1. 程式人生 > >day26-爬蟲進階

day26-爬蟲進階

5.程式碼書寫請求-全棧資料爬取
例子4:爬取所有頁面choutiAll--手動請求傳送形式start_urls = ['https://dig.chouti.com/r/pic/hot/1']
解析抽屜圖片下所有的超鏈!
#設計了一個所有頁碼通用的url(pageNum表示的就是不同頁碼)
url = 'https://dig.chouti.com/r/pic/hot/%d'
重點是parse方法的呼叫yield scrapy.Request(url=url,callback=self.parse)
# -*- coding: utf-8 -*-
import scrapy
from choutiAllPro.items import ChoutiallproItem class ChoutiSpider(scrapy.Spider): name = 'chouti' #allowed_domains = ['www.ddd.com'] start_urls = ['https://dig.chouti.com/r/pic/hot/1'] #設計了一個所有頁碼通用的url(pageNum表示的就是不同頁碼) url = 'https://dig.chouti.com/r/pic/hot/%d' pageNum = 1 def parse(self, response): div_list
= response.xpath('//div[@class="content-list"]/div') for div in div_list: title = div.xpath('./div[3]/div[1]/a/text()').extract_first() item = ChoutiallproItem() item['title']=title yield item #進行其他頁碼對應url的請求操作 if
self.pageNum <= 120: #假設只有120個頁碼 self.pageNum += 1 url = format(self.url%self.pageNum) #print(url) #進行手動請求的傳送 yield scrapy.Request(url=url,callback=self.parse) #yield共傳送頁碼的次數,無yield只發一次!parse被遞迴的呼叫
chouti.py

//text獲取多個文字內容 /text獲取單個文字內容
scarpy框架會自動處理get請求的cookie

例子5:百度翻譯--發post請求--處理cookie--postPro
修改父類方法:
def start_requests(self):
for url in self.start_urls:
#該方法可以發起一個post請求
yield scrapy.FormRequest(url=url,callback=self.parse,formdata={'kw':'dog'})
# -*- coding: utf-8 -*-
import scrapy

#需求:對start_urls列表中的url發起post請求
class PostSpider(scrapy.Spider):
    name = 'post'
    #allowed_domains = ['www.xxx.com']
    start_urls = ['https://fanyi.baidu.com/sug']
    
    #Spider父類中的一個方法:可以將 start_urls列表中的url一次進行請求傳送
    def start_requests(self):
        for url in self.start_urls:
            # yield scrapy.Request(url=url, callback=self.parse) #預設發get請求
            #該方法可以發起一個post請求
            yield scrapy.FormRequest(url=url,callback=self.parse,formdata={'kw':'dog'}) #formdata處理攜帶的引數

    def parse(self, response):
        print(response.text) #結果為json串
post.py
      
例子6:登入操作(登入豆瓣電影),發post請求---loginPro
登入即可獲取cookie
# -*- coding: utf-8 -*-
import scrapy


class LoginSpider(scrapy.Spider):
    name = 'login'
    #allowed_domains = ['www.xxx.com']
    start_urls = ['https://accounts.douban.com/login']
    
    def start_requests(self):
        data = {
            'source':    'movie',
            'redir':    'https://movie.douban.com/',
            'form_email':    '15027900535',
            'form_password':    '[email protected]',
            'login':    '登入',
        }
        for url in self.start_urls:
            yield scrapy.FormRequest(url=url,callback=self.parse,formdata=data)
    
    def getPageText(self,response):
        page_text = response.text
        with open('./douban.html','w',encoding='utf-8') as fp:
            fp.write(page_text)
            print('over')
    
    def parse(self, response):
        #對當前使用者的個人主頁頁面進行獲取(有使用者資訊說明攜帶cookie,否則是登入介面)
        url = 'https://www.douban.com/people/185687620/'
        yield scrapy.Request(url=url,callback=self.getPageText)
login.py


6.scrapy核心元件--5大核心元件
總結流程描述:
引擎呼叫爬蟲檔案中的start_requests方法,將列表中url封裝成請求物件(start_urls、yield中的),會有一系列的請求物件,引擎將請求物件給排程器,排程器會進行去重,
請求物件放在排程器的佇列中,排程器將請求物件排程給下載器,下載器拿著請求物件到網際網路中下載,頁面資料下載完後給下載器,下載器給爬蟲檔案,
爬蟲檔案進行解析(呼叫parse方法),將解析後的資料封裝到item物件中,提交給管道,管道進行持久化儲存。
注意:排程器中佇列,排程器對請求物件有去重功能。
1.引擎:所有方法的呼叫
2.排程器:接收引擎傳送的請求,壓入到佇列中,去除重複網址
3.下載器:下載頁面內容,將下載好的頁面內容返回給蜘蛛(scrapy,就是爬蟲檔案)
4.爬蟲檔案(spiders):幹活的,將獲取的頁面資料進行解析操作
5.管道:進行持久化儲存
網際網路

下載中介軟體(介於排程器、引擎、爬蟲檔案和下載器的中間):可進行代理ip的更換
例子7:代理中介軟體的應用----dailiPro
daili.py的書寫;middlewares.py中DailiproDownloaderMiddleware下process_request方法
def process_request(self, request, spider):
#request引數表示的就是攔截到的請求物件
request.meta['proxy'] = "https://151.106.15.3:1080"
return None
在settings中DOWNLOADER_MIDDLEWARES開啟 55-57行
# -*- coding: utf-8 -*-
import scrapy


class DailiSpider(scrapy.Spider):
    name = 'daili'
    #allowed_domains = ['www.xxx.com']
    start_urls = ['https://www.baidu.com/s?wd=ip']

    def parse(self, response):
       page_text = response.text
       with open('daili.html','w',encoding='utf-8') as fp:
           fp.write(page_text)
daili.py
# -*- coding: utf-8 -*-
from scrapy import signals


class DailiproDownloaderMiddleware(object):

    @classmethod
    def from_crawler(cls, crawler):
        # This method is used by Scrapy to create your spiders.
        s = cls()
        crawler.signals.connect(s.spider_opened, signal=signals.spider_opened)
        return s

    def process_request(self, request, spider):
        # request引數表示的就是攔截到的請求物件
        request.meta['proxy'] = "https://151.106.15.3:1080"
        # request.meta={"https":"151.106.15.3:1080"} #不推薦
        return None

    def process_response(self, request, response, spider):
        return response

    def process_exception(self, request, exception, spider):
        pass

    def spider_opened(self, spider):
        spider.logger.info('Spider opened: %s' % spider.name)
middlewares.py
 1 # -*- coding: utf-8 -*-
 2 
 3 # Scrapy settings for dailiPro project
 4 #
 5 # For simplicity, this file contains only settings considered important or
 6 # commonly used. You can find more settings consulting the documentation:
 7 #
 8 #     https://doc.scrapy.org/en/latest/topics/settings.html
 9 #     https://doc.scrapy.org/en/latest/topics/downloader-middleware.html
10 #     https://doc.scrapy.org/en/latest/topics/spider-middleware.html
11 
12 BOT_NAME = 'dailiPro'
13 
14 SPIDER_MODULES = ['dailiPro.spiders']
15 NEWSPIDER_MODULE = 'dailiPro.spiders'
16 
17 
18 # Crawl responsibly by identifying yourself (and your website) on the user-agent
19 #USER_AGENT = 'dailiPro (+http://www.yourdomain.com)'
20 USER_AGENT = 'Mozilla/5.0 (Windows NT 6.1; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/70.0.3538.77 Safari/537.36'
21 # Obey robots.txt rules
22 ROBOTSTXT_OBEY = False
23 
24 # Configure maximum concurrent requests performed by Scrapy (default: 16)
25 #CONCURRENT_REQUESTS = 32
26 
27 # Configure a delay for requests for the same website (default: 0)
28 # See https://doc.scrapy.org/en/latest/topics/settings.html#download-delay
29 # See also autothrottle settings and docs
30 #DOWNLOAD_DELAY = 3
31 # The download delay setting will honor only one of:
32 #CONCURRENT_REQUESTS_PER_DOMAIN = 16
33 #CONCURRENT_REQUESTS_PER_IP = 16
34 
35 # Disable cookies (enabled by default)
36 #COOKIES_ENABLED = False
37 
38 # Disable Telnet Console (enabled by default)
39 #TELNETCONSOLE_ENABLED = False
40 
41 # Override the default request headers:
42 #DEFAULT_REQUEST_HEADERS = {
43 #   'Accept': 'text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8',
44 #   'Accept-Language': 'en',
45 #}
46 
47 # Enable or disable spider middlewares
48 # See https://doc.scrapy.org/en/latest/topics/spider-middleware.html
49 #SPIDER_MIDDLEWARES = {
50 #    'dailiPro.middlewares.DailiproSpiderMiddleware': 543,
51 #}
52 
53 # Enable or disable downloader middlewares
54 # See https://doc.scrapy.org/en/latest/topics/downloader-middleware.html
55 DOWNLOADER_MIDDLEWARES = {
56     'dailiPro.middlewares.DailiproDownloaderMiddleware': 543,
57 }
58 
59 # Enable or disable extensions
60 # See https://doc.scrapy.org/en/latest/topics/extensions.html
61 #EXTENSIONS = {
62 #    'scrapy.extensions.telnet.TelnetConsole': None,
63 #}
64 
65 # Configure item pipelines
66 # See https://doc.scrapy.org/en/latest/topics/item-pipeline.html
67 #ITEM_PIPELINES = {
68 #    'dailiPro.pipelines.DailiproPipeline': 300,
69 #}
70 
71 # Enable and configure the AutoThrottle extension (disabled by default)
72 # See https://doc.scrapy.org/en/latest/topics/autothrottle.html
73 #AUTOTHROTTLE_ENABLED = True
74 # The initial download delay
75 #AUTOTHROTTLE_START_DELAY = 5
76 # The maximum download delay to be set in case of high latencies
77 #AUTOTHROTTLE_MAX_DELAY = 60
78 # The average number of requests Scrapy should be sending in parallel to
79 # each remote server
80 #AUTOTHROTTLE_TARGET_CONCURRENCY = 1.0
81 # Enable showing throttling stats for every response received:
82 #AUTOTHROTTLE_DEBUG = False
83 
84 # Enable and configure HTTP caching (disabled by default)
85 # See https://doc.scrapy.org/en/latest/topics/downloader-middleware.html#httpcache-middleware-settings
86 #HTTPCACHE_ENABLED = True
87 #HTTPCACHE_EXPIRATION_SECS = 0
88 #HTTPCACHE_DIR = 'httpcache'
89 #HTTPCACHE_IGNORE_HTTP_CODES = []
90 #HTTPCACHE_STORAGE = 'scrapy.extensions.httpcache.FilesystemCacheStorage'
91 
92 #DEBUG  INFO  ERROR  WARNING
93 #LOG_LEVEL = 'ERROR'
94 
95 LOG_FILE = 'log.txt'
settings.py


7.日誌資訊的設定
日誌登記 #DEBUG INFO ERROR WARNING
在settings中寫 #LOG_LEVEL = 'ERROR' 只輸出error型別的日誌
LOG_FILE = 'log.txt'日誌輸出到檔案,上看6.上面settings.py中配置


8.請求傳參 :爬取的資料不在同一個頁面中
正則未生效!???
例子8:請求傳參---爬取電影詳情的資料---moviePro
將不同頁面的值放到同一個item裡(名稱和作者)
手動發請求--yield
請求傳參:通過Request方法的meta引數將某一個具體的資料值傳遞給request方法中指定的callback方法,callback中方法通過response去取,
item = response.meta['item'] 一個取name,二級子頁面中取author
yield scrapy.Request(url=url,callback=self.getSencodPageText,meta={'item':item}

def getSencodPageText(self,response):
#2.接收Request方法傳遞過來的item物件
item = response.meta['item']
# -*- coding: utf-8 -*-
import scrapy
from moviePro.items import MovieproItem

class MovieSpider(scrapy.Spider):
    name = 'movie'
    #allowed_domains = ['www.xxx.com']
    start_urls = ['https://www.dy2018.com/html/gndy/dyzz/']
    #該方法可以將電影詳情頁中的資料進行解析
    def getSencodPageText(self,response):
        #2.接收Request方法傳遞過來的item物件
        item = response.meta['item']
        actor = response.xpath('//*[@id="Zoom"]/p[16]/text()').extract_first()
        item['actor'] = actor
        
        yield item
        
    def parse(self, response):
        print(response.text)
        table_list = response.xpath('//div[@class="co_content8"]/ul/table')
        for table in table_list:
            url = "https://www.dy2018.com"+table.xpath('./tbody/tr[2]/td[2]/b/a/@href').extract_first() #需要加https字首
            name = table.xpath('./tbody/tr[2]/td[2]/b/a/text()').extract_first()
            print(url)
            item = MovieproItem() #例項化item型別物件
            item['name']=name
            
            #1.讓Request方法將item物件傳遞給getSencodPageText方法,加入meta
            yield scrapy.Request(url=url,callback=self.getSencodPageText,meta={'item':item}) #手動發請求
            
movie.py


9.SrawlSpider的使用--連結提取器&規則解析器
SrawlSpider可以進行全棧資料的爬取! --重點!
例子9:SrawlSpider的使用--爬取糗百圖片全棧資料--crawlPro
注意:專案建立 scrapy genspider -t crawl qiubai www.xxx.com
取第一頁的標籤?--注意allow取得是符合正則的連結 link1 = LinkExtractor(allow=r'/pic/$')
# -*- coding: utf-8 -*-
import scrapy
from scrapy.linkextractors import LinkExtractor
from scrapy.spiders import CrawlSpider, Rule


class QiubaiSpider(CrawlSpider):
    name = 'qiubai'
    #allowed_domains = ['www.xxx.com']
    start_urls = ['https://www.qiushibaike.com/pic/']
    #連線提取器(提取頁碼連線):從起始url表示的頁面原始碼中進行指定連線的提取
    #allow引數:正則表示式。可以將起始url頁面原始碼資料中符合該正則的連線進行全部的提取
    link = LinkExtractor(allow=r'/pic/page/\d+\?s=\d+')
    #href="/pic/page/5?s=5144132"
    
    link1 = LinkExtractor(allow=r'/pic/$') #正則表示式提取到的是所有連線的內容
    #href="/pic/"
    rules = (
        #規則解析器:將連線提取器提取到的連線對應的頁面資料進行指定(callback)負責解析
        #follow = True:將連線提取器繼續作用到連線提取器提取出的連線所對應的頁面中(會繼續作用於link中);為False時,只會作用到start_urls,出現幾個結果。
        Rule(link, callback='parse_item', follow=True),
        Rule(link1, callback='parse_item', follow=True),
    )

    def parse_item(self, response):
        print(response)
        
    
qiubai.py


10.分散式爬取--多臺機器同時爬取同一頁面資料--重點!
在pycharm中下載redis

例子10:分散式爬取--爬取抽屜42區--redisPro
#爬取抽屜42區所有圖片所對應的url連線
提交到redis中的管道
settings.py中ITEM_PIPELINES = {
'scrapy_redis.pipelines.RedisPipeline': 400
}
 1 # -*- coding: utf-8 -*-
 2 import scrapy
 3 from scrapy.linkextractors import LinkExtractor
 4 from scrapy.spiders import CrawlSpider, Rule
 5 from scrapy_redis.spiders import RedisCrawlSpider
 6 from redisPro.items import RedisproItem
 7 #0.將RedisCrawlSpider類進行匯入
 8 #1.將爬蟲類的父類修改成RedisCrawlSpider
 9 #2.將start_urls修改成redis_key屬性
10 #3.編寫具體的解析程式碼
11 # 4.將item提交到scrapy-redis元件中被封裝好的管道里(settings.py中ITEM_PIPELINES = {
12 #     'scrapy_redis.pipelines.RedisPipeline': 400
13 # })
14 #5.將爬蟲檔案中產生的url對應的請求物件全部都提交到scrapy-redis封裝好的排程器中(settings.py中配置95-10015 #6.在配置檔案中指明將爬取到的資料值儲存到哪一個redis資料庫中(settings.py中105-10816 #7.對redis資料庫的配置檔案(redis.windows.conf)進行修改:protected-mode no   #bind 127.0.0.1
17 #8.執行爬蟲檔案:scrapy runspider xxx.py
18 #9.向排程器中扔一個起始的url
19 class ChoutiSpider(RedisCrawlSpider):
20     name = 'chouti'
21     #allowed_domains = ['www.xxx.com']
22     #start_urls = ['http://www.xxx.com/']
23     #排程器佇列的名稱:將起始的url扔到該名稱表示的排程器佇列中
24     redis_key = "chouti"
25     
26     rules = (
27         Rule(LinkExtractor(allow=r'/r/news/hot/\d+'), callback='parse_item', follow=True),
28     )
29 
30     def parse_item(self, response):
31         
32         imgUrl_list =  response.xpath('//div[@class="news-pic"]/img/@src').extract()
33         for url in imgUrl_list:
34             item = RedisproItem()
35             item['url'] = url
36             
37             yield item
chouti.py
  1 # -*- coding: utf-8 -*-
  2 
  3 # Scrapy settings for redisPro project
  4 #
  5 # For simplicity, this file contains only settings considered important or
  6 # commonly used. You can find more settings consulting the documentation:
  7 #
  8 #     https://doc.scrapy.org/en/latest/topics/settings.html
  9 #     https://doc.scrapy.org/en/latest/topics/downloader-middleware.html
 10 #     https://doc.scrapy.org/en/latest/topics/spider-middleware.html
 11 
 12 BOT_NAME = 'redisPro'
 13 
 14 SPIDER_MODULES = ['redisPro.spiders']
 15 NEWSPIDER_MODULE = 'redisPro.spiders'
 16 
 17 
 18 # Crawl responsibly by identifying yourself (and your website) on the user-agent
 19 #USER_AGENT = 'redisPro (+http://www.yourdomain.com)'
 20 USER_AGENT = 'Mozilla/5.0 (Windows NT 6.1; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/70.0.3538.77 Safari/537.36'
 21 # Obey robots.txt rules
 22 ROBOTSTXT_OBEY = False
 23 
 24 # Configure maximum concurrent requests performed by Scrapy (default: 16)
 25 #CONCURRENT_REQUESTS = 32
 26 
 27 # Configure a delay for requests for the same website (default: 0)
 28 # See https://doc.scrapy.org/en/latest/topics/settings.html#download-delay
 29 # See also autothrottle settings and docs
 30 #DOWNLOAD_DELAY = 3
 31 # The download delay setting will honor only one of:
 32 #CONCURRENT_REQUESTS_PER_DOMAIN = 16
 33 #CONCURRENT_REQUESTS_PER_IP = 16
 34 
 35 # Disable cookies (enabled by default)
 36 #COOKIES_ENABLED = False
 37 
 38 # Disable Telnet Console (enabled by default)
 39 #TELNETCONSOLE_ENABLED = False
 40 
 41 # Override the default request headers:
 42 #DEFAULT_REQUEST_HEADERS = {
 43 #   'Accept': 'text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8',
 44 #   'Accept-Language': 'en',
 45 #}
 46 
 47 # Enable or disable spider middlewares
 48 # See https://doc.scrapy.org/en/latest/topics/spider-middleware.html
 49 #SPIDER_MIDDLEWARES = {
 50 #    'redisPro.middlewares.RedisproSpiderMiddleware': 543,
 51 #}
 52 
 53 # Enable or disable downloader middlewares
 54 # See https://doc.scrapy.org/en/latest/topics/downloader-middleware.html
 55 #DOWNLOADER_MIDDLEWARES = {
 56 #    'redisPro.middlewares.RedisproDownloaderMiddleware': 543,
 57 #}
 58 
 59 # Enable or disable extensions
 60 # See https://doc.scrapy.org/en/latest/topics/extensions.html
 61 #EXTENSIONS = {
 62 #    'scrapy.extensions.telnet.TelnetConsole': None,
 63 #}
 64 
 65 # Configure item pipelines
 66 # See https://doc.scrapy.org/en/latest/topics/item-pipeline.html
 67 ITEM_PIPELINES = {
 68     'scrapy_redis.pipelines.RedisPipeline': 400
 69 
 70 #    'redisPro.pipelines.RedisproPipeline': 300,
 71 
 72 }
 73 
 74 # Enable and configure the AutoThrottle extension (disabled by default)
 75 # See https://doc.scrapy.org/en/latest/topics/autothrottle.html
 76 #AUTOTHROTTLE_ENABLED = True
 77 # The initial download delay
 78 #AUTOTHROTTLE_START_DELAY = 5
 79 # The maximum download delay to be set in case of high latencies
 80 #AUTOTHROTTLE_MAX_DELAY = 60
 81 # The average number of requests Scrapy should be sending in parallel to
 82 # each remote server
 83 #AUTOTHROTTLE_TARGET_CONCURRENCY = 1.0
 84 # Enable showing throttling stats for every response received:
 85 #AUTOTHROTTLE_DEBUG = False
 86 
 87 # Enable and configure HTTP caching (disabled by default)
 88 # See https://doc.scrapy.org/en/latest/topics/downloader-middleware.html#httpcache-middleware-settings
 89 #HTTPCACHE_ENABLED = True
 90 #HTTPCACHE_EXPIRATION_SECS = 0
 91 #HTTPCACHE_DIR = 'httpcache'
 92 #HTTPCACHE_IGNORE_HTTP_CODES = []
 93 #HTTPCACHE_STORAGE = 'scrapy.extensions.httpcache.FilesystemCacheStorage'
 94 
 95 # 使用scrapy-redis元件的去重佇列
 96 DUPEFILTER_CLASS = "scrapy_redis.dupefilter.RFPDupeFilter"
 97 # 使用scrapy-redis元件自己的排程器
 98 SCHEDULER = "scrapy_redis.scheduler.Scheduler"
 99 # 是否允許暫停
100 SCHEDULER_PERSIST = True
101 
102 
103 
104 
105 REDIS_HOST = '192.168.12.65'
106 REDIS_PORT = 6379
107 #REDIS_ENCODING = ‘utf-8108 #REDIS_PARAMS = {‘password’:’123456’}
settings.py

 


redis配置檔案中註釋56行 75儲存模式改為no
執行:
1.啟動redis伺服器:進入到redis目錄,在cmd中輸入redis-server ./redis.windows.conf
2.啟動redis 資料庫客戶端:redis cli

3.執行配置檔案:cmd進入到F:\Python自動化21期\3.Django&專案\day26 爬蟲1104\課上程式碼及筆記\scrapy專案\redisPro\redisPro\spiders下的chouti.py目錄,
scrapy runspider chouti.py 會停在監聽的位置

4.在redis中:redis-cli
lpush chouti https://dig.chouti.com/r/news/hot/1 執行之後專案cmd中會進行資料爬取操作

5.在redis中檢視爬取的資料
keys * -------存在chouti:items
lrange chouti:items 0 -1

刪除資料:redis cli
flushall即可

  
小結18:40-50 總結的答案:
1.2種爬蟲模組,requests、urllib
2.robots協議作用:防君子不妨小人,常用的一種反扒手段
3.使用雲打碼或者人工識別--注:驗證碼也是入口網站的一種反扒手段
4.3種解析方式:xpath、BeautifulSoup、正則
5.selenium--執行js程式碼/PhantomJs、谷歌無頭瀏覽器
6.重要!資料加密(下載密文),動態資料爬取(梨視訊)
token--登入時rkey對應的值
7.5個,爬蟲檔案、引擎、排程器、下載器、管道
8.sqiders/CrawlSpider/RedisCrawlSpider
9.總結的10步---可以自己嘗試--分散式樣本儲存
10.未講到




想要的內容括起來