爬虫————获取图片（scrapy使用自带类 ImagesPipeline）

爬取的图片网址为：http://699pic.com/collectInfo/273785

解决问题的参考链接：https://blog.csdn.net/loner_fang/article/details/81111879

问题代码1

imgpro.py

# -*- coding: utf-8 -*-
import scrapy

from tupian.items import TupianItem
from scrapy.selector.unified import SelectorList


class ImgproSpider(scrapy.Spider):
    name = 'imgpro'
    #allowed_domains = ['699pic.com']
    start_urls = ['http://699pic.com/collectInfo/273785']

    def parse(self, response):
        li_ul = response.xpath('/html/body/div[11]/div/ul')
 #       print(type(li_ul))
        for li in li_ul :
            img_src = li.xpath('./li/a/img/@src').extract()
           # print(img_src)
            if img_src:
                item = TupianItem()
                item['src'] = img_src
                yield  item

pipeline.py

# -*- coding: utf-8 -*-

# 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


# class TupianPipeline(object):
#     def process_item(self, item, spider):
#         return item

from scrapy.pipelines.images import ImagesPipeline
import scrapy

class TupianPipeline(ImagesPipeline):

    # 对某一个媒体资源进行请求发送
    # item就是接收到的spider提交过来的item
    def get_media_requests(self, item, info):

       23             yield scrapy.Request(item['src'])

        #制定媒体数据存储的名称/html/body/div[11]/div/ul          /html/body/div[11]/div/ul
    def file_path(self, request, response=None, info=None):
        name = request.url.split('/')[-1]
        print("正在下载。。。。。。。",name)
        return name

   #将item传递给下一个即将执行的管道类
    def item_completed(self, results, item, info):
        return item

错误类型

分析错误原因：

1、在写爬虫文件解析response时，获取图片的下载地址，一开始写的xpath是@src

 修改后为下图所示     

后来排查代码，观察网页源代码，发现源代码中@src的值是http://static.699pic.com/images/blank.png。刚才element中的src是经过渲染之后的值，所以最后采用的@data-original。这也就证实了爬虫获取到的response是网页的源码，爬取之前需要先确认源码和element中的元素和值是否一致，只有一致了才可以直接使用element中的元素和值。

 2、遍历image_urls里的每一个url，调用调度器和下载器，下载图片 。 图片下载完毕后，处理结果会以二元组的方式返回给item_completed()函数

错误点为下图

修改后为下图

# -*- coding: utf-8 -*-
import scrapy

from tupian.items import TupianItem
from scrapy.selector.unified import SelectorList


class ImgproSpider(scrapy.Spider):
    name = 'imgpro'
    #allowed_domains = ['699pic.com']
    start_urls = ['http://699pic.com/collectInfo/273785']

    def parse(self, response):
        li_ul = response.xpath('/html/body/div[11]/div/ul')
 #       print(type(li_ul))
        for li in li_ul :
            img_src = li.xpath('./li/a/img/@data-original').extract()
           # print(img_src)
            if img_src:
                item = TupianItem()
                item['src'] = img_src
                yield  item

# -*- coding: utf-8 -*-

# 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


# class TupianPipeline(object):
#     def process_item(self, item, spider):
#         return item

from scrapy.pipelines.images import ImagesPipeline
import scrapy

class TupianPipeline(ImagesPipeline):

    # 对某一个媒体资源进行请求发送
    # item就是接收到的spider提交过来的item
    def get_media_requests(self, item, info):

        for image_url in item['src']:
            yield scrapy.Request(image_url)

        #制定媒体数据存储的名称/html/body/div[11]/div/ul          /html/body/div[11]/div/ul
    def file_path(self, request, response=None, info=None):
        name = request.url.split('/')[-1]
        print("正在下载。。。。。。。",name)
        return name

   #将item传递给下一个即将执行的管道类
    def item_completed(self, results, item, info):
        return item

# -*- coding: utf-8 -*-

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

import scrapy


class TupianItem(scrapy.Item):
    # define the fields for your item here like:
    # name = scrapy.Field()
    src = scrapy.Field()

# -*- coding: utf-8 -*-

# Scrapy settings for tupian 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 = 'tupian'

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


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

# Obey robots.txt rules
ROBOTSTXT_OBEY = False

LOG_LEVEL = 'ERROR'

IMAGES_STORE = './imgsLib'

# 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 6.1; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/77.0.3865.120 Safari/537.36'

}

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

# Enable or disable downloader middlewares
# See https://docs.scrapy.org/en/latest/topics/downloader-middleware.html
#DOWNLOADER_MIDDLEWARES = {
#    'tupian.middlewares.TupianDownloaderMiddleware': 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 = {
   # 'scrapy.pipelines.images.ImagesPipeline': 1,
   'tupian.pipelines.TupianPipeline': 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'