if response.xpath('//link[contains(@rel,"apple-touch-icon-precomposed")]/@href'):
                apple_touch_url = response.xpath('//link[contains(@rel,"apple-touch-icon-precomposed")]/@href').extract()
                apple_touch_url=[link for link in apple_touch_url if 'https' in link or 'http' in link ]
                item['logo'] = apple_touch_url
                if not apple_touch_url:



        elif response.xpath('//link[contains(@rel,"icon")]/@href'):
                rel_url=response.xpath('//link[contains(@rel,"icon")]/@href').extract()
                item['logo']=rel_url
                print(rel_url)
        elif response.xpath('//link[contains(@rel,"shortcut icon")]/@href'):

            print('打印shortcut链接')
            shortcut_url=response.xpath('//link[contains(@rel,"shortcut icon")]/@href').extract()
            item['logo']=shortcut_url
            print(shortcut_url)
        else:
           print('打印favicon链接')
           item['logo']=response.url+'/favicon.ico'