分布式爬虫scrapy-redis的实战踩坑记录

目录

一、安装redis

1.首先要下载相关依赖

2.然后编译redis

二、scrapy框架出现的问题

1.AttributeError: TaocheSpider object has no attribute make_requests_from_url 原因:

2.ValueError: unsupported format character : (0x3a) at index 9 问题:

三、scrapy正确的源代码

1.items.py文件

2.settings.py文件

3.taoche.py文件

4.其余文件

总结

一、安装redis

因为是在CentOS系统下安装的,并且是服务器。遇到的困难有点多不过。

1.首先要下载相关依赖

首先先检查是否有c语言的编译环境,你问我问什么下载这个,我只能说它是下载安装redis的前提,就像水和鱼一样。

rpm -q gcc```

如果输出版本号,则证明下载好了,否则就执行下面的命令,安装gcc,

2.然后编译redis

下载你想要的redis版本注意下面的3.0.6是版本号,根据自己想要的下载版本号,解压

yum install gcc-c++ cd /usr/local/redis wget http://download.redis.io/releases/redis-3.0.6.tar.gz tar zxvf redis-3.0.6.tar.gz make && make install

什么?你问我没有redis文件夹怎么办,mkdir创建啊!!!

一定要先进入目录再去执行下载编译,这样下载的redis才会进入系统变量。

redis-server redis-cli

启动服务你是下面这样的吗?

是的就不正常了!!你才下载好了,你会发现你可以开启服务了,但是退不出来,无法进入命令行了,变成下面的这鬼摸样了,别急,你还没配置好,慢慢来。

还记得你刚刚创建的redis文件夹吗?进入那里面,找到redis.conf,修改这个配置文件。

redis-server redis-cli

找到这三个并改正。

首先将bind进行注释,因为如果不注释的话,你就只能本机访问了,我相信你下载肯定不只是自己访问吧。这就意味着所有ip都可以访问这个数据库,但你又问了,这会不会影响安全性能呢?答:你都是租的服务器了,就算你想让别人访问,你还有安全组规则限制的啊,你问我什么是安全组?快去百度!!

将守护模式关闭,这样你才能远程读写数据库

开启后台模式,你才能像我那样,而不是退不出来

保存退出,重启redis,这样,redis就配置好了,还可以设置密码,但是我懒,不想设置。

至此数据库配置成功

二、scrapy框架出现的问题 1.AttributeError: TaocheSpider object has no attribute make_requests_from_url 原因:

新版本的scrapy框架已经丢弃了这个函数的功能,但是并没有完全移除,虽然函数已经移除,但是还是在某些地方用到了这个,出现矛盾。

解决方法

自己在相对应的报错文件中重写一下这个方法
就是在

def make_requests_from_url(self,url): return scrapy.Request(url,dont_filter=True) 2.ValueError: unsupported format character : (0x3a) at index 9 问题:

我开起了redis的管道,将数据保存在了redis中,但是每次存储总是失败报错。

原因:

我在settings.py文件中重写了保存的方法,但是保存的写法不对导致我一直以为是源码的错误

# item存储键的设置 REDIS_ITEMS_KEY = '%(spider):items'

源码是

return self.spider % {"spider":spider.name}

太坑了,我为了这个错误差点重写了一个scrapy框架…

注意!如果你觉得你的主代码一点问题都没有,那就一定是配置文件的问题,大小写,配置环境字母不对等

三、scrapy正确的源代码 1.items.py文件 import scrapy class MyspiderItem(scrapy.Item): # define the fields for your item here like: lazyimg = scrapy.Field() title = scrapy.Field() resisted_data = scrapy.Field() mileage = scrapy.Field() city = scrapy.Field() price = scrapy.Field() sail_price = scrapy.Field() 2.settings.py文件 # Scrapy settings for myspider 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 = 'myspider' SPIDER_MODULES = ['myspider.spiders'] NEWSPIDER_MODULE = 'myspider.spiders' # Crawl responsibly by identifying yourself (and your website) on the user-agent # Obey robots.txt rules # LOG_LEVEL = "WARNING" # 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', #} # Enable or disable spider middlewares # See https://docs.scrapy.org/en/latest/topics/spider-middleware.html #SPIDER_MIDDLEWARES = { # 'myspider.middlewares.MyspiderSpiderMiddleware': 543, #} # Enable or disable downloader middlewares # See https://docs.scrapy.org/en/latest/topics/downloader-middleware.html #DOWNLOADER_MIDDLEWARES = { # 'myspider.middlewares.MyspiderDownloaderMiddleware': 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 # Crawl responsibly by identifying yourself (and your website) on the user-agent USER_AGENT = 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/95.0.4638.69 Safari/537.36' LOG_LEVEL = 'WARNING' LOG_FILE = './log.log' # Obey robots.txt rules ROBOTSTXT_OBEY = False # 指定管道 ,scrapy-redis组件帮我们写好 ITEM_PIPELINES = { "scrapy_redis.pipelines.RedisPipeline":400 } # 指定redis REDIS_HOST = '' # redis的服务器地址,我们现在用的是虚拟机上的回环地址 REDIS_PORT = # virtual Box转发redistribution的端口 # 去重容器类配置 作用:redis的set集合来存储请求的指纹数据,从而实现去重的持久化 DUPEFILTER_CLASS = 'scrapy_redis.dupefilter.RFPDupeFilter' # 使用scrapy-redis的调度器 SCHEDULER = 'scrapy_redis.scheduler.Scheduler' # 配置调度器是否需要持久化,爬虫结束的时候要不要清空redis中请求队列和指纹的set集合,要持久化设置为True SCHEDULER_PERSIST = True # 最大闲置时间,防止爬虫在分布式爬取的过程中关闭 # 这个仅在队列是SpiderQueue 或者 SpiderStack才会有作用, # 也可以阻塞一段时间,当你的爬虫刚开始时(因为刚开始时,队列是空的) SCHEDULER_IDLE_BEFORE_CLOSE = 10 # 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.taoche.py文件 import scrapy from scrapy.linkextractors import LinkExtractor from scrapy.spiders import CrawlSpider, Rule from scrapy_redis.spiders import RedisCrawlSpider from ..items import MyspiderItem import logging log = logging.getLogger(__name__) class TaocheSpider(RedisCrawlSpider): name = 'taoche' # allowed_domains = ['taoche.com'] # 不做域名限制 # start_urls = ['http://taoche.com/'] # 起始的url应该去redis(公共调度器) 里面获取 redis_key = 'taoche' # 回去redis(公共调度器)里面获取key为taoche的数据 taoche:[] # 老师,我给你找一下我改的源码在哪里,看看是那的错误吗 rules = ( # LinkExtractor 链接提取器,根据正则规则提取url地址 # callback 提取出来的url地址发送请求获取响应,会把响应对象给callback指定的函数进行处理 # follow 获取的响应页面是否再次经过rules进行提取url Rule(LinkExtractor(allow=r'/\?page=\d+?'), callback='parse_item', follow=True), ) def parse_item(self, response): print("开始解析数据") car_list = response.xpath('//div[@id="container_base"]/ul/li') for car in car_list: lazyimg = car.xpath('./div[1]/div/a/img/@src').extract_first() title = car.xpath('./div[2]/a/span/text()').extract_first() resisted_data = car.xpath('./div[2]/p/i[1]/text()').extract_first() mileage = car.xpath('./div[2]/p/i[2]/text()').extract_first() city = car.xpath('./div[2]/p/i[3]/text()').extract_first() city = city.replace('\n', '') city = city.strip() price = car.xpath('./div[2]/div[1]/i[1]/text()').extract_first() sail_price = car.xpath('./div[2]/div[1]/i[2]/text()').extract_first() item = MyspiderItem() item['lazyimg'] = lazyimg item['title'] = title item['resisted_data'] = resisted_data item['mileage'] = mileage item['city'] = city item['price'] = price item['sail_price'] = sail_price log.warning(item) # scrapy.Request(url=function,dont_filter=True) yield item 4.其余文件

中间件没有用到所以就没有写

管道用的是scrapy_redis里面的,自己也就不用写

总结

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