如何在 3 页级别的蜘蛛中传递带有元数据的项目？

Question

如何在 3 页级别的蜘蛛程序中使用元传递项目？

我错过了什么？如何为每次迭代创建一个新项目？

代码如下：

import scrapy

class GsmSpider(scrapy.Spider):
    name = 'gsm'
    allowed_domains = ['gsmarena.com']
    start_urls = ['https://gsmarena.com/makers.php3']

    # LEVEL1 | all brands

    def parse(self, response):
        gsms = response.xpath('//div[@class="st-text"]/table')
        for gsm in gsms:
            allbranddevicesurl = gsm.xpath('.//a/@href').get()
            brandname = gsm.xpath('.//a/text()').get()
            
            yield response.follow(allbranddevicesurl, callback=self.parse_allbranddevicesurl,
                                    meta= {'brandname': brandname})

    # LEVEL2 | all devices

    def parse_allbranddevicesurl(self, response):
        
        brandname = response.meta['brandname']
        
        phones = response.xpath('//*[@id="review-body"]//li')
        for phone in phones:
            thumbnailurl = phone.xpath('.//a/img/@src').get()
            detailpageurl = phone.xpath('.//a/@href').get()

            yield response.follow(detailpageurl,
                                    callback=self.parse_detailpage,
                                    meta= {'brandname': brandname})

        next_page = response.xpath('//a[@class="pages-next"]/@href').get()
        if next_page is not None:
            yield response.follow(next_page, callback=self.parse_allbranddevicesurl,
                                    meta= {'brandname': brandname})

    # LEVEL3 | detailpage

    def parse_detailpage(self, response):
     
        brandname = response.meta['brandname']
 
        details = response.xpath('//div[@class="article-info"]')
        for detail in details:
            phonename = detail.xpath('.//h1/text()').get()
                
            yield {'brandname': brandname,
                   'phonename': phonename}

我将不胜感激基于我的示例的说明性解决方案。

Answer 1

您的品牌 xpath 不正确。查看代码中的注释。

import scrapy


# you may want to move this class to "items.py" and import it
class GsmItem(scrapy.Item):
    brandname = scrapy.Field()
    thumbnailurl = scrapy.Field()
    detailpageurl = scrapy.Field()
    phonename = scrapy.Field()
    released = scrapy.Field()


class GsmSpider(scrapy.Spider):
    name = 'gsm'
    allowed_domains = ['gsmarena.com']
    start_urls = ['https://gsmarena.com/makers.php3']

    custom_settings = {
        'CONCURRENT_REQUESTS': 4,
        'DOWNLOAD_DELAY': 0.5
    }

    # LEVEL 1 | all brands

    def parse(self, response):
        # This is the original xpath which is wrong. You're just getting the table without the cell in the table.
        # gsms = response.xpath('//div[@class="st-text"]/table')

        # This is the fixed xpath:
        gsms = response.xpath('//div[@class="st-text"]/table//td')

        for gsm in gsms:
            allbranddevicesurl = gsm.xpath('.//a/@href').get()
            brandname = gsm.xpath('.//a/text()').get()

            yield response.follow(allbranddevicesurl, callback=self.parse_allbranddevicesurl,
                                  meta={'brandname': brandname})

    # LEVEL 2 | all devices

    def parse_allbranddevicesurl(self, response):
        brandname = response.meta['brandname']

        phones = response.xpath('//*[@id="review-body"]//li')
        for phone in phones:
            # we should create a new item for every iteration so we won't overwrite it
            item = GsmItem()

            thumbnailurl = phone.xpath('.//a/img/@src').get()
            detailpageurl = phone.xpath('.//a/@href').get()
            item['thumbnailurl'] = thumbnailurl
            item['detailpageurl'] = detailpageurl
            item['brandname'] = brandname

            yield response.follow(detailpageurl,
                                  callback=self.parse_detailpage,
                                  meta={'item': item})

        next_page = response.xpath('//a[@class="pages-next"]/@href').get()
        if next_page is not None:
            yield response.follow(next_page, callback=self.parse_allbranddevicesurl,
                                  meta={'brandname': brandname})

    # LEVEL 3 | detailpage

    def parse_detailpage(self, response):
        item = response.meta['item']

        details = response.xpath('//div[@class="article-info"]')
        for detail in details:
            phonename = detail.xpath('.//h1/text()').get()
            released = detail.xpath('.//ul/li[1]/span[1]/span/text()').get()
            item['phonename'] = phonename
            item['released'] = released

            yield item

如何在 3 页级别的蜘蛛中传递带有元数据的项目？

How can I pass items with meta in a 3 page level spider?

python

scrapy

web-scraping

python-3.x

如何在 3 页级别的蜘蛛程序中使用元传递项目？