Scrapy 跟随分页 AJAX 请求 - POST

Posted

技术标签:

【中文标题】Scrapy 跟随分页 AJAX 请求 - POST【英文标题】：Scrapy follow pagination AJAX Request - POST 【发布时间】：2015-07-23 06:25:04 【问题描述】：

我对scrapy很陌生，并且已经构建了一些蜘蛛。 我正在尝试从这个page 中抓取评论。到目前为止，我的蜘蛛会抓取第一页并抓取这些项目，但在分页时它不会跟随链接。

我知道发生这种情况是因为它是一个 Ajax 请求，但它是一个 POST 而不是一个 GET，我是关于这些的新手，但我读过 this。我已阅读此帖子here 并按照“迷你教程”从似乎是的响应中获取 url 

http://www.pcguia.pt/category/reviews/sorter=recent&location=&loop=main+loop&action=sort&view=grid&columns=3&paginated=2&currentquery%5Bcategory_name%5D=reviews

但是当我尝试在浏览器上打开它时，它说

"Página nao encontrada"="未找到页面"

到目前为止，我的想法是否正确，我错过了什么？

编辑：我的蜘蛛：

import scrapy
import json
from scrapy.http import FormRequest
from scrapy.contrib.linkextractors.sgml import SgmlLinkExtractor
from scrapy.selector import Selector
from pcguia.items import ReviewItem

class PcguiaSpider(scrapy.Spider):
    name = "pcguia" #spider name to call in terminal
    allowed_domains = ['pcguia.pt'] #the domain where the spider is allowed to crawl
    start_urls = ['http://www.pcguia.pt/category/reviews/#paginated=1'] #url from which the spider will start crawling
    page_incr = 1
    pagination_url = 'http://www.pcguia.pt/wp-content/themes/flavor/functions/ajax.php'

    def parse(self, response):

        sel = Selector(response)

        if self.page_incr > 1:
            json_data = json.loads(response.body)
            sel = Selector(text=json_data.get('content', ''))


        hxs = Selector(response)

        item_pub = ReviewItem()

        item_pub['date']= hxs.xpath('//span[@class="date"]/text()').extract() # is in the format year-month-dayThours:minutes:seconds-timezone ex: 2015-03-31T09:40:00-0700


        item_pub['title'] = hxs.xpath('//title/text()').extract()

        #pagination code starts here 
        # if page has content
        if sel.xpath('//div[@class="panel-wrapper"]'):
            self.page_incr +=1
            formdata = 
                        'sorter':'recent',
                        'location':'main loop',
                        'loop':'main loop',
                        'action':'sort',
                        'view':'grid',
                        'columns':'3',
                        'paginated':str(self.page_incr),
                        'currentquery[category_name]':'reviews'
                        
            yield FormRequest(url=self.pagination_url, formdata=formdata, callback=self.parse)
        else:
            return

        yield item_pub

输出：

2015-05-12 14:53:45+0100 [scrapy] INFO: Scrapy 0.24.5 started (bot: pcguia)
2015-05-12 14:53:45+0100 [scrapy] INFO: Optional features available: ssl, http11
2015-05-12 14:53:45+0100 [scrapy] INFO: Overridden settings: 'NEWSPIDER_MODULE': 'pcguia.spiders', 'SPIDER_MODULES': ['pcguia.spiders'], 'BOT_NAME': 'pcguia'
2015-05-12 14:53:45+0100 [scrapy] INFO: Enabled extensions: LogStats, TelnetConsole, CloseSpider, WebService, CoreStats, SpiderState
2015-05-12 14:53:45+0100 [scrapy] INFO: Enabled downloader middlewares: HttpAuthMiddleware, DownloadTimeoutMiddleware, UserAgentMiddleware, RetryMiddleware, DefaultHeadersMiddleware, MetaRefreshMiddleware, HttpCompressionMiddleware, RedirectMiddleware, CookiesMiddleware, ChunkedTransferMiddleware, DownloaderStats
2015-05-12 14:53:45+0100 [scrapy] INFO: Enabled spider middlewares: HttpErrorMiddleware, OffsiteMiddleware, RefererMiddleware, UrlLengthMiddleware, DepthMiddleware
2015-05-12 14:53:45+0100 [scrapy] INFO: Enabled item pipelines: 
2015-05-12 14:53:45+0100 [pcguia] INFO: Spider opened
2015-05-12 14:53:45+0100 [pcguia] INFO: Crawled 0 pages (at 0 pages/min), scraped 0 items (at 0 items/min)
2015-05-12 14:53:45+0100 [scrapy] DEBUG: Telnet console listening on 127.0.0.1:6033
2015-05-12 14:53:45+0100 [scrapy] DEBUG: Web service listening on 127.0.0.1:6090
2015-05-12 14:53:45+0100 [pcguia] DEBUG: Crawled (200) <GET http://www.pcguia.pt/category/reviews/#paginated=1> (referer: None)
2015-05-12 14:53:45+0100 [pcguia] DEBUG: Scraped from <200 http://www.pcguia.pt/category/reviews/>
    'date': '',
     'title': [u'Reviews | PCGuia'],

2015-05-12 14:53:47+0100 [pcguia] DEBUG: Crawled (200) <POST http://www.pcguia.pt/wp-content/themes/flavor/functions/ajax.php> (referer: http://www.pcguia.pt/category/reviews/)
2015-05-12 14:53:47+0100 [pcguia] DEBUG: Scraped from <200 http://www.pcguia.pt/wp-content/themes/flavor/functions/ajax.php>
    'date': ''
     'title': ''

【问题讨论】：

你从哪里获取日期？？我在那个日期找不到任何令人满意的 xpath 吗？标题是指评论标题对吗？好像你已经采取了页面标题。发布您想要获取的可能输出 我从这里获取日期：pcguia.pt/desktops/asus-rog-gr8 xpath '//span[@class="date"]/text()' 指向 ' Publicado a 10 Dezembro, 2014 ' 我已经更新了代码检查答案 【参考方案1】：

你可以试试这个

from scrapy.http import FormRequest
from scrapy.selector import Selector
# other imports

class SpiderClass(Spider)
    # spider name and all
    page_incr = 1
    pagination_url = 'http://www.pcguia.pt/wp-content/themes/flavor/functions/ajax.php'

    def parse(self, response):

        sel = Selector(response)

        if page_incr > 1:
            json_data = json.loads(response.body)
            sel = Selector(text=json_data.get('content', ''))

        # your code here 

        #pagination code starts here 
        # if page has content
        if sel.xpath('//div[@class="panel-wrapper"]'):
            self.page_incr +=1
            formdata = 
                    'sorter':'recent',
                    'location':'main loop',
                    'loop':'main loop',
                    'action':'sort',
                    'view':'grid',
                    'columns':'3',
                    'paginated':str(self.page_incr),
                    'currentquery[category_name]':'reviews'
                    
            yield FormRequest(url=self.pagination_url, formdata=formdata, callback=self.parse)
        else:
            return

我已经使用scrapy shell 测试过它的工作原理，

在scrapy Shell中

In [0]: response.url
Out[0]: 'http://www.pcguia.pt/category/reviews/#paginated=1'

    In [1]: from scrapy.http import FormRequest

In [2]: from scrapy.selector import Selector

In [3]: import json

In [4]: response.xpath('//h2/a/text()').extract()
Out[4]: 
        [u'HP Slate 8 Plus',
         u'Astro A40 +MixAmp Pro',
         u'Asus ROG G751J',
         u'BQ Aquaris E5 HD 4G',
         u'Asus GeForce GTX980 Strix',
         u'AlienTech BattleBox Edition',
         u'Toshiba Encore Mini WT7-C',
         u'Samsung Galaxy Note 4',
         u'Asus N551JK',
         u'Western Digital My Passport Wireless',
         u'Nokia Lumia 735',
         u'Photoshop Elements 13',
         u'AMD Radeon R9 285',
         u'Asus GeForce GTX970 Stryx',
         u'TP-Link AC750 Wifi Repeater']

In [5]: url = "http://www.pcguia.pt/wp-content/themes/flavor/functions/ajax.php"

In [6]: formdata = 
        'sorter':'recent',
        'location':'main loop',
        'loop':'main loop',
        'action':'sort',
        'view':'grid',
        'columns':'3',
        'paginated':'2',
        'currentquery[category_name]':'reviews'
        

In [7]: r = FormRequest(url=url, formdata=formdata)

In [8]: fetch(r)
        2015-05-12 18:29:16+0530 [default] DEBUG: Crawled (200) <POST http://www.pcguia.pt/wp-content/themes/flavor/functions/ajax.php> (referer: None)
        [s] Available Scrapy objects:
        [s]   crawler    <scrapy.crawler.Crawler object at 0x7fcc247c4590>
        [s]   item       
        [s]   r          <POST http://www.pcguia.pt/wp-content/themes/flavor/functions/ajax.php>
        [s]   request    <POST http://www.pcguia.pt/wp-content/themes/flavor/functions/ajax.php>
        [s]   response   <200 http://www.pcguia.pt/wp-content/themes/flavor/functions/ajax.php>
        [s]   settings   <scrapy.settings.Settings object at 0x7fcc2a74f450>
        [s]   spider     <Spider 'default' at 0x7fcc239ba990>
        [s] Useful shortcuts:
        [s]   shelp()           Shell help (print this help)
        [s]   fetch(req_or_url) Fetch request (or URL) and update local objects
        [s]   view(response)    View response in a browser

In [9]: json_data = json.loads(response.body)

In [10]: sell = Selector(text=json_data.get('content', ''))

In [11]: sell.xpath('//h2/a/text()').extract()
Out[11]: 
        [u'Asus ROG GR8',
         u'Devolo dLAN 1200+',
         u'Yezz Billy 4,7',
         u'Sony Alpha QX1',
         u'Toshiba Encore2 WT10',
         u'BQ Aquaris E5 FullHD',
         u'Toshiba Canvio AeroMobile',
         u'Samsung Galaxy Tab S 10.5',
         u'Modecom FreeTab 7001 HD',
         u'Steganos Online Shield ***',
         u'AOC G2460PG G-Sync',
         u'AMD Radeon R7 SSD',
         u'Nvidia Shield',
         u'Asus ROG PG278Q GSync',
         u'NOX Krom Kombat']

编辑

import scrapy
import json
from scrapy.http import FormRequest, Request
from scrapy.contrib.linkextractors.sgml import SgmlLinkExtractor
from scrapy.selector import Selector
from pcguia.items import ReviewItem
from dateutil import parser
import re


class PcguiaSpider(scrapy.Spider):
    name = "pcguia" #spider name to call in terminal
    allowed_domains = ['pcguia.pt'] #the domain where the spider is allowed to crawl
    start_urls = ['http://www.pcguia.pt/category/reviews/#paginated=1'] #url from which the spider will start crawling
    page_incr = 1
    pagination_url = 'http://www.pcguia.pt/wp-content/themes/flavor/functions/ajax.php'

    def parse(self, response):
        sel = Selector(response)
        if self.page_incr > 1:
            json_data = json.loads(response.body)
            sel = Selector(text=json_data.get('content', ''))
        review_links = sel.xpath('//h2/a/@href').extract()
        for link in review_links:
            yield Request(url=link, callback=self.parse_review)
        #pagination code starts here 
        # if page has content
        if sel.xpath('//div[@class="panel-wrapper"]'):
            self.page_incr +=1
            formdata = 
                        'sorter':'recent',
                        'location':'main loop',
                        'loop':'main loop',
                        'action':'sort',
                        'view':'grid',
                        'columns':'3',
                        'paginated':str(self.page_incr),
                        'currentquery[category_name]':'reviews'
                        
            yield FormRequest(url=self.pagination_url, formdata=formdata, callback=self.parse)
        else:
            return

    def parse_review(self, response):
        month_matcher = 'novembro|janeiro|agosto|mar\xe7o|fevereiro|junho|dezembro|julho|abril|maio|outubro|setembro'
        month_dict = u'abril': u'April',
                                u'agosto': u'August',
                                u'dezembro': u'December',
                                u'fevereiro': u'February',
                                u'janeiro': u'January',
                                u'julho': u'July',
                                u'junho': u'June',
                                u'maio': u'May',
                                u'mar\xe7o': u'March',
                                u'novembro': u'November',
                                u'outubro': u'October',
                                u'setembro': u'September'
        review_date = response.xpath('//span[@class="date"]/text()').extract()
        review_date = review_date[0].strip().strip('Publicado a').lower() if review_date else ''
        month = re.findall('%s'% month_matcher, review_date)[0]
        _date = parser.parse(review_date.replace(month, month_dict.get(month))).strftime('%Y-%m-%dT%H:%M:%T')
        title = response.xpath('//h1[@itemprop="itemReviewed"]/text()').extract()
        title = title[0].strip() if title else ''
        item_pub = ReviewItem(
            date=_date,
            title=title)
        yield item_pub

输出

'date': '2014-11-05T00:00:00', 'title': u'Samsung Galaxy Tab S 10.5'

【讨论】：

好吧，我也试过了，但是没有加载新项目，当我输入 pcguia.pt/category/reviews/#paginated=2 时，它会显示与 paginated=1 相同的评论：S 你说得对，我还没有测试过，我现在将更改分析器 我已经根据您的建议修改了我的蜘蛛代码，但仍然无法正常工作：S 是的，它正在工作，非常感谢，这是一个很大的帮助:)【参考方案2】：

正确的解决方案是使用 selenium。 看看你面临的问题是你的scrapy spider没有更新新的源代码。

Selenium 将帮助您点击后续链接并将更新的源代码传递给您的 response.xpath。

如果你只分享你正在使用的scrapy代码，我可以为你提供更多帮助。

【讨论】：

没问题...真的需要硒吗？不能像以前的答案那样formRequest吗？

以上是关于Scrapy 跟随分页 AJAX 请求 - POST的主要内容，如果未能解决你的问题，请参考以下文章

如何使用 Scrapy FormRequest 在分页的 .asp 站点上模拟下一页链接请求

Django ajax异步请求分页的实现

Scrapy 解析 JSON 输出

Ajax 请求不适用于数据表分页

让 Scrapy 跟随链接并收集数据

Ajax提交分页请求，实现异步刷新效果