22-爬虫之scrapy框架分布式09

分布式

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实现分布式的方式：scrapy+redis（scrapy结合着scrapy-redis组件）
原生的scrapy框架是无法实现分布式的
- 什么是分布式
  - 需要搭建一个分布式机群，然后让机群中的每一台电脑执行同一组程序，让其对同一组资源进行联合且分布的数据爬取。
  - 因调度器，管道无法被分布式机群共享所以原生架构scrapy无法实现分布式
  - 使用scrapy-redis组件可以给原生的scrapy框架提供共享管道和调度器实现分布式
    - pip install scrapy-redis

实现流程

创建工程

创建一个爬虫工程：scrapy startproject proName
进入工程创建一个基于CrawlSpider的爬虫文件
scrapy genspider -t crawl spiderName www.xxx.com
执行工程：scrapy crawl spiderName

1，修改爬虫文件

1.1 导包：from scrapy_redis.spiders import RedisCrawlSpider
1.2 修改当前爬虫类的父类为：RedisCrawlSpider
1.3 将start_url 替换成redis_key的属性，属性值为任意字符串
- redis_key=‘xxxx’ #可以被共享的调度器队列的名称/稍后我们需要将一个起始url手动添加到redis_key表示的队列中
1.4 将数据解析的操作补充完成即可

fbs.py 爬虫源文件

import scrapy
from scrapy.linkextractors import LinkExtractor
from scrapy.spiders import CrawlSpider, Rule
from scrapy_redis.spiders import RedisCrawlSpider
from fbsPro.items import FbsproItem

class FbsSpider(RedisCrawlSpider):
    name = 'fbs'
    #allowed_domains = ['www.xxx.com']
    #start_urls = ['http://www.xxx.com/']
    redis_key = 'sunQueue' #可以被共享的调度器队列的名称
    # 稍后我们需要将一个起始url手动添加到redis_key表示的队列中

    rules = (
        Rule(LinkExtractor(allow=r'id=1&page=d+'), callback='parse_item', follow=True),
    )

    def parse_item(self, response):
        # 将全站的标题获取
        li_list = response.xpath('/html/body/div[2]/div[3]/ul[2]/li')
        for li in li_list:
            title = li.xpath('./span[3]/a/text()').extract_first()
            item = FbsproItem()
            item['title']=title
            yield item

2，对settings.py进行配置

指定调度器

# 使用scrapy-redis组件的去重队列
DUPEFILTER_CLASS = "scrapy_redis.dupefilter.RFPDupeFilter"
# 使用scrapy-redis组件自己的调度器
SCHEDULER = "scrapy_redis.scheduler.Scheduler"
# 是否允许暂停
SCHEDULER_PERSIST = True

指定管道

#开启使用scrapy-redis组件中封装好的管道
ITEM_PIPELINES = {
    'scrapy_redis.pipelines.RedisPipeline': 400
} # 该种管道只可以将item写入redis

指定redis

#在配置文件中进行爬虫程序链接redis的配置：

REDIS_HOST = '127.0.0.1'
REDIS_PORT = 6379
# REDIS_ENCODING = 'utf-8'
# REDIS_PARAMS = {'password':'123456'}

完整代码

# Scrapy settings for fbsPro 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 = 'fbsPro'

SPIDER_MODULES = ['fbsPro.spiders']
NEWSPIDER_MODULE = 'fbsPro.spiders'
#LOG_LEVEL = 'ERROR' #指定类型日志的输出(只输出错误信息)

#设置UA伪装
USER_AGENT = 'Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/83.0.4103.97 Safari/537.36'

# Obey robots.txt rules
#改成False不遵从robots协议
ROBOTSTXT_OBEY = False

# 使用scrapy-redis组件的去重队列
DUPEFILTER_CLASS = "scrapy_redis.dupefilter.RFPDupeFilter"
# 使用scrapy-redis组件自己的调度器
SCHEDULER = "scrapy_redis.scheduler.Scheduler"
# 是否允许暂停
SCHEDULER_PERSIST = True

#开启使用scrapy-redis组件中封装好的管道
ITEM_PIPELINES = {
    'scrapy_redis.pipelines.RedisPipeline': 400
}

#在配置文件中进行爬虫程序链接redis的配置：

REDIS_HOST = '127.0.0.1'
REDIS_PORT = 6379
# REDIS_ENCODING = 'utf-8'
# REDIS_PARAMS = {'password':'123456'}


# Configure maximum concurrent requests performed by Scrapy (default: 16)
CONCURRENT_REQUESTS = 5

# 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 = {
#    'fbsPro.middlewares.FbsproSpiderMiddleware': 543,
#}

# Enable or disable downloader middlewares
# See https://docs.scrapy.org/en/latest/topics/downloader-middleware.html
#DOWNLOADER_MIDDLEWARES = {
#    'fbsPro.middlewares.FbsproDownloaderMiddleware': 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 = {
#    'fbsPro.pipelines.FbsproPipeline': 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'

3，配置redis的配置文件redis.windows.conf

解除默认绑定
- #bind 127.0.0.1 注释掉（第56行）
关闭保护模式
- protected-mode no 把yes改成no（第75行）
redis运行时出错
Creating Server TCP listening socket 127.0.0.1:6379: bind: No error
解决方法，依次输入以下命令
- redis-cli.exe
- shutdown
- exit
- redis-server redis.windows.conf
启动redis服务和客户端
- redis-server redis.windows.conf
redis-cli

5 执行scrapy工程

不要在配置文件中加入#LOG_LEVEL = ‘ERROR’
工程启动后程序回停留在listening位置，等待其实url的加入

6 想redis_key表示的队列中添加起始url

需要在redis的客户端执行如下指令：（调度器队列式存在与redis中）
lpush sunQueue http://wz.sun0769.com/political/index/politicsNewest?id=1&page=

我们查看数据库可以看见爬取到的数据
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