错误：Scrapy 模块中的蜘蛛错误处理

Question

我使用scrapy 编写了一个网络抓取程序，它从搜索结果中提取标题和正文，并在使用命令运行蜘蛛时

scrapy crawl reddit

它显示

调试：已爬网 (200) https://www.reddit.com/r/help/search?q=hydrochlorothiazide/>（推荐人： 无）

ERROR：蜘蛛错误处理 https://www.reddit.com/r/help/search?q=hydrochlorothiazide/>（推荐人： 无）

但是，如果我在一个scrapy shell 中一一运行这些命令，它就会被正确地抓取。有人可以帮我解决这个问题吗？

import scrapy

class RedditSpider(scrapy.Spider):
    name = 'reddit'
    allowed_domains = ['www.reddit.com']
    start_urls = ['https://www.reddit.com/r/help/search?q=hydrochlorothiazide/']

    def parse(self, response):
        #view(self.response)
        posts = response.xpath('//*[@class="search-result-group"]')
        for post in posts:
            header = post.xpath('//*[@class="search-result-header"]/a/text()').extract_first()
            text = post.xpath('//*[@class="md"]/p/text()').extract_first()
            yield{'Header':header,'Text':text}

Answer 1

您使用的是哪个版本的scrapy？ 将其升级到最新版本 (1.5.0)。

创建空的虚拟环境并安装scrapy：

projects > $ virtualenv --no-site-packages --python=python3.5 venv
...
Installing setuptools, pkg_resources, pip, wheel...done.
projects > $ source venv/bin/activate
[3.5.5](venv) projects > $ pip freeze
pkg-resources==0.0.0
[3.5.5](venv) projects > $ pip install scrapy
...
Successfully installed Automat-0.6.0 PyDispatcher-2.0.5 Twisted-18.4.0
asn1crypto-0.24.0 attrs-18.1.0 cffi-1.11.5 constantly-15.1.0     
cryptography-2.2.2 cssselect-1.0.3 hyperlink-18.0.0 idna-2.6 
incremental-17.5.0 lxml-4.2.1 parsel-1.4.0 pyOpenSSL-17.5.0 pyasn1-0.4.2 
pyasn1-modules-0.2.1 pycparser-2.18 queuelib-1.5.0 scrapy-1.5.0 
service-identity-17.0.0 six-1.11.0 w3lib-1.19.0 zope.interface-4.5.0
[3.5.5](venv) projects > $ pip freeze
asn1crypto==0.24.0
attrs==18.1.0
Automat==0.6.0
cffi==1.11.5
constantly==15.1.0
cryptography==2.2.2
cssselect==1.0.3
hyperlink==18.0.0
idna==2.6
incremental==17.5.0
lxml==4.2.1
parsel==1.4.0
pkg-resources==0.0.0
pyasn1==0.4.2
pyasn1-modules==0.2.1
pycparser==2.18
PyDispatcher==2.0.5
pyOpenSSL==17.5.0
queuelib==1.5.0
Scrapy==1.5.0
service-identity==17.0.0
six==1.11.0
Twisted==18.4.0
w3lib==1.19.0
zope.interface==4.5.0

制作scrapy项目并编写你的蜘蛛：

[3.5.5](venv) projects > $ scrapy startproject reddit
[3.5.5](venv) projects > $ cd reddit/reddit/spiders/
[3.5.5](venv) spiders > $ touch spider.py && subl spider.py

spider.py：

import scrapy

class RedditSpider(scrapy.Spider):
    name = 'reddit'
    allowed_domains = ['www.reddit.com']
    start_urls = ['https://www.reddit.com/r/help/search?q=hydrochlorothiazide/']

    def parse(self, response):
        #view(self.response)
        posts = response.xpath('//*[@class="contents"]/div')
        for post in posts:
            header = post.xpath('.//*[@class="search-result-header"]/a/text()').extract_first()
            text = '\n'.join(post.xpath('.//*[@class="md"]/p/text()').extract())
            yield{'Header':header,'Text':text}

启动爬虫：

[3.5.5](venv) spiders > $ scrapy crawl reddit
...
[scrapy.core.engine] INFO: Spider opened
[scrapy.extensions.logstats] INFO: Crawled 0 pages (at 0 pages/min), scraped 0 items (at 0 items/min)
[scrapy.extensions.telnet] DEBUG: Telnet console listening on 127.0.0.1:6023
[scrapy.core.engine] DEBUG: Crawled (200) <GET https://www.reddit.com/robots.txt> (referer: None)
[scrapy.core.engine] DEBUG: Crawled (200) <GET https://www.reddit.com/r/help/search?q=hydrochlorothiazide/> (referer: None)
[scrapy.core.scraper] DEBUG: Scraped from <200 https://www.reddit.com/r/help/search?q=hydrochlorothiazide/>
...
{'Text': '', 'Header': 'Human medicines European public assessment report (EPAR): Irbesartan Hydrochlorothiazide Zentiva (previously Irbesartan Hydrochlorothiazide Winthrop), irbesartan / hydrochlorothiazide, Revision: 18, Authorised'}
[scrapy.core.scraper] DEBUG: Scraped from <200 https://www.reddit.com/r/help/search?q=hydrochlorothiazide/>
{'Text': '', 'Header': 'Human medicines European public assessment report (EPAR): Irbesartan/Hydrochlorothiazide Teva, irbesartan / hydrochlorothiazide, Revision: 6, Authorised'}
[scrapy.core.scraper] DEBUG: Scraped from <200 https://www.reddit.com/r/help/search?q=hydrochlorothiazide/>
{'Text': '', 'Header': 'Human medicines European public assessment report (EPAR): MicardisPlus, telmisartan / hydrochlorothiazide, Revision: 22, Authorised'}
[scrapy.core.engine] INFO: Closing spider (finished)
[scrapy.statscollectors] INFO: Dumping Scrapy stats:
{'downloader/request_bytes': 511,
 'downloader/request_count': 2,
 'downloader/request_method_count/GET': 2,
 'downloader/response_bytes': 28254,
 'downloader/response_count': 2,
 'downloader/response_status_count/200': 2,
 'finish_reason': 'finished',
 'item_scraped_count': 22,
 'log_count/DEBUG': 25,
 'log_count/INFO': 7,
 'memusage/max': 53526528,
 'memusage/startup': 53526528,
 'response_received_count': 2,
 'scheduler/dequeued': 1,
 'scheduler/dequeued/memory': 1,
 'scheduler/enqueued': 1,
 'scheduler/enqueued/memory': 1}
[scrapy.core.engine] INFO: Spider closed (finished)