如何通过文件管道使用Python / Scrapy下载（PDF）文件？

Question

在Windows 10上使用Python 3.7.2，我正在努力让Scrapy v1.5.1下载一些PDF文件。 我关注了文档，但似乎错过了一些东西。 Scrapy为我提供了所需的PDF URL， 但未下载任何内容 。 也不会引发任何错误（至少）。

相关代码为：

scrapy.cfg：

[settings]
default = pranger.settings

[deploy]
project = pranger

settings.py：

BOT_NAME = 'pranger'

SPIDER_MODULES = ['pranger.spiders']
NEWSPIDER_MODULE = 'pranger.spiders'

ROBOTSTXT_OBEY = True

ITEM_PIPELINES = {
    'pranger.pipelines.PrangerPipeline': 300,
    'scrapy.pipelines.files.FilesPipeline': 1,
}

FILES_STORE = r'C:\pranger_downloaded'

FILES_URLS_FIELD = 'PDF_urls'
FILES_RESULT_FIELD = 'processed_PDFs'

pranger_spider.py：

import scrapy

class IndexSpider(scrapy.Spider):
    name = "index"
    url_liste = []

    def start_requests(self):
        urls = [
            'http://verbraucherinfo.ua-bw.de/lmk.asp?ref=3',
        ]
        for url in urls:
            yield scrapy.Request(url=url, callback=self.parse)

    def parse(self, response):
        for menupunkt in response.css('div#aufklappmenue'):
            yield {
                'file_urls': menupunkt.css('div.aussen a.innen::attr(href)').getall()
            }

items.py：

import scrapy    

class PrangerItem(scrapy.Item):
    file_urls = scrapy.Field()
    files = scrapy.Field()

所有其他文件均与scrapy startproject命令创建的scrapy startproject 。
scrapy crawl index的输出为：

(pranger) C:\pranger>scrapy crawl index
2019-02-20 15:45:18 [scrapy.utils.log] INFO: Scrapy 1.5.1 started (bot: pranger)
2019-02-20 15:45:18 [scrapy.utils.log] INFO: Versions: lxml 4.3.1.0, libxml2 2.9.9, cssselect 1.0.3, parsel 1.5.1, w3lib 1.20.0, Twisted 18.9.0, Python 3.7.2 (default, Feb 11 2019, 14:11:50) [MSC v.1915 64 bit (AMD64)], pyOpenSSL 19.0.0 (OpenSSL 1.1.1a  20 Nov 2018), cryptography 2.5, Platform Windows-10-10.0.17763-SP0
2019-02-20 15:45:18 [scrapy.crawler] INFO: Overridden settings: {'BOT_NAME': 'pranger', 'NEWSPIDER_MODULE': 'pranger.spiders', 'ROBOTSTXT_OBEY': True, 'SPIDER_MODULES': ['pranger.spiders']}
2019-02-20 15:45:18 [scrapy.middleware] INFO: Enabled extensions:
['scrapy.extensions.corestats.CoreStats',
 'scrapy.extensions.telnet.TelnetConsole',
 'scrapy.extensions.logstats.LogStats']
2019-02-20 15:45:18 [scrapy.middleware] INFO: Enabled downloader middlewares:
['scrapy.downloadermiddlewares.robotstxt.RobotsTxtMiddleware',
 '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']
2019-02-20 15:45:18 [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']
2019-02-20 15:45:18 [scrapy.middleware] INFO: Enabled item pipelines:
['scrapy.pipelines.files.FilesPipeline', 'pranger.pipelines.PrangerPipeline']
2019-02-20 15:45:18 [scrapy.core.engine] INFO: Spider opened
2019-02-20 15:45:18 [scrapy.extensions.logstats] INFO: Crawled 0 pages (at 0 pages/min), scraped 0 items (at 0 items/min)
2019-02-20 15:45:18 [scrapy.extensions.telnet] DEBUG: Telnet console listening on 127.0.0.1:6023
2019-02-20 15:45:19 [scrapy.core.engine] DEBUG: Crawled (404) <GET http://verbraucherinfo.ua-bw.de/robots.txt> (referer: None)
2019-02-20 15:45:19 [scrapy.core.engine] DEBUG: Crawled (200) <GET http://verbraucherinfo.ua-bw.de/lmk.asp?ref=3> (referer: None)
2019-02-20 15:45:19 [scrapy.core.scraper] DEBUG: Scraped from <200 http://verbraucherinfo.ua-bw.de/lmk.asp?ref=3>
{'file_urls': ['https://www.lrabb.de/site/LRA-BB-Desktop/get/params_E-428807985/3287025/Ergebnisse_amtlicher_Kontrollen_nach_LFGB_Landkreis_Boeblingen.pdf', <<...and dozens more URLs...>>], 'processed_PDFs': []}
2019-02-20 15:45:19 [scrapy.core.engine] INFO: Closing spider (finished)
2019-02-20 15:45:19 [scrapy.statscollectors] INFO: Dumping Scrapy stats:
{'downloader/request_bytes': 469,
 'downloader/request_count': 2,
 'downloader/request_method_count/GET': 2,
 'downloader/response_bytes': 13268,
 'downloader/response_count': 2,
 'downloader/response_status_count/200': 1,
 'downloader/response_status_count/404': 1,
 'finish_reason': 'finished',
 'finish_time': datetime.datetime(2019, 2, 20, 14, 45, 19, 166646),
 'item_scraped_count': 1,
 'log_count/DEBUG': 4,
 'log_count/INFO': 7,
 'response_received_count': 2,
 'scheduler/dequeued': 1,
 'scheduler/dequeued/memory': 1,
 'scheduler/enqueued': 1,
 'scheduler/enqueued/memory': 1,
 'start_time': datetime.datetime(2019, 2, 20, 14, 45, 18, 864509)}
2019-02-20 15:45:19 [scrapy.core.engine] INFO: Spider closed (finished)

哦，顺便说一句，我发布了代码，以防万一： https : //github.com/R0byn/pranger/tree/5bfa0df92f21cecee18cc618e9a8e7ceea192403

Answer 1

FILES_URLS_FIELD设置告诉管道项目的哪个字段包含要下载的URL。

默认情况下，它是file_urls ，但是如果您更改设置，则还需要更改用于存储URL的字段名称（键）。

因此，您有两个选择-使用默认设置，或将项目的字段也重命名为PDF_urls 。