我正在学习Scrapy和网站爬虫的基础知识,非常感谢您的帮助。我是按照教程建立了一个简单的Scrapy爬虫程序。
它可以正常工作,但是它无法像预期一样爬取所有页面。
我的爬虫代码如下:
from scrapy.spider import BaseSpider
from scrapy.selector import HtmlXPathSelector
from scrapy.http.request import Request
from fraist.items import FraistItem
import re
class fraistspider(BaseSpider):
name = "fraistspider"
allowed_domain = ["99designs.com"]
start_urls = ["http://99designs.com/designer-blog/"]
def parse(self, response):
hxs = HtmlXPathSelector(response)
links = hxs.select("//div[@class='pagination']/a/@href").extract()
#We stored already crawled links in this list
crawledLinks = []
#Pattern to check proper link
linkPattern = re.compile("^(?:ftp|http|https):\/\/(?:[\w\.\-\+]+:{0,1}[\w\.\-\+]*@)?(?:[a-z0-9\-\.]+)(?::[0-9]+)?(?:\/|\/(?:[\w#!:\.\?\+=&%@!\-\/\(\)]+)|\?(?:[\w#!:\.\?\+=&%@!\-\/\(\)]+))?$")
for link in links:
# If it is a proper link and is not checked yet, yield it to the Spider
if linkPattern.match(link) and not link in crawledLinks:
crawledLinks.append(link)
yield Request(link, self.parse)
posts = hxs.select("//article[@class='content-summary']")
items = []
for post in posts:
item = FraistItem()
item["title"] = post.select("div[@class='summary']/h3[@class='entry-title']/a/text()").extract()
item["link"] = post.select("div[@class='summary']/h3[@class='entry-title']/a/@href").extract()
item["content"] = post.select("div[@class='summary']/p/text()").extract()
items.append(item)
for item in items:
yield item
输出结果为:
'title': [u'Design a poster in the style of Saul Bass']}
2015-05-20 16:22:41+0100 [fraistspider] DEBUG: Scraped from <200 http://nnbdesig
ner.wpengine.com/designer-blog/>
{'content': [u'Helping a company come up with a branding strategy can be
exciting\xa0and intimidating, all at once. It gives a designer the opportunity
to make a great visual impact with a brand, but requires skills in logo, print a
nd digital design. If you\u2019ve been hesitating to join a 99designs Brand Iden
tity Pack contest, here are a... '],
'link': [u'http://99designs.com/designer-blog/2015/05/07/tips-brand-ide
ntity-pack-design-success/'],
'title': [u'99designs\u2019 tips for a successful Brand Identity Pack d
esign']}
2015-05-20 16:22:41+0100 [fraistspider] DEBUG: Redirecting (301) to <GET http://
nnbdesigner.wpengine.com/> from <GET http://99designs.com/designer-blog/page/10/
>
2015-05-20 16:22:41+0100 [fraistspider] DEBUG: Redirecting (301) to <GET http://
nnbdesigner.wpengine.com/> from <GET http://99designs.com/designer-blog/page/11/
>
2015-05-20 16:22:41+0100 [fraistspider] INFO: Closing spider (finished)
2015-05-20 16:22:41+0100 [fraistspider] INFO: Stored csv feed (100 items) in: da
ta.csv
2015-05-20 16:22:41+0100 [fraistspider] INFO: Dumping Scrapy stats:
{'downloader/request_bytes': 4425,
'downloader/request_count': 16,
'downloader/request_method_count/GET': 16,
'downloader/response_bytes': 126915,
'downloader/response_count': 16,
'downloader/response_status_count/200': 11,
'downloader/response_status_count/301': 5,
'dupefilter/filtered': 41,
'finish_reason': 'finished',
'finish_time': datetime.datetime(2015, 5, 20, 15, 22, 41, 738000),
'item_scraped_count': 100,
'log_count/DEBUG': 119,
'log_count/INFO': 8,
'request_depth_max': 5,
'response_received_count': 11,
'scheduler/dequeued': 16,
'scheduler/dequeued/memory': 16,
'scheduler/enqueued': 16,
'scheduler/enqueued/memory': 16,
'start_time': datetime.datetime(2015, 5, 20, 15, 22, 40, 718000)}
2015-05-20 16:22:41+0100 [fraistspider] INFO: Spider closed (finished)
您可以看到,'item_scraped_count'
为100,尽管总共有122页,每页10篇文章,应该更多。
从输出中,我可以看到存在301重定向问题,但我不明白为什么会导致问题。我尝试了另一种方法重写我的爬虫代码,但是在几个条目后,它再次出现问题,大约在同一部分。
非常感谢任何帮助。谢谢!