Scrapy爬蟲之settings.py配置文件詳解

# -*- coding: utf-8 -*-  
  
# Scrapy settings for demo1 project  
#  
# For simplicity, this file contains only settings considered important or  
# commonly used. You can find more settings consulting the documentation:  
#  
#     http://doc.scrapy.org/en/latest/topics/settings.html  
#     http://scrapy.readthedocs.org/en/latest/topics/downloader-middleware.html  
#     http://scrapy.readthedocs.org/en/latest/topics/spider-middleware.html  
  
BOT_NAME = 'demo1'   #Scrapy項目的名字,這將用來構造默認 User-Agent,同時也用來log,當您使用 startproject 命令創建項目時其也被自動賦值。  
  
SPIDER_MODULES = ['demo1.spiders']   #Scrapy搜索spider的模塊列表 默認: [xxx.spiders]  
NEWSPIDER_MODULE = 'demo1.spiders'   #使用 genspider 命令創建新spider的模塊。默認: 'xxx.spiders'  
  
  
#爬取的默認User-Agent，除非被覆蓋  
#USER_AGENT = 'demo1 (+http://www.yourdomain.com)'  
  
#如果啓用,Scrapy將會採用 robots.txt策略  
ROBOTSTXT_OBEY = True  
  
#Scrapy downloader 併發請求(concurrent requests)的最大值,默認: 16  
#CONCURRENT_REQUESTS = 32  
  
#爲同一網站的請求配置延遲（默認值：0）  
# See http://scrapy.readthedocs.org/en/latest/topics/settings.html#download-delay  
# See also autothrottle settings and docs    
#DOWNLOAD_DELAY = 3   下載器在下載同一個網站下一個頁面前需要等待的時間,該選項可以用來限制爬取速度,減輕服務器壓力。同時也支持小數:0.25 以秒爲單位  
  
      
#下載延遲設置只有一個有效  
#CONCURRENT_REQUESTS_PER_DOMAIN = 16   對單個網站進行併發請求的最大值。  
#CONCURRENT_REQUESTS_PER_IP = 16       對單個IP進行併發請求的最大值。如果非0,則忽略 CONCURRENT_REQUESTS_PER_DOMAIN 設定,使用該設定。 也就是說,併發限制將針對IP,而不是網站。該設定也影響 DOWNLOAD_DELAY: 如果 CONCURRENT_REQUESTS_PER_IP 非0,下載延遲應用在IP而不是網站上。  
  
#禁用Cookie（默認情況下啓用）  
#COOKIES_ENABLED = False  
  
#禁用Telnet控制檯（默認啓用）  
#TELNETCONSOLE_ENABLED = False   
  
#覆蓋默認請求標頭：  
#DEFAULT_REQUEST_HEADERS = {  
#   'Accept': 'text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8',  
#   'Accept-Language': 'en',  
#}  
  
#啓用或禁用蜘蛛中間件  
# See http://scrapy.readthedocs.org/en/latest/topics/spider-middleware.html  
#SPIDER_MIDDLEWARES = {  
#    'demo1.middlewares.Demo1SpiderMiddleware': 543,  
#}  
  
#啓用或禁用下載器中間件  
# See http://scrapy.readthedocs.org/en/latest/topics/downloader-middleware.html  
#DOWNLOADER_MIDDLEWARES = {  
#    'demo1.middlewares.MyCustomDownloaderMiddleware': 543,  
#}  
  
#啓用或禁用擴展程序  
# See http://scrapy.readthedocs.org/en/latest/topics/extensions.html  
#EXTENSIONS = {  
#    'scrapy.extensions.telnet.TelnetConsole': None,  
#}  
  
#配置項目管道  
# See http://scrapy.readthedocs.org/en/latest/topics/item-pipeline.html  
#ITEM_PIPELINES = {  
#    'demo1.pipelines.Demo1Pipeline': 300,  
#}  
  
#啓用和配置AutoThrottle擴展（默認情況下禁用）  
# See http://doc.scrapy.org/en/latest/topics/autothrottle.html  
#AUTOTHROTTLE_ENABLED = True  
  
#初始下載延遲  
#AUTOTHROTTLE_START_DELAY = 5  
  
#在高延遲的情況下設置的最大下載延遲  
#AUTOTHROTTLE_MAX_DELAY = 60  
  
  
#Scrapy請求的平均數量應該並行發送每個遠程服務器  
#AUTOTHROTTLE_TARGET_CONCURRENCY = 1.0  
  
#啓用顯示所收到的每個響應的調節統計信息：  
#AUTOTHROTTLE_DEBUG = False  
  
#啓用和配置HTTP緩存（默認情況下禁用）  
# See http://scrapy.readthedocs.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'  

參考資料：

https://blog.csdn.net/u011781521/article/details/70188171

https://www.cnblogs.com/xueli/p/7250537.html