1.引言

爬取摄图网插画栏目中各个类目下的全部图片。

要求：将所有爬取的图片保存至以各自所属类别命名的文件夹中。

2.流程分析

首先这个任务属于一个两层网络爬虫，因为实际图片的下载路径位于第二层，所以我们必须从第一层网页中获取第二层网页的URL，接着从第二层网页中抓取各个图片的下载地址。

在这里插入图片描述

上图展示的网页是我们初始请求的网页，其中每个图片对应一个插画类目，共100多个类目；我们需要请求该网页，并抓取每个插画类目对应的URL。

在这里插入图片描述

在这里插入图片描述

进入到其中的开学季插画类目，利用CSS选择器定位到每张图片的下载地址，我们发现一共有100张图片。

根据以上的分析，我们的目标是爬取并下载120个插画类目下共12000张图片。

3.代码实现

• 新建项目

在终端分别输入以下命令行，新建爬虫项目。

scrapy startproject shetuwang

cd shetu
scrapy genspider picture 699pic.com 

• 编写items.py源文件，设定需要爬取的字段

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

import scrapy


class ShetuwangItem(scrapy.Item):
    title = scrapy.Field() #图片所属类别
    imgurls = scrapy.Field() #图片下载地址
    images = scrapy.Field() #图片信息
    
    # define the fields for your item here like:
    # name = scrapy.Field()
    #pass

• 编写picture.py源文件，制定爬虫的数据爬取工作

import scrapy
from scrapy import Request
from ..items import ShetuwangItem

class PictureSpider(scrapy.Spider):
    name = 'picture'
    allowed_domains = ['699pic.com']
    start_urls = ['http://699pic.com/chahua/']

    def parse(self, response):
        typeurls = response.css(".pl-list a::attr(href)").extract()
        for imgurl in typeurls:
            imgurl = 'https:'+imgurl
            yield Request(imgurl,callback=self.parse_image)
            
    def parse_image(self,response):
        item = ShetuwangItem()
        
        imageurls = response.css("div.list a img::attr(data-original)").extract()
        if imageurls:
            title = response.css("strong.Gjc::text").extract()[0]
            item['title'] = title
            
        imgurls = []
        for imageurl in imageurls:
            imageurl = 'https:' + imageurl
            imgurls.append(imageurl)
            
        item['imgurls'] = imgurls
        yield item

• 编写pipelines.py源文件，处理图片的下载与保存工作

# 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
from scrapy.pipelines.images import ImagesPipeline
from scrapy import Request

class ShetuwangPipeline:
    def process_item(self, item, spider):
        return item

class DownloadImagesPipeline(ImagesPipeline):
    def get_media_requests(self,item,info):
        for imgurl in item['imgurls']:
            yield Request(imgurl,meta={'title':item['title']})
            
    def file_path(self,request,response=None,info=None):
        title = request.meta['title']
        imgname = request.url.split('/')[-1]
        filename = u'{0}/{1}'.format(title,imgname)
        return filename
    
    def thumb_path(self,request,thumb_id,response=None,info=None):
        title = request.meta["title"]
        image_name = request.url.split("/")[-1]
        thumbname = u'{0}/{1}/{2}'.format(title,thumb_id,image_name)
        return thumbname

• 编写settings.py源文件，配置爬虫项目

# Scrapy settings for shetuwang 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 = 'shetuwang'

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


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

# Obey robots.txt rules
ROBOTSTXT_OBEY = False

# 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',
  'User-Agent': 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/92.0.4515.131 Safari/537.36 Edg/92.0.902.67',
}

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

# Enable or disable downloader middlewares
# See https://docs.scrapy.org/en/latest/topics/downloader-middleware.html
#DOWNLOADER_MIDDLEWARES = {
#    'shetuwang.middlewares.ShetuwangDownloaderMiddleware': 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 = {
   #'shetuwang.pipelines.ShetuwangPipeline': 300,
    'shetuwang.pipelines.DownloadImagesPipeline': 300,
}

IMAGES_STORE = 'D:\\scrapy\\shetuwang'
IMAGES_URLS_FIELD = 'image_urls'
IMAGES_RESULT_FIELD = 'images'
IMAGES_THUMBS = {'small':(80,80),'big':(300,300)}


# 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'

• 在终端用命令行运行爬虫，进行爬取

scrapy crawl picture

• 查看运行结果

在没有分布式爬取技术加持的情况下，12000张图片爬取下来需要较长时间，这里只展示爬取到的部分图片。

在这里插入图片描述

此刻只爬取完了两个类目，分别是开学季插画、微光渐变插画。

开学季

微光渐变

以上为微光渐变插画，及不同尺寸的缩略图。

3.更深入

通过查看下载的图片，我发现每张图片上都有水印；需要有摄图网账号，且注册会员才能下载无水印图片。

如果我已经满足了下载无水印图片的资质了，该如何改进这个项目，进行无水印图片的爬取呢？

欢迎大家来评论区交流意见！

写在最后

全套爬虫开发环境配置

人类之奴