从 xml 文件中抓取 url 并抓取这些 url

Question

所以我在 items.py 文件中声明了一个名为 ArtscraperItem 的项目。

import scrapy


class ArtscraperItem(scrapy.Item):
    # define the fields for your item here like:
    # name = scrapy.Field()
    date = scrapy.Field()
    date_str = scrapy.Field()
    url = scrapy.Field()
    title = scrapy.Field()
    art_content = scrapy.Field()

我是运行这个蜘蛛，正在从 xml 文件中收集数据。但是，我还需要从 xml 文件中获取 urls，然后抓取那些 urls 以获取文章的内容并将其添加为项目 [art_content ].我在 Whosebug 上看到了类似的东西，但他们没有使用以前声明的项目，所以我不知道如何使用它。因此，我需要从我抓取的 url 中获取内容并将其添加到我在解析方法中创建的 ArtscraperItem。

提前致谢。

有问题的方法和第二种 parse_article 方法应该抓取收集的 url 和 return 文章内容。

from datetime import datetime as dt
import scrapy
from ArtScraper.items import ArtscraperItem

class PostSpider(scrapy.Spider):
    article = ""
    name = 'crawly'
    allowed_domains = ['bbc.com/arabic']

    start_urls = ['http://feeds.bbci.co.uk/arabic/rss.xml']

    def parse(self, response):
        articles = response.xpath('//channel/item')
        for article in articles:
            item = ArtscraperItem()
            item['date']= dt.today()
            item['date_str'] = article.xpath('pubDate/text()').extract_first()
            item['url'] = article.xpath('link/text()').extract_first()
            item['title'] = article.xpath('title/text()').extract_first()
            url = item['url']
            yield scrapy.Request(url, callback=self.parse_article)
            yield item

    def parse_article(self, response):
        pars = response.xpath("//div[@class='story-body']/div[@class='story-body__inner']/p/text()").extract()
        article = '-'.join(pars)
        yield{
            'art_content': article
        }

settings.py 文件

#Settings.py

BOT_NAME = 'ArtScraper'

SPIDER_MODULES = ['ArtScraper.spiders']
NEWSPIDER_MODULE = 'ArtScraper.spiders'


# Crawl responsibly by identifying yourself (and your website) on the 
user-agent
#USER_AGENT = 'ArtScraper (+http://www.yourdomain.com)'

# Obey robots.txt rules
ROBOTSTXT_OBEY = True

# Configure maximum concurrent requests performed by Scrapy (default: 
16)
#CONCURRENT_REQUESTS = 32

# Configure a delay for requests for the same website (default: 0)
# See https://doc.scrapy.org/en/latest/topics/settings.html#download- 
delay
# See also autothrottle settings and docs
DOWNLOAD_DELAY = .25
RANDOMIZE_DOWNLOAD_DELAY=True
# The download delay setting will honor only one of:
#CONCURRENT_REQUESTS_PER_DOMAIN = 16
#CONCURRENT_REQUESTS_PER_IP = 16

# Disable cookies (enabled by default)
#COOKIES_ENABLED = False

# Disable Telnet Console (enabled by default)
#TELNETCONSOLE_ENABLED = False

# Override the default request headers:
#DEFAULT_REQUEST_HEADERS = {
#   'Accept': 
'text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8',
#   'Accept-Language': 'en',
#}

# Enable or disable spider middlewares
# See https://doc.scrapy.org/en/latest/topics/spider-middleware.html
#SPIDER_MIDDLEWARES = {
#    'ArtScraper.middlewares.ArtscraperSpiderMiddleware': 543,
#}

# Enable or disable downloader middlewares
# See https://doc.scrapy.org/en/latest/topics/downloader- 
middleware.html
#DOWNLOADER_MIDDLEWARES = {
#    'ArtScraper.middlewares.ArtscraperDownloaderMiddleware': 543,
#}

# Enable or disable extensions
# See https://doc.scrapy.org/en/latest/topics/extensions.html    
#EXTENSIONS = {
#    'scrapy.extensions.telnet.TelnetConsole': None,
#}

# Configure item pipelines
# See https://doc.scrapy.org/en/latest/topics/item-pipeline.html
ITEM_PIPELINES = {
'ArtScraper.pipelines.MongoPipeline': 300,  
}
MONGO_URI='localhost:27017'
MONGO_DATABASE='george'

#Enable and configure the AutoThrottle extension (disabled by default)
# See https://doc.scrapy.org/en/latest/topics/autothrottle.html
#AUTOTHROTTLE_ENABLED = True
# The initial download delay
#AUTOTHROTTLE_START_DELAY = 5
# The maximum download delay to be set in case of high latencies
#AUTOTHROTTLE_MAX_DELAY = 60
# The average number of requests Scrapy should be sending in parallel 
to
# each remote server
#AUTOTHROTTLE_TARGET_CONCURRENCY = 1.0
# Enable showing throttling stats for every response received:
#AUTOTHROTTLE_DEBUG = False

# Enable and configure HTTP caching (disabled by default)
# See https://doc.scrapy.org/en/latest/topics/downloader- 
middleware.html#httpcache-middleware-settings
#HTTPCACHE_ENABLED = True
#HTTPCACHE_EXPIRATION_SECS = 0
#HTTPCACHE_DIR = 'httpcache'
#HTTPCACHE_IGNORE_HTTP_CODES = []
#HTTPCACHE_STORAGE = 
'scrapy.extensions.httpcache.FilesystemCacheStorage'

pipelines.py 文件

import logging
import pymongo

class MongoPipeline(object):

collection_name = 'articles'

def __init__(self, mongo_uri, mongo_db):
    self.mongo_uri = mongo_uri
    self.mongo_db = mongo_db

@classmethod
def from_crawler(cls, crawler):
    ## pull in information from settings.py
    return cls(
        mongo_uri=crawler.settings.get('MONGO_URI'),
        mongo_db=crawler.settings.get('MONGO_DATABASE')
    )

def open_spider(self, spider):
    ## initializing spider
    ## opening db connection
    self.client = pymongo.MongoClient(self.mongo_uri)
    self.db = self.client[self.mongo_db]

def close_spider(self, spider):
    ## clean up when spider is closed
    self.client.close()

def process_item(self, item, spider):
    ## how to handle each post
    self.db[self.collection_name].insert(dict(item))
    logging.debug("Post added to MongoDB")
    return item

Answer 1

这称为请求链接和元结转。
您有 2 个请求制作 1 个项目，因此您需要：

转到url A，收集一些数据
转到url B，添加更多数据
Return 包含来自 A 和 B 的数据的单个项目

到link这两步你可以使用Request.meta属性，像这样：

def parse(self, response):
    articles = response.xpath('//channel/item')
    for article in articles:
        item = ArtscraperItem()
        ...
        yield scrapy.Request(
            url, 
            callback=self.parse_article,
            meta={'item': item},  # carry over our item
        )

def parse_article(self, response):
    # retrieve carried over item
    item = response.meta['item']
    pars = response.xpath("//div[@class='story-body']/div[@class='story-body__inner']/p/text()").extract()
    item['art_content'] = '-'.join(pars)
    yield item

从 xml 文件中抓取 url 并抓取这些 url

Scraping urls from xml file and scraping those urls

python

scrapy

web-scraping

scrapy-spider