實質上就是在多個機器上運行爬蟲文件,調用組件scrapy_redis實現共享調度器和管道,寫入redis數據庫的過程。
分佈式爬取的流程:
https://www.cnblogs.com/foremostxl/p/10095663.html#_label1
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安裝scrapy-redis組件,
pip install scrapy-redis
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redis配置文件的設置:
bind 127.0.0.1 只允許本機鏈接,註釋掉
protected-mode no 關閉保護模式
打開redis終端 -
創建基於crawlspider的爬蟲文件
scrapy startproject redispro
cd redispro
scrapy genspider -t qiubai https://www.qiushibaike.com/pic/ -
導入類
from scrapy_redis.spiders import RedisCrawlSpider
,修改繼承類class QiubaiSpider(RedisCrawlSpider):
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start_urls 註釋改爲redis_key,
redis_key='qiubaispider'
,字符串qiubaispider
表示調度器中隊列的名稱,基於RedisCrawlSpider。 -
settings配置文件修改
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運行:切換到爬蟲py文件所在的目錄,比之前運行項目的目錄更深,
scrapy runspider xxx.py
運行py文件後, -
在redis客戶端放入redis_key對應的url
lpush 調度器隊列的名稱 “起始url”
redis客戶端發送lpush時名稱和redis_key要一致
redis_key=‘qiubaispider’
lpush qiubaispider https://www.qiushibeike.com/pic -
結果查看:
lrange qiubai:items
代碼:
import scrapy
from scrapy.linkextractors import LinkExtractor
from scrapy.spiders import CrawlSpider, Rule
from scrapy_redis.spiders import RedisCrawlSpider
from redispro.items import RedisproItem
class QiubaiSpider(RedisCrawlSpider):
name = 'qiubai'
# allowed_domains = ['https://www.qiushibaike.com/pic/']
# start_urls = ['https://www.qiushibaike.com/pic//']
redis_key='qiubaispider'
rules = (
Rule(LinkExtractor(allow=r'/pic/page/\d+'), callback='parse_item', follow=True),
)
def parse_item(self, response):
div_list=response.xpath('//div[@id="content-left"]/div')
for div in div_list:
# 相對於div_list .// img_url
img_url ="https:" + div.xpath('.//div[@class="thumb"]/a/img/@src').extract_first()
item = RedisproItem()
item['img_url'] = img_url
yield item
import scrapy
class RedisproItem(scrapy.Item):
# define the fields for your item here like:
# name = scrapy.Field()
img_url=scrapy.Field()
BOT_NAME = 'redispro'
SPIDER_MODULES = ['redispro.spiders']
NEWSPIDER_MODULE = 'redispro.spiders'
# 以下是加上去的:
USER_AGENT = 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/73.0.3683.75 Safari/537.36'
LOG_LEVEL = 'ERROR'
LOG_FILE = 'log.txt'
# Obey robots.txt rules
ROBOTSTXT_OBEY = False
# 使用組件管道
ITEM_PIPELINES = {
'scrapy_redis.pipelines.RedisPipeline': 300,
}
# 去重
DUPEFILTER_CLASS = "scrapy_redis.dupefilter.RFPDupeFilter"
# 使用scrapy_redis組件的調度器
SCHEDULER = "scrapy_redis.scheduler.Scheduler"
# 是否允許暫停,某臺機器出現故障時會從暫停之前的位置開始
SCHEDULER_PERSIST = True
# 配置redis服務器,爬蟲文件在其他電腦上運行。
REDIS_HOST = redis服務端地址
REDIS_PORT = 6379