code

from scrapy.linkextractors import LinkExtractor
from scrapy.selector import Selector




class WikispiderSpider(CrawlSpider):
    name = "wikispider"
    allowed_domains = ["wikipedia.org"]
    start_urls = (
        'https://en.wikipedia.org/wiki/Mathematics',
    )
    rules = (

        
         Rule(LinkExtractor(restrict_xpaths=('//div[@class="mw-body-content"]//a/@href'))),
         Rule(LinkExtractor(allow=("https://en.wikipedia.org/wiki/",)),callback='parse_item'),

    )

    def parse(self, response):

       hxs = Selector(response)
       print hxs.xpath('//h1[@class= "firstHeading"]/span/text()').extract()
       #heading = hxs.select('//h1[@class="firstHeading"]/span/text()').extract()
       pass