【Python网络蜘蛛 · 14】：Scrapy中settings.py文件中的相关配置说明

settings.py文件中的相关配置说明

---

# Scrapy settings for Douban 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 = 'Douban'

SPIDER_MODULES = ['Douban.spiders']
NEWSPIDER_MODULE = 'Douban.spiders'


# Crawl responsibly by identifying yourself (and your website) on the user-agent
#USER_AGENT = 'Douban (+http://www.yourdomain.com)'
USER_AGENT = 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/104.0.0.0 Safari/537.36'
# Obey robots.txt rules
ROBOTSTXT_OBEY = True

# 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',
   'Cookie':'……'
}

# Enable or disable spider middlewares
# See https://docs.scrapy.org/en/latest/topics/spider-middleware.html
#SPIDER_MIDDLEWARES = {
#    'Douban.middlewares.DoubanSpiderMiddleware': 543,
#}

# Enable or disable downloader middlewares
# See https://docs.scrapy.org/en/latest/topics/downloader-middleware.html
DOWNLOADER_MIDDLEWARES = {
   'Douban.middlewares.DoubanDownloaderMiddleware': 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 = {
   # 'Douban.pipelines.DoubanPipeline': 300,
   'Douban.pipelines.Douban250Pipeline': 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'

USER_AGENT配置

根据网页检查，找到user_agent进行配置即可

USER_AGENT = 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/104.0.0.0 Safari/537.36'

ROBOTSTXT_OBEY 协议

默认为True，就是要遵守robots.txt 的规则

robots.txt ，通俗来说， robots.txt 是遵循 Robot协议
的一个文件，它保存在网站的服务器中，它的作用是，告诉搜索引擎爬虫，本网站哪些目录下的网页 不希望
你进行爬取收录。在Scrapy启动后，会在第一时间访问网站的 robots.txt 文件，然后决定该网站的爬取范围。

当然，我们并不是在做搜索引擎，而且在某些情况下我们想要获取的内容恰恰是被 robots.txt
所禁止访问的。所以，某些时候，我们就要将此配置项设置为 False ，拒绝遵守 Robot协议 ！

DOWNLOAD_DELAY

DOWNLOAD_DELAY 通俗理解为下载延迟，单位为秒

DOWNLOAD_DELAY = 3

DOWNLOADER_MIDDLEWARES 下载中间件

一般选择打开

DOWNLOADER_MIDDLEWARES = {
   'Douban.middlewares.DoubanDownloaderMiddleware': 543,
}

ITEM_PIPELINES 管道

配置项中键为使用的管道类，管道类使用.进行分割，第一个为项目目录，第二个为文件，第三个为定义的管道类。 配置项中值为管道的使用顺序，设置的数值约小越优先执行，该值一般设置为1000以内。

ITEM_PIPELINES = {
   # 'Douban.pipelines.DoubanPipeline': 300,
   'Douban.pipelines.Douban250Pipeline': 300,
}

COOKIES_ENABLED 配置cookie

在settings.py文件中默认注释

# COOKIES_ENABLED = False

• 当COOKIES_ENABLED = False，scrapy默认使用settings中的cookie，并在settings中DEFAULT_REQUEST_HEADERS 添加cookie

DEFAULT_REQUEST_HEADERS = {
   'Accept': 'text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8',
   'Accept-Language': 'en',
   'Cookie':'……'
}

• 当COOKIES_ENABLED = True，scrapy会把settings中的cookie关掉，使用自定义的cookie