如何无限滚动抓取网站？

我想爬行这个网站。我写了一个蜘蛛，但它只爬首页，即前 52 项。

我试过这段代码：

from scrapy.spider import BaseSpider
from scrapy.selector import HtmlXPathSelector
from scrapy.http import Request
a=[]
from aqaq.items import aqaqItem
import os
import urlparse
import ast

    class aqaqspider(BaseSpider):
        name = "jabong"
        allowed_domains = ["jabong.com"]
        start_urls = [
            "http://www.jabong.com/women/clothing/womens-tops/",
        ]

        def parse(self, response):
            # ... Extract items in the page using extractors
                    n=3
                    ct=1

                    hxs = HtmlXPathSelector(response)
                    sites=hxs.select('//div[@id="page"]')
                    for site in sites:
                            name=site.select('//div[@id="content"]/div[@class="l-pageWrapper"]/div[@class="l-main"]/div[@class="box box-bgcolor"]/section[@class="box-bd pan mtm"]/ul[@id="productsCatalog"]/li/a/@href').extract()
                            print name
                            print ct
                            ct=ct+1
                            a.append(name)
                    req= Request (url="http://www.jabong.com/women/clothing/womens-tops/?page=" + str(n) ,
                    headers = {"Referer": "http://www.jabong.com/women/clothing/womens-tops/",
                            "X-Requested-With": "XMLHttpRequest"},callback=self.parse,dont_filter=True)

                    return req # and your items

它显示以下输出：

2013-10-31 09:22:42-0500 [jabong] DEBUG: Crawled (200) <GET http://www.jabong.com/women/clothing/womens-tops/?page=3> (referer: http://www.jabong.com/women/clothing/womens-tops/)
2013-10-31 09:22:42-0500 [jabong] DEBUG: Filtered duplicate request: <GET http://www.jabong.com/women/clothing/womens-tops/?page=3> - no more duplicates will be shown (see DUPEFILTER_CLASS)
2013-10-31 09:22:42-0500 [jabong] INFO: Closing spider (finished)
2013-10-31 09:22:42-0500 [jabong] INFO: Dumping Scrapy stats:

当我把dont_filter=True它永远不会停止。

Yes, dont_filter必须在这里使用，因为只有pageXHR 请求中的 GET 参数更改为http://www.jabong.com/women/clothing/womens-tops/?page=X每次将页面向下滚动到底部时。

现在你需要弄清楚如何停止爬行。这其实很简单——只需检查队列中下一页上没有产品的时间并提高CloseSpider例外.

这是一个适合我的完整代码示例（停在第 234 页）：

import scrapy
from scrapy.exceptions import CloseSpider
from scrapy.spider import BaseSpider
from scrapy.http import Request


class Product(scrapy.Item):
    brand = scrapy.Field()
    title = scrapy.Field()


class aqaqspider(BaseSpider):
    name = "jabong"
    allowed_domains = ["jabong.com"]
    start_urls = [
        "http://www.jabong.com/women/clothing/womens-tops/?page=1",
    ]
    page = 1

    def parse(self, response):
        products = response.xpath("//li[@data-url]")

        if not products:
            raise CloseSpider("No more products!")

        for product in products:
            item = Product()
            item['brand'] = product.xpath(".//span[contains(@class, 'qa-brandName')]/text()").extract()[0].strip()
            item['title'] = product.xpath(".//span[contains(@class, 'qa-brandTitle')]/text()").extract()[0].strip()
            yield item

        self.page += 1
        yield Request(url="http://www.jabong.com/women/clothing/womens-tops/?page=%d" % self.page,
                      headers={"Referer": "http://www.jabong.com/women/clothing/womens-tops/", "X-Requested-With": "XMLHttpRequest"},
                      callback=self.parse, 
                      dont_filter=True)