 640,
 'scheduler/enqueued/memory': 640,
 'start_time': datetime.datetime(2019, 1, 8, 19, 2, 51, 782255)}
2019-01-08 14:04:53 [scrapy.core.engine] INFO: Spider closed (finished)

我不太确定是什么原因造成的。它似乎停在随机点。知道为什么会这样吗？我认为它与分页有关，但我无法弄清楚发生了什么。

标签： pythonpaginationscrapyweb-crawler

解决方案

您的蜘蛛很可能只是找不到下一页：

# Handles next pages.
next_page = response.css(
    "#main > nav > div > a.next.page-numbers::attr(href)").extract_first()
if next_page is not None:
    yield response.follow(next_page, callback=self.parse)

尝试添加：

else:
    from scrapy.shell import inspect_response
    inspect_response(response, self)

这将打开scrapy debug shell，您可以实时与对象交互：

# open webpage in browser
>>> view(response)

似乎您的下一页 css 在这里可能有点过度设计，一些 html 不一致可能会破坏它。试一试a.next.page-numbers::attr(href)

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