Question

我不知道问题出在哪里可能非常容易修复，因为我不熟悉scrapy。谢谢你的帮助！

我的蜘蛛：

from scrapy.spiders import CrawlSpider, Rule
from scrapy.selector import HtmlXPathSelector
from scrapy.linkextractors import LinkExtractor
from scrapy.item import Item

class ArticleSpider(CrawlSpider):
    name = "article"
    allowed_domains = ["economist.com"]
    start_urls = ['http://www.economist.com/sections/science-technology']

    rules = [
      Rule(LinkExtractor(restrict_xpaths='//article'), callback='parse_item', follow=True),
    ]

    def parse_item(self, response):
        for sel in response.xpath('//div/article'):
            item = scrapy.Item()
            item ['title'] = sel.xpath('a/text()').extract()
            item ['link'] = sel.xpath('a/@href').extract()
            item ['desc'] = sel.xpath('text()').extract()
            return item

产品：

import scrapy

class EconomistItem(scrapy.Item):
    title = scrapy.Field()
    link = scrapy.Field()
    desc = scrapy.Field()

日志的一部分：

INFO: Crawled 0 pages (at 0 pages/min), scraped 0 items (at 0 items/min)
Crawled (200) <GET http://www.economist.com/sections/science-technology> (referer: None)

编辑：

我添加了alecxe提出的更改后发生了另一个问题：

日志：

[scrapy] DEBUG: Crawled (200) <GET http://www.economist.com/news/science-and-technology/21688848-stem-cells-are-starting-prove-their-value-medical-treatments-curing-multiple> (referer: http://www.economist.com/sections/science-technology)
2016-02-04 14:05:01 [scrapy] DEBUG: Crawled (200) <GET http://www.economist.com/news/science-and-technology/21689501-beating-go-champion-machine-learning-computer-says-go> (referer: http://www.economist.com/sections/science-technology)
2016-02-04 14:05:02 [scrapy] ERROR: Spider error processing <GET http://www.economist.com/news/science-and-technology/21688848-stem-cells-are-starting-prove-their-value-medical-treatments-curing-multiple> (referer: http://www.economist.com/sections/science-technology)
Traceback (most recent call last):
  File "/usr/local/lib/python2.7/site-packages/scrapy/utils/defer.py", line 102, in iter_errback
    yield next(it)
  File "/usr/local/lib/python2.7/site-packages/scrapy/spidermiddlewares/offsite.py", line 28, in process_spider_output
    for x in result:
  File "/usr/local/lib/python2.7/site-packages/scrapy/spidermiddlewares/referer.py", line 22, in <genexpr>
    return (_set_referer(r) for r in result or ())
  File "/usr/local/lib/python2.7/site-packages/scrapy/spidermiddlewares/urllength.py", line 37, in <genexpr>
    return (r for r in result or () if _filter(r))
  File "/usr/local/lib/python2.7/site-packages/scrapy/spidermiddlewares/depth.py", line 54, in <genexpr>
    return (r for r in result or () if _filter(r))
  File "/usr/local/lib/python2.7/site-packages/scrapy/spiders/crawl.py", line 67, in _parse_response
    cb_res = callback(response, **cb_kwargs) or ()
  File "/Users/FvH/Desktop/Python/projects/economist/economist/spiders/article.py", line 18, in parse_item
    item = scrapy.Item()
NameError: global name 'scrapy' is not defined

设定：

BOT_NAME = 'economist'

    SPIDER_MODULES = ['economist.spiders']
    NEWSPIDER_MODULE = 'economist.spiders'
    USER_AGENT = "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_11_2) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/48.0.2564.97 Safari/537.36"

如果我想将数据导出到csv文件中，那么它显然是空的。

由于

Answer 1

parse_item未正确缩进，应为：

class ArticleSpider(CrawlSpider):
    name = "article"
    allowed_domains = ["economist.com"]
    start_urls = ['http://www.economist.com/sections/science-technology']

    rules = [
      Rule(LinkExtractor(allow=r'Items'), callback='parse_item', follow=True),
    ]

    def parse_item(self, response):
        for sel in response.xpath('//div/article'):
            item = scrapy.Item()
            item ['title'] = sel.xpath('a/text()').extract()
            item ['link'] = sel.xpath('a/@href').extract()
            item ['desc'] = sel.xpath('text()').extract()
            return item

除此之外还有两点需要解决：

应修改链接提取部分以匹配文章链接：

Rule(LinkExtractor(restrict_xpaths='//article'), callback='parse_item', follow=True),

您需要指定USER_AGENT setting假装是真正的浏览器。否则，response将不包含文章列表：

USER_AGENT = "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_11_2) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/48.0.2564.97 Safari/537.36"

Answer 2

您只导入了Item（并非所有scrapy模块）：

from scrapy.item import Item

所以不要在这里使用scrapy.Item：

for sel in response.xpath('//div/article'):
        item = scrapy.Item()
        item ['title'] = sel.xpath('a/text()').extract()

你应该只使用Item：

for sel in response.xpath('//div/article'):
        item = Item()
        item ['title'] = sel.xpath('a/text()').extract()

或者导入您自己的项目以便使用它。这应该工作（不要忘记将project_name替换为项目名称）：

from project_name.items import EconomistItem
...
for sel in response.xpath('//div/article'):
        item = EconomistItem()
        item ['title'] = sel.xpath('a/text()').extract()

为什么我的scrapy蜘蛛不刮任何东西？

2 个答案: