scrapy

一.手动发送get请求(处理分页操作)(递归解析)

在爬虫文件中

import scrapy
from choutidemo.items import ChoutidemoItem
item=ChoutidemoItem()
class ChoutiSpider(scrapy.Spider):
    name = 'chouti'
    start_urls = ['https://dig.chouti.com/r/scoff/hot/']
    page=2

    def parse(self, response):
        div_list=response.xpath('//div[@id="content-list"]/div')
        for div in div_list:
            actor=div.xpath('./div[2]/div[2]/a[4]/b/text() | ./div[3]/div[2]/a[4]/b/text()').extract_first()
            content=div.xpath('./div[2]/div[1]/a/text() | ./div[3]/div[1]/a/text()').extract_first()
            item["actor"]=actor
            item["content"]=content
            print(content)
            yield item
  ######################递归解析#处理分页操作#########################       
        if self.page<=5:
            url='https://dig.chouti.com/r/scoff/hot/%d' % self.page
            self.page=self.page+1
            yield scrapy.Request(url=url,callback=self.parse) #手动发送请求

在items.py中

import scrapy
class ChoutidemoItem(scrapy.Item):
    # define the fields for your item here like:
    actor = scrapy.Field()
    content = scrapy.Field()

在管道文件中

class ChoutidemoPipeline(object):
    f = None
    def open_spider(self, spider):
        print("开始爬虫!")
        self.f = open('./chouti1.txt', 'w', encoding='utf-8')

    def process_item(self, item, spider):
        self.f.write(item['actor'] + ':' + item['content'] + "\n")
        return item

    def close_spider(self, spider):
        print("结束爬虫!")
        self.f.close()

二.post请求(以百度翻译为例)

class ChoutidemoPipeline(object):
    f = None
    def open_spider(self, spider):
        print("开始爬虫!")
        self.f = open('./chouti1.txt', 'w', encoding='utf-8')

    def process_item(self, item, spider):
        self.f.write(item['actor'] + ':' + item['content'] + "\n")
        return item

    def close_spider(self, spider):
        print("结束爬虫!")
        self.f.close()

三.cookie的处理

使用scrapy模块,不需要自己处理cookie,scrapy模块已经帮我们处理了,但是一定要先登录才可以

使用方式:修改配置文件

COOKIES_ENABLED = True

四.请求传参

在爬虫文件中

import scrapy
from getmovie.items import GetmovieItem

class MovieSpider(scrapy.Spider):
    name = 'movie'
    start_urls = ['https://www.4567tv.tv/frim/index6.html']
    def parse_detail(self,response):
        #2.取出参数的格式
        item=response.meta["item"]
        content=response.xpath('//div[@class="stui-content__item clearfix"]/div[2]/p[5]/span[@class="detail-sketch"]/text()').extract_first()
        item["content"]=content
        yield item
    def parse(self, response):
        li_list=response.xpath('/html/body/div[1]/div/div/div/div[2]/ul/li')
        for li in li_list:
            item = GetmovieItem() #注:实例化一定要在此处,否则item["name"]总是最后一个值
            name=li.xpath('./div/div/h4/a/text()').extract_first()
            href='https://www.4567tv.tv'+li.xpath('./div/div/h4/a/@href').extract_first()
            item["name"]=name
            #1.传参的格式
            yield scrapy.Request(url=href,callback=self.parse_detail,meta={"item":item})

在items.py中

import scrapy
class GetmovieItem(scrapy.Item):
    name = scrapy.Field()
    content = scrapy.Field()
    pass

在管道文件中

class GetmoviePipeline(object):
    def open_spider(self, spider):
        print("开始爬虫!")
        self.f = open('./movie.txt', 'w', encoding='utf-8')

    def process_item(self, item, spider):
        self.f.write(item['name'] + ':' + item['content'] + "\n")
        return item

    def close_spider(self, spider):
        print("结束爬虫!")
        self.f.close()

五.日志等级

在配置文件中

LOG_LEVEL='ERROR' #显示错误
LOG_LEVEL='WARNING' #显示警告及错误

LOG_FILE='./log.txt' #日志信息存储到文本文件中

六.五大核心组件

引擎:

用来处理整个系统的数据处理,触发事物(框架核心)

调度器:

用来接收引擎发过来的请求,压入队列中,并在引擎再次请求的时候返回,可以想象成一个url的优先队列,由它来决定下一个要抓取的网址是什么,同时去除重复的网址

下载器:

用于下载网页内容,并将网页内容返回给下载器(此过程是建立在twisted 这个高效的模型上的)

爬虫:

用于从特定的网页中提取自己需要的信息,用户也可以提取出链接,用于抓取下一个页面

管道:

负责处理爬虫从网页中抽取出的实体,主要功能是持久化实体,验证实体的有效性,清除不需要的信息.

七.中间件

1.拦截请求(ip伪装,ua伪装)

from scrapy import signals
import random
class GetmovieDownloaderMiddleware(object):
    user_agent_list = [
        "Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.1 "
        "(KHTML, like Gecko) Chrome/22.0.1207.1 Safari/537.1",
        "Mozilla/5.0 (X11; CrOS i686 2268.111.0) AppleWebKit/536.11 "
        "(KHTML, like Gecko) Chrome/20.0.1132.57 Safari/536.11",
        "Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/536.6 "
        "(KHTML, like Gecko) Chrome/20.0.1092.0 Safari/536.6",
        "Mozilla/5.0 (Windows NT 6.2) AppleWebKit/536.6 "
        "(KHTML, like Gecko) Chrome/20.0.1090.0 Safari/536.6",
        "Mozilla/5.0 (Windows NT 6.2; WOW64) AppleWebKit/537.1 "
        "(KHTML, like Gecko) Chrome/19.77.34.5 Safari/537.1",
        "Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/536.5 "
        "(KHTML, like Gecko) Chrome/19.0.1084.9 Safari/536.5",
        "Mozilla/5.0 (Windows NT 6.0) AppleWebKit/536.5 "
        "(KHTML, like Gecko) Chrome/19.0.1084.36 Safari/536.5",
        "Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/536.3 "
        "(KHTML, like Gecko) Chrome/19.0.1063.0 Safari/536.3",
        "Mozilla/5.0 (Windows NT 5.1) AppleWebKit/536.3 "
        "(KHTML, like Gecko) Chrome/19.0.1063.0 Safari/536.3",
        "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_8_0) AppleWebKit/536.3 "
        "(KHTML, like Gecko) Chrome/19.0.1063.0 Safari/536.3",
        "Mozilla/5.0 (Windows NT 6.2) AppleWebKit/536.3 "
        "(KHTML, like Gecko) Chrome/19.0.1062.0 Safari/536.3",
        "Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/536.3 "
        "(KHTML, like Gecko) Chrome/19.0.1062.0 Safari/536.3",
        "Mozilla/5.0 (Windows NT 6.2) AppleWebKit/536.3 "
        "(KHTML, like Gecko) Chrome/19.0.1061.1 Safari/536.3",
        "Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/536.3 "
        "(KHTML, like Gecko) Chrome/19.0.1061.1 Safari/536.3",
        "Mozilla/5.0 (Windows NT 6.1) AppleWebKit/536.3 "
        "(KHTML, like Gecko) Chrome/19.0.1061.1 Safari/536.3",
        "Mozilla/5.0 (Windows NT 6.2) AppleWebKit/536.3 "
        "(KHTML, like Gecko) Chrome/19.0.1061.0 Safari/536.3",
        "Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/535.24 "
        "(KHTML, like Gecko) Chrome/19.0.1055.1 Safari/535.24",
        "Mozilla/5.0 (Windows NT 6.2; WOW64) AppleWebKit/535.24 "
        "(KHTML, like Gecko) Chrome/19.0.1055.1 Safari/535.24"
    ]
    PROXY_http = [
        '153.180.102.104:80',
        '195.208.131.189:56055',
    ]
    PROXY_https = [
        '120.83.49.90:9000',
        '95.189.112.214:35508',
    ]
    #拦截所有未发生异常的请求
    def process_request(self, request, spider):
        request.headers["User-Agent"]=random.choice(self.user_agent_list)
        return None
    #拦截所有的相应
    def process_response(self, request, response, spider):
        return response
    #拦截异常的请求
    def process_exception(self, request, exception, spider):
        if request.url.split(':')[0]=='http':
            request.meta["proxy"]=random.choice(self.PROXY_http)
        else:
            request.meta["proxy"] = random.choice(self.PROXY_https)

    def spider_opened(self, spider):
        spider.logger.info('Spider opened: %s' % spider.name)

配置文件中让中间件生效

DOWNLOADER_MIDDLEWARES = {
   'getmovie.middlewares.GetmovieDownloaderMiddleware': 543,
}

2.拦截相应(动态加载数据)

爬虫文件中

import scrapy
from selenium import webdriver

class DbanSpider(scrapy.Spider):
    name = 'dban'
    # allowed_domains = ['www.xxx.com']
    start_urls = ['https://movie.douban.com/typerank?type_name=喜剧&type=24&interval_id=100:90&action=']

    #先执行__init__函数,且只执行一次
    def __init__(self):
        #1.在init函数中创建浏览器对象,因为浏览器对象只需要创建一个
        self.bro=webdriver.Chrome(executable_path=r'C:\Users\Administrator\PycharmProjects\untitled3\pachong\day137\chromedriver.exe')
    def parse(self, response):
        #4.获取页面的所有数据并持久化处理
        all=response.xpath('/html').extract_first()
        with open('./douban.html','w',encoding='utf-8') as f:
            for line in all:
                f.write(line)
            f.close()
    #closed函数在parse函数循环结束和中间件执行完后执行一次
    def closed(self,spider):
        #5.关闭浏览器
        self.bro.quit()

中间件中

import time
from scrapy.http import HtmlResponse
class DoubanDownloaderMiddleware(object):

    def process_request(self, request, spider):
        return None

    def process_response(self, request, response, spider):
        #2.获取动态的数据
        bro=spider.bro
        bro.get(url=request.url)
        time.sleep(4)
        bro.execute_script('window.scrollTo(0,document.body.scrollHeight)')
        time.sleep(3)
        bro.execute_script('window.scrollTo(0,document.body.scrollHeight)')
        time.sleep(3)
        page_text=bro.page_source
        #3.封装一个HtmlResponse返回
        return HtmlResponse(url=spider.bro.current_url,body=page_text,encoding='utf-8')

    def process_exception(self, request, exception, spider):
        pass
    def spider_opened(self, spider):
        spider.logger.info('Spider opened: %s' % spider.name)

posted @ 2019-03-08 17:34 ★行者尚★ 阅读(260) 评论(0) 编辑收藏举报

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