1、知识点
""""
pipelines使用：
1、在spiders里面使用yield生成器
list_li = response.xpath("//div[@class='swiper-wrapper']//li")
#print(list_li)
for li in list_li:
#print(li.extract_first())
item = { }
item["name"] = li.xpath(".//h3/text()").extract_first()
item["content"] = li.xpath(".//p[@class='teacherBrief']/text()").extract_first()
#item["content"] = li.xpath(".//p[@class='teacherIntroduction']/text()").extract_first()
#print(item)
yield item #将数据传递道pipelines 2、在pipelines中打印item
class MyspiderPipeline(object):
"""
#第一个管道，这个process_item方法名是不能改
"""
def process_item(self, item, spider):
item["hello"] = "world"
print(item)
return item class MyspiderPipeline1(object):
"""
#第二个管道
"""
def process_item(self, item, spider):
print(item)
return item 3、在settings文件添加pipelines的支持
ITEM_PIPELINES = {
#执行顺序为从小到大，即先执行300，然后在301
'myspider.pipelines.MyspiderPipeline': 300,
'myspider.pipelines.MyspiderPipeline1': 301,
}
"""
2、spider.py文件中通过
yield item #将数据传递道pipelines.py中的item
JulyeduSpider.py文件代码
# -*- coding: utf-8 -*-
import scrapy
import logging logger = logging.getLogger(__name__)
class JulyeduSpider(scrapy.Spider):
name = 'julyedu'
allowed_domains = ['julyedu.com']
start_urls = ['http://julyedu.com/']
#这个parse方法名不能改
def parse(self, response):
"""
爬虫七月在线的导师名单
:param response:
:return:
"""
list_li = response.xpath("//div[@class='swiper-wrapper']//li")
#print(list_li)
item = {}
for li in list_li:
item["name"] = li.xpath(".//h3/text()").extract_first()
item["content"] = li.xpath(".//p[@class='teacherBrief']/text()").extract_first()
#item["content"] = li.xpath(".//p[@class='teacherIntroduction']/text()").extract_first()
#print(item)
#将数据传递道pipelines，yield只接受Request,BaseItem，dict,None四种类型
logger.warning(item) #打印日志
yield item
2、修改pipelines.py文件，对其中的item可以操作
# -*- coding: utf-8 -*- # Define your item pipelines here
#
# Don't forget to add your pipeline to the ITEM_PIPELINES setting
# See: https://doc.scrapy.org/en/latest/topics/item-pipeline.html class MyspiderPipeline(object):
"""
第一个管道，这个process_item方法名是不能改
"""
def process_item(self, item, spider):
"""
针对不同的爬虫的数据处理
:param item:spider 传过来的值
:param spider: 传递过来spider的类
:return:
"""
if spider.name == "julyedu":
#print(item)
return item
else:
return item class MyspiderPipeline1(object):
"""
第二个管道
"""
def process_item(self, item, spider):
#print(item)
return item
3、对settings.py文件添加pipelines配置
# -*- coding: utf-8 -*- # 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://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 = 'myspider' SPIDER_MODULES = ['myspider.spiders']
NEWSPIDER_MODULE = 'myspider.spiders' LOG_LEVEL = 'WARNING' #增加log日志
LOG_FILE='./log.log' #将log日志保存到文件中
# Crawl responsibly by identifying yourself (and your website) on the user-agent
#USER_AGENT = 'myspider (+http://www.yourdomain.com)' # 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://doc.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://doc.scrapy.org/en/latest/topics/spider-middleware.html
#SPIDER_MIDDLEWARES = {
# 'myspider.middlewares.MyspiderSpiderMiddleware': 543,
#} # Enable or disable downloader middlewares
# See https://doc.scrapy.org/en/latest/topics/downloader-middleware.html
#DOWNLOADER_MIDDLEWARES = {
# 'myspider.middlewares.MyspiderDownloaderMiddleware': 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 = {
#执行顺序为从小到大，即先执行300，然后在301
'myspider.pipelines.MyspiderPipeline': 300,
'myspider.pipelines.MyspiderPipeline1': 301,
} # Enable and configure the AutoThrottle extension (disabled by default)
# 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)
# 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'