Проблемы экспорта Scrapy JSON

Question

Я следил за некоторыми онлайн-уроками, чтобы использовать Scrapy для удаления Craigslist для электронных писем. У меня есть этот код, но когда я запускаю команду и экспортирую в файл json, он создает файл, но единственное, что там есть, - это один '['.

Любая помощь будет принята с благодарностью. Ниже мой код:

from scrapy.spider import BaseSpider 
from scrapy.selector import HtmlXPathSelector 
from scrapy_demo.items import ScrapyDemoItem
import urlparse 
from scrapy.http.request import Request

class ScrapyDemoSpider(BaseSpider): 
    name = "scrapy_demo"
    allowed_domains = ["buffalo.craigslist.org"]
    start_urls = ['http://buffalo.craigslist.org/search/cps/']

    def parse(self, response):
        hxs = HtmlXPathSelector(response) 
        listings = hxs.select('//....') 
        links = []

        #scrap listings page to get listing links
        for listing in listings:
            link = listing.select('..../@href').extract()[0]
            links.append(link)

        #parse listing url to get content of the listing page
        for link in links:
            item = ScrapyDemoItem()
            item['link'] = link
            yield Request(urlparse.urljoin(response.url, link), meta={'item': item}, callback=self.parse_listing_page)

            #get next button link
            next_page = hxs.select("//..../@href").extract()[0]
            if next_page:
                yield Request(urlparse.urljoin(response.url, next_page), self.parse)

    #scrap listing page to get content
    def parse_listing_page(self, response):
        hxs = HtmlXPathSelector(response)
        item = response.request.meta['item']
        item['title'] = hxs.select('//..../text()').extract()[0]
        item['content'] = hxs.select('//..../text()').extract()[0]
        yield item

Answer 1

Несколько вопросов здесь.

Основная проблема заключается в недопустимых выражениях внутри select() звонки.

Помимо этого:

• использование response.xpath() или же response.css() нет необходимости HtmlXPathSelector больше не
• нет необходимости создавать экземпляр Item экземпляр в parse() перезвонить и пройти meta, Получить URL от response.url в parse_listing_page() Перезвоните

Улучшен рабочий код:

import urlparse

from scrapy.spider import BaseSpider
from scrapy.http.request import Request

from scrapy_demo.items import ScrapyDemoItem


class ScrapyDemoSpider(BaseSpider): 
    name = "scrapy_demo"
    allowed_domains = ["buffalo.craigslist.org"]
    start_urls = ['http://buffalo.craigslist.org/search/cps/']

    def parse(self, response):
        # processing listings
        for listing in response.css('p.row > a[data-id]'):
            link = listing.xpath('@href').extract()[0]
            yield Request(urlparse.urljoin(response.url, link), callback=self.parse_listing_page)

        # following next page
        next_page = response.xpath('//a[contains(@class, "next")]/@href').extract()
        print next_page
        if next_page:
            yield Request(urlparse.urljoin(response.url, next_page[0]), callback=self.parse)

    def parse_listing_page(self, response):
        item = ScrapyDemoItem()
        item['link'] = response.url
        item['title'] = response.xpath('//title/text()').extract()[0].strip()
        item['content'] = response.xpath('//section[@id="postingbody"]/text()').extract()[0].strip()
        yield item

Если вы запустите spider, то в выходном файле JSON вы увидите:

[
    {"content": "Using a web cam with your computer to video communicate with your loved ones has never been made easier and it's free (providing you have an Internet connection).  With the click of a few buttons, you are sharing your live video and audio with the person you are communicating with. It's that simple.  When you are seeing and hearing your grand kids live across the country or halfway around the world, web camming is the next best thing to being there!", "link": "http://buffalo.craigslist.org/cps/4784390462.html", "title": "Web Cam With Your Computer With Family And Friends"},
    {"content": "Looking to supplement or increase your earnings?", "link": "http://buffalo.craigslist.org/cps/4782757517.html", "title": "1k in 30 Day's"},
    {"content": "Like us on Facebook: https://www.facebook.com/pages/NFB-Systems/514380315268768", "link": "http://buffalo.craigslist.org/cps/4813039886.html", "title": "NFB SYSTEMS COMPUTER SERVICES + WEB DESIGNING"},
    {"content": "Like us on Facebook: https://www.facebook.com/pages/NFB-Systems/514380315268768", "link": "http://buffalo.craigslist.org/cps/4810219714.html", "title": "NFB Systems Computer Repair + Web Designing"},
    {"content": "I can work with you personally and we design your site together (no outsourcing or anything like that!) I'll even train you how to use your brand new site. (Wordpress is really easy to use once it is setup!)", "link": "http://buffalo.craigslist.org/cps/4792628034.html", "title": "I Make First-Class Wordpress Sites with Training"},
    ...
]