First you have to set up a new Scrapy project. Enter a directory where you’d like to store your code and run:
scrapy startproject projectName
To scrape we need a spider. Spiders define how a certain site will be scraped. Here’s the code for a spider that follows the links to the top voted questions on StackOverflow and scrapes some data from each page (source):
import scrapy
class StackOverflowSpider(scrapy.Spider):
name = 'stackoverflow' # each spider has a unique name
start_urls = ['http://stackoverflow.com/questions?sort=votes'] # the parsing starts from a specific set of urls
def parse(self, response): # for each request this generator yields, its response is sent to parse_question
for href in response.css('.question-summary h3 a::attr(href)'): # do some scraping stuff using css selectors to find question urls
full_url = response.urljoin(href.extract())
yield scrapy.Request(full_url, callback=self.parse_question)
def parse_question(self, response):
yield {
'title': response.css('h1 a::text').extract_first(),
'votes': response.css('.question .vote-count-post::text').extract_first(),
'body': response.css('.question .post-text').extract_first(),
'tags': response.css('.question .post-tag::text').extract(),
'link': response.url,
}
Save your spider classes in the projectName\spiders
directory. In this case - projectName\spiders\stackoverflow_spider.py
.
Now you can use your spider. For example, try running (in the project's directory):
scrapy crawl stackoverflow