爬虫Scrapy框架学习（二）

深入了解setting.py文件（附整个setting文件内容-已做批注）

# -*- coding: utf-8 -*-

# Scrapy settings for yangguang project
#
# For simplicity, this file contains only settings considered important or
# commonly used. You can find more settings consulting the documentation:
#
#     https://doc.scrapy.org/en/latest/topics/settings.html
#     https://doc.scrapy.org/en/latest/topics/downloader-middleware.html
#     https://doc.scrapy.org/en/latest/topics/spider-middleware.html

BOT_NAME = 'yangguang'

SPIDER_MODULES = ['yangguang.spiders']                            #爬虫位置
NEWSPIDER_MODULE = 'yangguang.spiders'                            #新建爬虫的放置位置

LOG_LEVEL = "WARNING"


# Crawl responsibly by identifying yourself (and your website) on the user-agent
USER_AGENT = 'Mozilla/5.0 (Windows NT 6.3; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/69.0.3497.100 Safari/537.36'

# Obey robots.txt rules
ROBOTSTXT_OBEY = True                                             #默认情况下是否遵守robot协议

# Configure maximum concurrent requests performed by Scrapy (default: 16)
#CONCURRENT_REQUESTS = 32                                         #设置最大并发请求（默认是16个）

# Configure a delay for requests for the same website (default: 0)
# See https://doc.scrapy.org/en/latest/topics/settings.html#download-delay
# See also autothrottle settings and docs
#DOWNLOAD_DELAY = 3                                               #下载延迟（使整个爬虫慢一些，防止反爬虫）
# The download delay setting will honor only one of:
#CONCURRENT_REQUESTS_PER_DOMAIN = 16                              #每一个域名的最大并发请求数（几乎不会用到）
#CONCURRENT_REQUESTS_PER_IP = 16                                  #每一个id的最大并发请求数（几乎不会用到）

# Disable cookies (enabled by default)
#COOKIES_ENABLED = False                                           #cookie是否开启（默认是开启的）

# Disable Telnet Console (enabled by default)
#TELNETCONSOLE_ENABLED = False

# Override the default request headers:                            #默认请求头
#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://doc.scrapy.org/en/latest/topics/spider-middleware.html
#SPIDER_MIDDLEWARES = {                                             #爬虫中间件
#    'yangguang.middlewares.YangguangSpiderMiddleware': 543,
#}

# Enable or disable downloader middlewares
# See https://doc.scrapy.org/en/latest/topics/downloader-middleware.html
#DOWNLOADER_MIDDLEWARES = {                                          #下载中间件
#    'yangguang.middlewares.YangguangDownloaderMiddleware': 543,
#}

# Enable or disable extensions
# See https://doc.scrapy.org/en/latest/topics/extensions.html
#EXTENSIONS = {
#    'scrapy.extensions.telnet.TelnetConsole': None,
#}

# Configure item pipelines
# See https://doc.scrapy.org/en/latest/topics/item-pipeline.html
ITEM_PIPELINES = {
   'yangguang.pipelines.YangguangPipeline': 300,
}

# Enable and configure the AutoThrottle extension (disabled by default)  #自动限速（一般不需要）
# See https://doc.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)                    #http缓存
# See https://doc.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'