想爬取斗鱼的视频信息,http://www.douyutv.com/directory/game/LOL,需要翻页,利用chrome network得到地址为:http://www.douyutv.com/directory/game/LOL?page=1&isAjax=1,用python写程序就无法返回任何数据,是什么原因呢?

代码:
# -*- coding: utf-8 -*-
import scrapy
from scrapy.selector import Selector
from douyutv.items import VideoItem
import pymongo
from scrapy.selector import Selector
class VideoSpider(scrapy.Spider):
name = "video"
allowed_domains = ["http://www.douyutv.com"]
start_urls = []
def start_requests(self):
client = pymongo.MongoClient('mongodb://127.0.0.1')
db = client['douyutv']
items = db.CategoryItem_20160108102540.find({})
for item in items:
url = str('http://www.douyutv.com' + item['href'])
yield scrapy.http.Request(url=url, callback=self.parse, meta={'firstClass':item['firstClass'], 'secondClass':item['secondClass'], 'oriurl':url, 'page':1})
def parse(self, response):
item = VideoItem()
selector = Selector(response)
print response.meta['oriurl']
videos = selector.xpath('//div[@class="items items01 clearfix"]/ul/li')
allpage = int(selector.xpath('//input[@id="allPage"]/@value').extract()[0])
if response.meta['page'] <= allpage:
for video in videos:
title = video.xpath('a/@title').extract()[0]
href = video.xpath('a/@href').extract()[0]
author = video.xpath('a/div[@class="mes"]/div[2]/p[@class="moreMes"]/span[@class="nnt"]/text()').extract()
view = video.xpath('a/div[@class="mes"]/div[2]/p[@class="moreMes"]/span[@class="view"]/text()').extract()
item['firstClass'] = response.meta['firstClass']
item['secondClass'] = response.meta['secondClass']
item['title'] = title
if author:
item['author'] = author[0]
if view:
item['view'] = view[0]
item['href'] = href
yield item
page = response.meta['page'] + 1
url = response.meta['oriurl'] + '?page=' + str(page)
yield scrapy.http.Request(url=url, callback=self.parse, meta={'firstClass':response.meta['firstClass'], 'secondClass':response.meta['secondClass'], 'page':page, 'oriurl':response.meta['oriurl']})