scrapy爬虫-scrapy-redis分布式

1、如何将一个scrapy爬虫项目修改成为一个简单的分布式爬虫项目

官方文档：https://scrapy-redis.readthedocs.io/en/stable/

只用修改scrapy项目的两个文件就可以了

一个是爬虫组件文件# -*- coding: utf-8 -*-

 scrapy
from scrapy_redis.spiders import RedisSpider


# 自定义爬虫类的继承类不再是scrapy.spiders下面的爬虫类，
# 而是scrapy-redis.spiders下面的爬虫类
class DistributedSpiderSpider(RedisSpider):
    name = 'distributed_spider'
    allowed_domains = ['wh.lianjia.com']
    # 将start_urls替换为redis_key
    # start_urls = ['https://wh.lianjia.com/ershoufang/']

    # redis_key在数据库中是列表类型，所以需要使用列表的语法添加
    redis_key = "myspider:start_urls"

    def parse(self, response):
        print(response.meta)
        item = dict()
        item["province"] = "湖北"
        item["city"] = "武汉"
        blocks = response.xpath("//div[@class='position']/dl[2]/dd/div[1]/div/a")
        for block in blocks:
            title = blocks.xpath("./@title").get()
            url = "https://wh.lianjia.com" + block.xpath("./@href").get()

            print(title, url, "=====================================")

            yield scrapy.Request(url=url, callback=self.parse_block, meta={"item": item})

    def parse_block(self, response):
        print(response.meta)
        url = response.url + "pg%dco32/"
        index = 1
        while index < 100:
            new_url = url % index
            print(new_url)
            yield scrapy.Request(url=new_url, callback=self.parse_item, meta={"item": response.meta["item"]})
            index += 1

    def parse_item(self, response):
        print(response.meta)
        sellLinks = response.css("ul.sellListContent>li>a")
        for link in sellLinks:
            url = link.xpath("./@href").get()
            print(url)
            yield scrapy.Request(url=url, callback=self.parse_detail, meta={"item": response.meta["item"]})

    def parse_detail(self, response):
        item = response.meta["item"]
        print(response.meta)
        item["url"] = response.url
        item["block"] = response.css("div.areaName>span.info").xpath("./a[1]/text()").get().strip()
        item["smallBlock"] = response.css("div.areaName>span.info").xpath("./a[2]/text()").get().strip()
        item["price"] = response.xpath("//span[@class='total']/text()").get().strip() + "万"
        item["unitPrice"] = response.xpath("//span[@class='unitPriceValue']/text()").get().strip() + "元/平米"
        print(item)

另一个是设置文件（settings.py）:

在设置文件中添加几个设置项就可以了

SCHEDULER = "scrapy_redis.scheduler.Scheduler"
# hash + set
DUPEFILTER_CLASS = "scrapy_redis.dupefilter.RFPDupeFilter"

ITEM_PIPELINES = {
   'DistributedSpider.pipelines.DistributedspiderPipeline': 300,
   'scrapy_redis.pipelines.RedisPipeline': 400
}

REDIS_HOST = "localhost"  # 要连接的redis数据库的地址

REDIS_PORT = "6379"  # redis数据库启动时的默认端口

# 默认是db0(redis有16个数据库，从db0~db15

# 如果远程redis数据库设置了密码，需要加下面一项
REDIS_PARAMS = {
　　"password": "********"
}