问抓取-数据提取(如json)
EN

Stack Overflow用户

提问于 2018-03-17 21:07:02

回答 1查看 275关注 0票数 0

我试图通过使用刮除来废弃两个网页，但我没有得到预期的输出。还试图将数据提取为json文件，但输出文件为空。到目前为止，我已经尝试了下面提到的代码：

from plants.items import PlantsItem


class PlantsSpider(scrapy.Spider):
   name = "plants"
   allowed_domains = ["greatplantpicks.org"]


#Scraping web page

   start_urls = ["http://www.greatplantpicks.org/plantlists/by_plant_type/conifer"]


   def parse(self, response):

为了以json的形式获得输出，我使用了以下命令：

scrapy crawl plants -o trees_json.json

但是，除了下面提到的一些日志细节之外，我没有得到任何输出：

2018-03-18 04:47:29 [scrapy.utils.log] INFO: Scrapy 1.5.0 started (bot: plants)
2018-03-18 04:47:29 [scrapy.utils.log] INFO: Versions: lxml 4.2.0.0, libxml2 2.9.8, cssselect 1.0.3, parsel 1.4.0, w3lib 1.19.0, Twisted 17.9.0, Python 3.5.2 (default, Nov 23 2017, 16:37:01) - [GCC 5.4.0 20160609], pyOpenSSL 17.5.0 (OpenSSL 1.1.0g  2 Nov 2017), cryptography 2.1.4, Platform Linux-4.13.0-37-generic-x86_64-with-Ubuntu-16.04-xenial
2018-03-18 04:47:29 [scrapy.crawler] INFO: Overridden settings: {'BOT_NAME': 'plants', 'FEED_FORMAT': 'json', 'FEED_URI': 'trees_json.json', 'SPIDER_MODULES': ['plants.spiders'], 'NEWSPIDER_MODULE': 'plants.spiders', 'ROBOTSTXT_OBEY': True}
2018-03-18 04:47:29 [scrapy.middleware] INFO: Enabled extensions:
['scrapy.extensions.corestats.CoreStats',
 'scrapy.extensions.logstats.LogStats',
 'scrapy.extensions.memusage.MemoryUsage',
 'scrapy.extensions.telnet.TelnetConsole',
 'scrapy.extensions.feedexport.FeedExporter']
2018-03-18 04:47:29 [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']
2018-03-18 04:47:29 [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']
2018-03-18 04:47:29 [scrapy.middleware] INFO: Enabled item pipelines:
[]
2018-03-18 04:47:29 [scrapy.core.engine] INFO: Spider opened
2018-03-18 04:47:29 [scrapy.extensions.logstats] INFO: Crawled 0 pages (at 0 pages/min), scraped 0 items (at 0 items/min)
2018-03-18 04:47:29 [scrapy.extensions.telnet] DEBUG: Telnet console listening on 127.0.0.1:6023
2018-03-18 04:47:29 [scrapy.core.engine] DEBUG: Crawled (404) <GET http://www.greatplantpicks.org/robots.txt> (referer: None)
2018-03-18 04:47:30 [scrapy.core.engine] DEBUG: Crawled (200) <GET http://www.greatplantpicks.org/plantlists/by_plant_type/conifer> (referer: None)
2018-03-18 04:47:30 [scrapy.core.scraper] ERROR: Spider error processing <GET http://www.greatplantpicks.org/plantlists/by_plant_type/conifer> (referer: None)
Traceback (most recent call last):
  File "/home/mushfika/.local/lib/python3.5/site-packages/twisted/internet/defer.py", line 653, in _runCallbacks
    current.result = callback(current.result, *args, **kw)
  File "/home/mushfika/.local/lib/python3.5/site-packages/scrapy/spiders/__init__.py", line 90, in parse
    raise NotImplementedError('{}.parse callback is not defined'.format(self.__class__.__name__))
NotImplementedError: PlantsSpider.parse callback is not defined
2018-03-18 04:47:30 [scrapy.core.engine] INFO: Closing spider (finished)
2018-03-18 04:47:30 [scrapy.statscollectors] INFO: Dumping Scrapy stats:
{'downloader/request_bytes': 832,
 'downloader/request_count': 2,
 'downloader/request_method_count/GET': 2,
 'downloader/response_bytes': 61907,
 'downloader/response_count': 2,
 'downloader/response_status_count/200': 1,
 'downloader/response_status_count/404': 1,
 'finish_reason': 'finished',
 'finish_time': datetime.datetime(2018, 3, 18, 4, 47, 30, 595060),
 'log_count/DEBUG': 3,
 'log_count/ERROR': 1,
 'log_count/INFO': 7,
 'memusage/max': 53207040,
 'memusage/startup': 53207040,
 'response_received_count': 2,
 'scheduler/dequeued': 1,
 'scheduler/dequeued/memory': 1,
 'scheduler/enqueued': 1,
 'scheduler/enqueued/memory': 1,
 'spider_exceptions/NotImplementedError': 1,
 'start_time': datetime.datetime(2018, 3, 18, 4, 47, 29, 597697)}
2018-03-18 04:47:30 [scrapy.core.engine] INFO: Spider closed (finished)

我是python的新手，所以如果有人帮我解决这个问题，那就太好了。

scrapy

scrapy-spider

python

python-3.x

xpath

回答 1

Stack Overflow用户

回答已采纳

发布于 2018-03-17 21:21:15

查看日志中的下列行：

2018-03-18 04:47:30 [scrapy.core.scraper] ERROR: Spider error processing <GET http://www.greatplantpicks.org/plantlists/by_plant_type/conifer> (referer: None)
Traceback (most recent call last):
  File "/home/mushfika/.local/lib/python3.5/site-packages/twisted/internet/defer.py", line 653, in _runCallbacks
    current.result = callback(current.result, *args, **kw)
  File "/home/mushfika/.local/lib/python3.5/site-packages/scrapy/spiders/__init__.py", line 90, in parse
    raise NotImplementedError('{}.parse callback is not defined'.format(self.__class__.__name__))
NotImplementedError: PlantsSpider.parse callback is not defined