平时爬虫一般都使用Scrapy框架，通常都是在一台机器上跑，爬取速度也不能达到预期效果，数据量小，而且很容易就会被封禁IP或者账号，这时候可以使用代理IP或者登录方式爬，然而代理IP很多时候都很鸡肋，除非使用付费版IP，但是和真实IP差别很大。这时候便有了Scrapy-redis分布式爬虫框架，它基于Scrapy改造，把Scrapy的调度器（scheduler）换成了Scrapy-redis的调度器，可以轻松达到目的，利用多台服务器来爬取数据，而且还可以自动去重，效率高。爬取的数据默认保存在redis缓存中，速度很快。

Scrapy工作原理：

Scrapy-redis工作原理：

中间的就是调度器

豆瓣电影简易分布式爬虫

我这里直接使用start_urls的方式，数据存入到Mysql中

class DoubanSpider(RedisSpider):

    name = 'douban'

    redis_key = 'douban:start_urls'

    allowed_domains = ['douban.com']

    def start_requests(self):

        urls = get_urls()

        for url in urls:

            yield scrapy.Request(url=url, callback=self.parse)

    def parse(self, response):

        # item_loader = MovieItemLoader(item=MovieItem, response=response)

        #

        # item_loader.add_xpath('title', '')

        item = MovieItem()

        print(response.url)

        item['movieId'] = int(response.url.split('subject/')[1].replace('/', ''))

        item['title'] = response.xpath('//h1/span/text()').extract()[0]

        item['year'] = response.xpath('//h1/span/text()').extract()[1].split('(')[1].split(')')[0] or '2019'

        item['url'] = response.url

        item['cover'] = response.xpath('//a[@class="nbgnbg"]/img/@src').extract()[0]

        try:

            item['director'] = response.xpath('//a[@rel="v:directedBy"]/text()').extract()[0] or '无'

        except Exception:

            item['director'] = '暂无'

        item['major'] = '/'.join(response.xpath('//a[@rel="v:starring"]/text()').extract())

        item['category'] = ','.join(response.xpath('//span[@property="v:genre"]/text()').extract())

        item['time'] = ','.join(response.xpath('//span[@property="v:initialReleaseDate"]/text()').extract())

        try:

            item['duration'] = response.xpath('//span[@property="v:runtime"]/text()').extract()[0]

        except Exception:

            item['duration'] = '暂无'

        item['score'] = response.xpath('//strong[@property="v:average"]/text()').extract()[0]

        item['comment_nums'] = response.xpath('//span[@property="v:votes"]/text()').extract()[0] or 0

        item['desc'] = response.xpath('//span[@property="v:summary"]/text()').extract()[0].strip()

        actor_list = response.xpath('//ul[@class="celebrities-list from-subject __oneline"]/li/a/@title').extract()

        actor_img_list = response.xpath('//ul[@class="celebrities-list from-subject __oneline"]/li/a/div/@style').extract()

        actor_img_list = [i.split('url(')[1].replace(')', '') for i in actor_img_list]

        item['actor_name_list'] = '----'.join(actor_list)

        item['actor_img_list'] = '----'.join(actor_img_list)

        yield item

settings.py文件

BOT_NAME = 'MovieSpider'

SPIDER_MODULES = ['MovieSpider.spiders']

NEWSPIDER_MODULE = 'MovieSpider.spiders'

# REDIS_HOST = '127.0.0.1'

# REDIS_PORT = 6379

REDIS_URL = 'redis://username:password@xxx.xxx.xxx.xxx:6379'

# Obey robots.txt rules

ROBOTSTXT_OBEY = False

SCHEDULER = "scrapy_redis.scheduler.Scheduler"

# Ensure all spiders share same duplicates filter through redis.

DUPEFILTER_CLASS = "scrapy_redis.dupefilter.RFPDupeFilter"

ITEM_PIPELINES = {

    'scrapy_redis.pipelines.RedisPipeline': 300,

    'MovieSpider.pipelines.MysqlPipeline': 200,

}

这里只是为了多台服务器一起爬取，没有手动在redis中推入起始的URL

此时将爬虫项目上传到其他服务器上，一起开始

效果如下：