使用scrapy中的items、piplines、settings
作者：互联网
bookstoscrape
1 import scrapy
2 from spider_01_books.items import BookItem
3
4 class BookstoscrapeSpider(scrapy.Spider):
5 """爬虫类，继承spider"""
6 #爬虫名称--每一个爬虫的唯一标识
7 name = 'bookstoscrape'
8 #允许爬爬取的域名
9 allowed_domains = ['books.toscrape.com']
10 #初始爬取的URL
11 start_urls = ['http://books.toscrape.com/']
12 #解析下载
13 def parse(self, response):
14 #提取数据
15 #每一本书的信息在<article class="product_pod">中，使用xpath()方法找到所有的article元素，并依次迭代
16 for book in response.xpath('//article[@class="product_pod"]'):
17 # #书名信息在article>h3 >a元素的title属性中
18 #创建item对象
19 item = BookItem()
20 #例如：<a href="catalogue/a-light-in-the-attic_1000/index.html" title="A Light in the Attic">A Light in the ...</a>
21 item['name'] = book.xpath('./h3/a/@title').extract_first()
22 # extract_first()：这个方法返回的是一个string字符串，是list数组里面的第一个字符串。
23 #书价信息在article><div class="product_price">的text中，例如：<p class="price_color">£51.77</p>
24 item['price']= book.xpath('./div[2]/p[1]/text()').extract_first()[1:]
25 #书的评级在article>p 元素的class属性中。例如：<p class="star-rating Three">
26 item['rate'] = book.xpath('./p/@class').extract_first().split(" ")[1]
27
28 #返回单个图书对象
29 yield item
30 #提取下一页的链接
31 #下一页的url在li.next >a 元素的href属性中
32 #例如：<li class="next"><a href="catalogue/page-2.html">next</a></li>
33 next_url= response.xpath('//li[@class="next"]/a/@href').extract_first()
34
35 #判断
36 if next_url:
37 #如果找到下一页的URl，则得到绝对路径，构造新的request对象
38 next_url = response.urljoin(next_url)
39 #返回新的request对象
40 yield scrapy.Request(next_url,callback=self.parse)
items：
# Define here the models for your scraped items
#
# See documentation in:
# https://docs.scrapy.org/en/latest/topics/items.html
import scrapy
class BookItem(scrapy.Item):
# define the fields for your item here like:
#可以设置自己想要的格式，设置的名称和bookstoscrape中名字对应
name = scrapy.Field()
price = scrapy.Field()
rate = scrapy.Field()
piplines处理：
# Define your item pipelines here
#
# Don't forget to add your pipeline to the ITEM_PIPELINES setting
# See: https://docs.scrapy.org/en/latest/topics/item-pipeline.html
# useful for handling different item types with a single interface
from itemadapter import ItemAdapter
class PriceConverterPipeline(object):
"""实现英镑转人民币"""
# 英镑兑换人民币汇率 1英镑=8.7091人民币
exchange_rate = 8.7091
def process_item(self, item, spider):
"""处理传入的item,最后返回"""
# 提取item的price 字段（如￡53.74）
# 去掉前面英镑符号￡，转换为float类型，乘以汇率
price = float(item['price'][1:]) * self.exchange_rate
# 保留2 位小数，赋值回item的price字段
item['price'] = '￥%.2f' % price
# 必须返回item
return item
settings 设置：
# Scrapy settings for spider_01_books project
#
# For simplicity, this file contains only settings considered important or
# commonly used. You can find more settings consulting the documentation:
#
# https://docs.scrapy.org/en/latest/topics/settings.html
# https://docs.scrapy.org/en/latest/topics/downloader-middleware.html
# https://docs.scrapy.org/en/latest/topics/spider-middleware.html
BOT_NAME = 'spider_01_books'
SPIDER_MODULES = ['spider_01_books.spiders']
NEWSPIDER_MODULE = 'spider_01_books.spiders'
# Crawl responsibly by identifying yourself (and your website) on the user-agent
#USER_AGENT = 'spider_01_books (+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://docs.scrapy.org/en/latest/topics/settings.html#download-delay
# See also autothrottle settings and docs
#DOWNLOAD_DELAY = 3
# 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://docs.scrapy.org/en/latest/topics/spider-middleware.html
#SPIDER_MIDDLEWARES = {
# 'spider_01_books.middlewares.Spider01BooksSpiderMiddleware': 543,
#}
# Enable or disable downloader middlewares
# See https://docs.scrapy.org/en/latest/topics/downloader-middleware.html
#DOWNLOADER_MIDDLEWARES = {
# 'spider_01_books.middlewares.Spider01BooksDownloaderMiddleware': 543,
#}
# Enable or disable extensions
# See https://docs.scrapy.org/en/latest/topics/extensions.html
#EXTENSIONS = {
# 'scrapy.extensions.telnet.TelnetConsole': None,
#}
# Configure item pipelines
# See https://docs.scrapy.org/en/latest/topics/item-pipeline.html
ITEM_PIPELINES = {
'spider_01_books.pipelines.PriceConverterPipeline': 300,
}
# Enable and configure the AutoThrottle extension (disabled by default)
# See https://docs.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://docs.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'
标签：en,items,spider,piplines,item,scrapy,html,docs 来源： https://www.cnblogs.com/anhao-world/p/16328834.html