抓取图像失败

Question

我正在尝试使用以下残片代码从网站抓取图像：

import urlparse
from PIL import Image
from scrapy.exceptions import DropItem, NotConfigured, IgnoreRequest
from scrapy.spider import BaseSpider
from scrapy.contrib.spiders import CrawlSpider, Rule
from scrapy.contrib.linkextractors.sgml import SgmlLinkExtractor
from scrapy.contrib.loader import XPathItemLoader
from scrapy.selector import HtmlXPathSelector
from scrapy.http.request import Request

from scrapy.contrib.pipeline.images import ImagesPipeline
from mobile.items import Website

class MobileSpider(CrawlSpider):
    name = "mobile"
    allowed_domains = ["mobile-store.ro"]
    start_urls = ["http://www.mobile-store.ro/produse/"]
    rules = (
        Rule(SgmlLinkExtractor(allow=r"/produs/d+"), follow=True),
        Rule(SgmlLinkExtractor(allow=r"/produse/d+"), callback='parse_item')
    )

    def parse(self, response, response2):
        hxs = HtmlXPathSelector(response)
        next_page = hxs.select("//ul[@class='products']/li/a/@href").extract()
        if not not next_page:
            yield Request(next_page[0], self.parse)
        sites = hxs.select('//div[@id="wrapper"]/div[@id="content"]')
        items = []

        for site in sites:
            item = Website()
            item['nume'] = site.select('//div[@class="summary"]/h1[@class="product_title entry-title"]/text()').extract()
            item['categorie'] = site.select('//div[@class="summary"]/div[@class="product_meta"]/span[@class="posted_in"]/a/text()').extract()
            item['brand'] = site.select('//div[@class="summary"]/div[@class="product_meta"]/span[@class="tagged_as"]/a/text()').extract()
            item['descriere'] = site.select('//div[@class="woocommerce_tabs"]/div[@id="tab-description"]/p/text()').extract()
            image_relative_url = site.select('//div[@class="ad-image-wrapper"]/div[@class="ad-image"]/img[@class="lightbox"]/@src').extract()
            item['image_urls'] = [urlparse.urljoin(response.url,image_relative_url)]
            #item['image_urls'] = site.select('//div[@class="ad-image-wrapper"]/div[@class="ad-image"]/img[@class="lightbox"]/@src').extract()
            item['pret'] = site.select('//div[@class="summary"]/div[1]/p[@class="price"]/span[@class="amount"]/text()').extract()
            item['url'] = response.url
            items.append(item)
        for item in items:
            yield item

settings.py:
SPIDER_MODULES = ['mobile.spiders']
NEWSPIDER_MODULE = 'mobile.spiders'
DEFAULT_ITEM_CLASS = 'mobile.items.Website'

ITEM_PIPELINES = ['scrapy.contrib.pipeline.images.ImagesPipeline']

items.py:
from scrapy.item import Item, Field

class Website(Item):
    nume = Field()
    descriere = Field()
    categorie = Field()
    brand = Field()
    pret = Field()
    url = Field()
    image_urls = Field()
    images = Field()
    image_paths = Field()

pipelines.py:
from mobile.contrib.pipeline.images import ImagesPipeline
from scrapy.exceptions import DropItem
from scrapy.http import Request

class MyImagesPipeline(ImagesPipeline):

    def get_media_requests(self, item, info):
        for image_url in item['image_urls']:
            yield Request(image_url)

    def item_completed(self, results, item, info):
        image_paths = [x['path'] for ok, x in results if ok]
        if not image_paths:
            raise DropItem("Item contains no images")
        item['image_paths'] = image_paths
        return item

当我尝试使用以下代码获取图像url时，会出现问题：

for site in sites:
        item = Website()
        item['nume'] = site.select('//div[@class="summary"]/h1[@class="product_title entry-title"]/text()').extract()
        item['categorie'] = site.select('//div[@class="summary"]/div[@class="product_meta"]/span[@class="posted_in"]/a/text()').extract()
        item['brand'] = site.select('//div[@class="summary"]/div[@class="product_meta"]/span[@class="tagged_as"]/a/text()').extract()
        item['descriere'] = site.select('//div[@class="woocommerce_tabs"]/div[@id="tab-description"]/p/text()').extract()
        image_relative_url = site.select('//div[@class="ad-image-wrapper"]/div[@class="ad-image"]/img[@class="lightbox"]/@src').extract()
        item['image_urls'] = [urlparse.urljoin(response.url2,image_relative_url)]
        #item['image_urls'] = site.select('//div[@class="ad-image-wrapper"]/div[@class="ad-image"]/img[@class="lightbox"]/@src').extract()
        item['pret'] = site.select('//div[@class="summary"]/div[1]/p[@class="price"]/span[@class="amount"]/text()').extract()
        item['url'] = response.url
        items.append(item)
    for item in items:
        yield item

它将返回页面url而不是图像url。所有其他字段都已正确爬网。关于如何解决此问题并正确获取图像url的任何线索？

Answer 1

这是因为图像（以及ad-image-wrapperdiv的全部内容）是通过javascript动态填充的。

倾销响应。parse方法中的body帮助我确定实际的图像链接最初保存在ad thumb列表中。因此，请尝试使用以下方法获取图像url：

image_relative_url = site.select('//ul[@class="ad-thumb-list"]/li[@class="first_item"]/a/@href').extract()
if image_relative_url:
    image_relative_url = image_relative_url[0]

希望这就是你所需要的。