非命令行运行Scrapy脚本失败求助（附代码及报错）

尝试按官方文档方式直接运行Scrapy脚本（不用scrapy crawl命令），但脚本报错无法加载HTTPDownloadHandler，核心报错如下，完整报错未全部粘贴：

我的代码 #

import scrapy
from scrapy.crawler import CrawlerProcess

class misbeneficiosSpider(scrapy.Spider):
    name = 'misbeneficios'
    start_urls = ['https://productos.misbeneficios.com.uy/tv-y-audio',
                  'https://productos.misbeneficios.com.uy/tv-y-audio?p=2']

    def parse(self, response):
        for products in response.css('div.product-item-info'):
            yield {
                'name': products.css('a.product-item-link::text').get(),
                'price': products.css('span.price::text').get().replace('U$S\xa0', '')#[:-3].upper()
            }
        next_page = response.css('a.action.next').attrib['href']
        if next_page is not None:
            yield response.follow(next_page, callback=self.parse)

process = CrawlerProcess(settings={
    "FEEDS": {
        "items.csv": {"format": "csv"},
    },
})

process.crawl(misbeneficiosSpider)
process.start()

报错信息 #

2022-11-09 00:02:08 [scrapy.utils.log] INFO: Scrapy 2.7.1 started (bot: scrapybot)
2022-11-09 00:02:08 [scrapy.utils.log] INFO: Versions: lxml 4.9.1.0, libxml2 2.9.12, cssselect 1.2.0, parsel 1.7.0, w3lib 2.0.1, Twisted 22.10.0, Python 3.8.5 (tags/v3.8.5:580fbb0, Jul 20 2020, 15:43:08) [MSC v.1926 32 bit (Intel)], pyOpenSSL 22.1.0 (OpenSSL 3.0.7 1 Nov 2022), cryptography 38.0.3, Platform Windows-10-10.0.22000-SP0
2022-11-09 00:02:08 [scrapy.crawler] INFO: Overridden settings:
{}
2022-11-09 00:02:08 [py.warnings] WARNING: C:\Users\cabre\AppData\Local\Programs\Python\Python38-32\lib\site-packages\scrapy\utils\request.py:231: ScrapyDeprecationWarning: '2.6' is a deprecated value for the 'REQUEST_FINGERPRINTER_IMPLEMENTATION' setting.

It is also the default value. In other words, it is normal to get this warning if you have not defined a value for the 'REQUEST_FINGERPRINTER_IMPLEMENTATION' setting. This is so for backward compatibility reasons, but it will change in a future version of Scrapy.

See the documentation of the 'REQUEST_FINGERPRINTER_IMPLEMENTATION' setting for information on how to handle this deprecation.
  return cls(crawler)

2022-11-09 00:02:08 [scrapy.utils.log] DEBUG: Using reactor: twisted.internet.selectreactor.SelectReactor
2022-11-09 00:02:08 [scrapy.extensions.telnet] INFO: Telnet Password: 034a39dcf0704cf3
2022-11-09 00:02:08 [scrapy.middleware] INFO: Enabled extensions:
['scrapy.extensions.corestats.CoreStats',
 'scrapy.extensions.telnet.TelnetConsole',
 'scrapy.extensions.feedexport.FeedExporter',
 'scrapy.extensions.logstats.LogStats']
2022-11-09 00:02:09 [scrapy.core.downloader.handlers] ERROR: Loading "scrapy.core.downloader.handlers.http.HTTPDownloadHandler" for scheme "http"

解决方案 #

1. 解决HTTPDownloadHandler加载失败问题 #

报错核心是Twisted 22.10.0与Scrapy 2.7.1在32位Python环境下存在兼容性问题，执行以下命令降级Twisted：

pip install twisted==22.8.0

若问题仍存在，建议切换到64位Python环境，32位Python对部分Scrapy依赖的支持有限。

2. 修复代码中的潜在异常 #

原代码直接通过attrib['href']获取下一页链接，若页面无下一页元素会抛出KeyError；同时price字段未处理None值情况，修改为安全获取方式：

• 下一页链接：用::attr(href)结合get()方法获取
• 价格字段：先判断是否为None再处理

3. 消除DeprecationWarning #

在CrawlerProcess的settings中添加REQUEST_FINGERPRINTER_IMPLEMENTATION配置，指定当前兼容的版本。

修改后的完整代码 #

import scrapy
from scrapy.crawler import CrawlerProcess

class misbeneficiosSpider(scrapy.Spider):
    name = 'misbeneficios'
    start_urls = ['https://productos.misbeneficios.com.uy/tv-y-audio',
                  'https://productos.misbeneficios.com.uy/tv-y-audio?p=2']

    def parse(self, response):
        for products in response.css('div.product-item-info'):
            price_text = products.css('span.price::text').get()
            yield {
                'name': products.css('a.product-item-link::text').get(),
                'price': price_text.replace('U$S\xa0', '') if price_text else None
            }
        # 安全获取下一页链接
        next_page = response.css('a.action.next::attr(href)').get()
        if next_page is not None:
            yield response.follow(next_page, callback=self.parse)

process = CrawlerProcess(settings={
    "FEEDS": {
        "items.csv": {"format": "csv"},
    },
    "REQUEST_FINGERPRINTER_IMPLEMENTATION": "2.7",
})

process.crawl(misbeneficiosSpider)
process.start()

内容的提问来源于stack exchange，提问作者Bruno123