爬虫_scrapy_当当网爬取数据

2022-05-30 16:33:44 阅读：144 来源： 互联网

标签：self 当当网爬取 item scrapy html https dangdang

1.创建项目

scrapy startproject scrapy_dangdang

2.创建一个爬虫文件

爬取地址：http://category.dangdang.com/cp01.01.02.00.00.00.html

scrapy genspider dang http://category.dangdang.com/cp01.01.02.00.00.00.html

3.各部分代码

dang.py文件

import scrapy
from scrapy_dangdang.items import ScrapyDangdangItem

class DangSpider(scrapy.Spider):
    name = 'dang'
    # 多页请求一般情况下只写域名
    allowed_domains = ['category.dangdang.com']
    start_urls = ['http://category.dangdang.com/cp01.01.02.00.00.00.html']

    base_url='http://category.dangdang.com/pg'
    page = 1

    def parse(self, response):
        # pipelines 下载数据
        # items 定义数据结构的
        # src='//ul[@id="component_59"]/li//img/@src'
        # alt='//ul[@id="component_59"]/li//img/@alt'
        # price='//ul[@id="component_59"]/li//p[@class="price"]/span[1]/text()'
        # 所有的selector的对象都可以再次调用xpath方法
        li_list = response.xpath('//ul[@id="component_59"]/li')

        print('=====================获取数据================================')
        for li in li_list:
            # 这里涉及到了图片的懒加载
            src = li.xpath('.//img/@data-original').extract_first()
            # 第一张图片和其他图片的标签的熟悉是不一样的
            # 第一张图片的src是可以使用的，其他的图片的地址是data-original
            if src:
                src = src
            else:
                src = li.xpath('.//img/@src').extract_first()
            name = li.xpath('.//img/@alt').extract_first()
            price = li.xpath('.//p[@class="price"]/span[1]/text()').extract_first()

            book = ScrapyDangdangItem(src=src,name=name,price=price)
            # 获取一个book就将book交给pipelines
            yield book

        #每一页爬取的业务逻辑都是一样的，所以我们只需要将执行的那个页的请求再次调用parse方法就可以了
        if self.page < 10:
            self.page = self.page + 1
            url = self.base_url+str(self.page)+'-cp01.01.02.00.00.00.html'
            # 调用parse方法
            # scrapy.Request就是scrapy的get请求
            yield scrapy.Request(url=url,callback=self.parse)

items.py文件

# Define here the models for your scraped items
#
# See documentation in:
# https://docs.scrapy.org/en/latest/topics/items.html

import scrapy


class ScrapyDangdangItem(scrapy.Item):
    # define the fields for your item here like:
    # name = scrapy.Field()
    # 通俗的说就是你要下载的数据都有什么
    # 图片
    src = scrapy.Field()
    # 名字
    name = scrapy.Field()
    # 价格
    price = scrapy.Field()
    pass

pipelines.py文件

# 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

# 如果想要使用管道的话，那么就必须在settings中开启管道
class ScrapyDangdangPipeline:
    # 在爬虫文件开始的之前就执行一个方法
    def open_spider(self,spider):
        self.fp = open('book.json','w',encoding='utf-8')

    # item就是yield后面的book对象
    def process_item(self, item, spider):
        # 以下这种模式不推荐，因为每传递过来一个对象，那么就打开一次文件，对文件的操作过于频繁
        # (1) write方法必须要写一个字符串，而不是其他的对象
        # (2)w模式会每一个对象都打开一次文件，覆盖之前的内容，所有用a模式
        # with open('book.json','a',encoding='utf-8')as fp:
        #     fp.write(str(item))

        self.fp.write(str(item))

        return item
    # 在爬虫文件执行完之后，执行的方法
    def close_spider(self,spider):
        self.fp.close()


import urllib.request
# 多条管道开启
# （1） 定义管道类(下载图片)
# （2）在settings中开启管道
class DangDangDownloadPipeline:
    def process_item(self,item,spider):
        url = 'http:'+item.get('src')
        filename = './books/'+item.get('name')+'.jpg'
        urllib.request.urlretrieve(url=url,filename=filename)

        return item

settings.py文件

# Scrapy settings for scrapy_dangdang 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 = 'scrapy_dangdang'

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


# Crawl responsibly by identifying yourself (and your website) on the user-agent
#USER_AGENT = 'scrapy_dangdang (+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 = {
#    'scrapy_dangdang.middlewares.ScrapyDangdangSpiderMiddleware': 543,
#}

# Enable or disable downloader middlewares
# See https://docs.scrapy.org/en/latest/topics/downloader-middleware.html
#DOWNLOADER_MIDDLEWARES = {
#    'scrapy_dangdang.middlewares.ScrapyDangdangDownloaderMiddleware': 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
# 开启管道
ITEM_PIPELINES = {
    # 管道可以有很多个，那么管道是有优先级的，优先级的范围是1到1000，值越小优先级越高
   'scrapy_dangdang.pipelines.ScrapyDangdangPipeline': 300,
   'scrapy_dangdang.pipelines.DangDangDownloadPipeline': 301
}

# 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'

代码地址：https://gitee.com/heating-cloud/python_spider.git

标签：self,当当网,爬取,item,scrapy,html,https,dangdang
来源： https://www.cnblogs.com/ckfuture/p/16327206.html

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爬虫_scrapy_当当网爬取数据

1.创建项目

2.创建一个爬虫文件