我有一个形式的网址:
example.com/foo/bar/page_1.html
总共有53页,每页约20行。
我基本上想从所有页面中获取所有行,即〜53 * 20个项目。
我的parse方法中有有效的代码,该代码分析单个页面,每个项目也深入一页,以获取有关该项目的更多信息:
def parse(self, response): hxs = HtmlXPathSelector(response) restaurants = hxs.select('//*[@id="contenido-resbus"]/table/tr[position()>1]') for rest in restaurants: item = DegustaItem() item['name'] = rest.select('td[2]/a/b/text()').extract()[0] # some items don't have category associated with them try: item['category'] = rest.select('td[3]/a/text()').extract()[0] except: item['category'] = '' item['urbanization'] = rest.select('td[4]/a/text()').extract()[0] # get profile url rel_url = rest.select('td[2]/a/@href').extract()[0] # join with base url since profile url is relative base_url = get_base_url(response) follow = urljoin_rfc(base_url,rel_url) request = Request(follow, callback = parse_profile) request.meta['item'] = item return request def parse_profile(self, response): item = response.meta['item'] # item['address'] = figure out xpath return item
问题是,如何爬行每个页面?
example.com/foo/bar/page_1.html example.com/foo/bar/page_2.html example.com/foo/bar/page_3.html ... ... ... example.com/foo/bar/page_53.html
您有两种选择可以解决您的问题。一般的做法是使用yield来生成新请求return。这样,您可以从单个回调中发出多个新请求。在http://doc.scrapy.org/en/latest/topics/spiders.html#basespider- example中查看第二个示例。
yield
return
在您的情况下,可能有一个更简单的解决方案:只需从这样的模式中生成启动urs列表:
class MySpider(BaseSpider): start_urls = ['http://example.com/foo/bar/page_%s.html' % page for page in xrange(1,54)]