未收到数据时的递归

Question

如何运行下载和解析相同的URL，而未收到所需的数据，或者递归的调用是＆gt; 5次？

例如，我需要从example.com获取h1，但服务器返回不同的页面：使用h1，没有它。我希望代码运行下载和解析网址，而h1没有得到或递归调用＆gt; 5次。

例如

import re
from kupito.items import KupitoItem
from scrapy.linkextractors import LinkExtractor
from scrapy.spiders import CrawlSpider, Rule
from scrapy.selector import Selector

class idpkzSpider(CrawlSpider):

name = 'idp.kz'
allowed_domains = ['idp.kz']
start_urls = [
    'http://idp.kz/index.php/katalog-tovarov/monitors'
]

rules = (
    Rule(LinkExtractor(allow=('.*start=\d+$')), callback='parse_start_url', follow=True),
)

def parse_start_url(self, response):

    items = []

    hxs = Selector(response)
    dirEl = hxs.xpath('//h1/text()').extract()
    goods = hxs.xpath('//div[@class=\'jshop list_product\']/div[@class=\'block_product\']')

    if dirEl and len(goods) > 0:
        dirName = dirEl[0].encode('utf-8').strip()
        for good in goods:
            name = good.xpath('div//div[@class=\'name\']/a/text()').extract()
            price = good.xpath('div//div[@class=\'jshop_price\']/span/text()').extract()
            url = good.xpath('div//div[@class=\'name\']/a/@href').extract()
            if name and price and url:
                item = KupitoItem()
                item['name'] = name[0].encode('utf-8').strip()
                item['price'] = price[0].encode('utf-8').strip()
                item['url'] = url[0].encode('utf-8').strip()
                item['dirName'] = dirName
                items.append(item)
    return items