目錄

前言

環境部署

實現過程

創建項目

定義Item實體

關鍵詞提取工具

爬蟲構造

中間件代碼構造

制作自定義pipeline

settings配置

執行主程序

執行結果

總結

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前言

接著我的上一篇：如何爬取CSDN全站綜合熱榜標題，順便統計關鍵詞詞頻 ｜ 爬蟲案例_阿良的博客-CSDN博客

我換成Scrapy架構也實現了一遍。獲取頁面源碼底層原理是一樣的，Scrapy架構更系統一些。下面我會把需要注意的問題，也說明一下。

提供一下GitHub倉庫地址：github本項目地址

環境部署

scrapy安裝

pip install scrapy -i https://pypi.douban.com/simple

selenium安裝

pip install selenium -i https://pypi.douban.com/simple

jieba安裝

pip install jieba -i https://pypi.douban.com/simple

IDE：PyCharm

google chrome driver下載對應版本：google chrome driver下載地址

檢查瀏覽器版本，下載對應版本。

實現過程

下面開始搞起。

創建項目

使用scrapy命令創建我們的項目。

scrapy startproject csdn_hot_words

?項目結構，如同官方給出的結構。

定義Item實體

按照之前的邏輯，主要屬性為標題關鍵詞對應出現次數的字典。代碼如下：

# Define here the models for your scraped items # # See documentation in: # https://docs.scrapy.org/en/latest/topics/items.htmlimport scrapyclass CsdnHotWordsItem(scrapy.Item):# define the fields for your item here like:# name = scrapy.Field()words = scrapy.Field()

關鍵詞提取工具

使用jieba分詞獲取工具。

#!/usr/bin/env python # -*- coding: utf-8 -*- # @Time : 2021/11/5 23:47 # @Author : 至尊寶 # @Site : # @File : analyse_sentence.pyimport jieba.analysedef get_key_word(sentence):result_dic = {}words_lis = jieba.analyse.extract_tags(sentence, topK=3, withWeight=True, allowPOS=())for word, flag in words_lis:if word in result_dic:result_dic[word] += 1else:result_dic[word] = 1return result_dic

爬蟲構造

這里需要給爬蟲初始化一個瀏覽器參數，用來實現頁面的動態加載。

#!/usr/bin/env python # -*- coding: utf-8 -*- # @Time : 2021/11/5 23:47 # @Author : 至尊寶 # @Site : # @File : csdn.pyimport scrapy from selenium import webdriver from selenium.webdriver.chrome.options import Optionsfrom csdn_hot_words.items import CsdnHotWordsItem from csdn_hot_words.tools.analyse_sentence import get_key_wordclass CsdnSpider(scrapy.Spider):name = 'csdn'# allowed_domains = ['blog.csdn.net']start_urls = ['https://blog.csdn.net/rank/list']def __init__(self):chrome_options = Options()chrome_options.add_argument('--headless') # 使用無頭谷歌瀏覽器模式chrome_options.add_argument('--disable-gpu')chrome_options.add_argument('--no-sandbox')self.browser = webdriver.Chrome(chrome_options=chrome_options,executable_path="E:\\chromedriver_win32\\chromedriver.exe")self.browser.set_page_load_timeout(30)def parse(self, response, **kwargs):titles = response.xpath("//div[@class='hosetitem-title']/a/text()")for x in titles:item = CsdnHotWordsItem()item['words'] = get_key_word(x.get())yield item

代碼說明?

1、這里使用的是chrome的無頭模式，就不需要有個瀏覽器打開再訪問，都是后臺執行的。

2、需要添加chromedriver的執行文件地址。

3、在parse的部分，可以參考之前我文章的xpath，獲取到標題并且調用關鍵詞提取，構造item對象。

中間件代碼構造

添加js代碼執行內容。中間件完整代碼：

# Define here the models for your spider middleware # # See documentation in: # https://docs.scrapy.org/en/latest/topics/spider-middleware.htmlfrom scrapy import signals from scrapy.http import HtmlResponse from selenium.common.exceptions import TimeoutException import timefrom selenium.webdriver.chrome.options import Options# useful for handling different item types with a single interface from itemadapter import is_item, ItemAdapterclass CsdnHotWordsSpiderMiddleware:# Not all methods need to be defined. If a method is not defined,# scrapy acts as if the spider middleware does not modify the# passed objects.@classmethoddef 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 sdef process_spider_input(self, response, spider):# Called for each response that goes through the spider# middleware and into the spider.# Should return None or raise an exception.return Nonedef process_spider_output(self, response, result, spider):# Called with the results returned from the Spider, after# it has processed the response.# Must return an iterable of Request, or item objects.for i in result:yield idef process_spider_exception(self, response, exception, spider):# Called when a spider or process_spider_input() method# (from other spider middleware) raises an exception.# Should return either None or an iterable of Request or item objects.passdef process_start_requests(self, start_requests, spider):# Called with the start requests of the spider, and works# similarly to the process_spider_output() method, except# that it doesn’t have a response associated.# Must return only requests (not items).for r in start_requests:yield rdef spider_opened(self, spider):spider.logger.info('Spider opened: %s' % spider.name)class CsdnHotWordsDownloaderMiddleware:# Not all methods need to be defined. If a method is not defined,# scrapy acts as if the downloader middleware does not modify the# passed objects.@classmethoddef 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 sdef process_request(self, request, spider):js = '''let height = 0let interval = setInterval(() => {window.scrollTo({top: height,behavior: "smooth"});height += 500}, 500);setTimeout(() => {clearInterval(interval)}, 20000);'''try:spider.browser.get(request.url)spider.browser.execute_script(js)time.sleep(20)return HtmlResponse(url=spider.browser.current_url, body=spider.browser.page_source,encoding="utf-8", request=request)except TimeoutException as e:print('超時異常:{}'.format(e))spider.browser.execute_script('window.stop()')finally:spider.browser.close()def process_response(self, request, response, spider):# Called with the response returned from the downloader.# Must either;# - return a Response object# - return a Request object# - or raise IgnoreRequestreturn responsedef process_exception(self, request, exception, spider):# Called when a download handler or a process_request()# (from other downloader middleware) raises an exception.# Must either:# - return None: continue processing this exception# - return a Response object: stops process_exception() chain# - return a Request object: stops process_exception() chainpassdef spider_opened(self, spider):spider.logger.info('Spider opened: %s' % spider.name)

制作自定義pipeline

定義按照詞頻統計最終結果輸出到文件。代碼如下：

# Define your item pipelines here # # Don't forget to add your pipeline to the ITEM_PIPELINES setting # See: https://docs.scrapy.org/en/latest/topics/item-pipeline.html# useful for handling different item types with a single interface from itemadapter import ItemAdapterclass CsdnHotWordsPipeline:def __init__(self):self.file = open('result.txt', 'w', encoding='utf-8')self.all_words = []def process_item(self, item, spider):self.all_words.append(item)return itemdef close_spider(self, spider):key_word_dic = {}for y in self.all_words:print(y)for k, v in y['words'].items():if k.lower() in key_word_dic:key_word_dic[k.lower()] += velse:key_word_dic[k.lower()] = vword_count_sort = sorted(key_word_dic.items(),key=lambda x: x[1], reverse=True)for word in word_count_sort:self.file.write('{},{}\n'.format(word[0], word[1]))self.file.close()

settings配置

配置上要做一些調整。如下調整：

# Scrapy settings for csdn_hot_words project # # For simplicity, this file contains only settings considered important or # commonly used. You can find more settings consulting the documentation: # # https://docs.scrapy.org/en/latest/topics/settings.html # https://docs.scrapy.org/en/latest/topics/downloader-middleware.html # https://docs.scrapy.org/en/latest/topics/spider-middleware.htmlBOT_NAME = 'csdn_hot_words'SPIDER_MODULES = ['csdn_hot_words.spiders'] NEWSPIDER_MODULE = 'csdn_hot_words.spiders'# Crawl responsibly by identifying yourself (and your website) on the user-agent # USER_AGENT = 'csdn_hot_words (+http://www.yourdomain.com)' USER_AGENT = 'Mozilla/5.0'# Obey robots.txt rules ROBOTSTXT_OBEY = False# 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://docs.scrapy.org/en/latest/topics/settings.html#download-delay # See also autothrottle settings and docs DOWNLOAD_DELAY = 30 # 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','User-Agent': 'Mozilla/5.0 (Windows NT 6.2; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/27.0.1453.94 Safari/537.36' }# Enable or disable spider middlewares # See https://docs.scrapy.org/en/latest/topics/spider-middleware.html SPIDER_MIDDLEWARES = {'csdn_hot_words.middlewares.CsdnHotWordsSpiderMiddleware': 543, }# Enable or disable downloader middlewares # See https://docs.scrapy.org/en/latest/topics/downloader-middleware.html DOWNLOADER_MIDDLEWARES = {'csdn_hot_words.middlewares.CsdnHotWordsDownloaderMiddleware': 543, }# Enable or disable extensions # See https://docs.scrapy.org/en/latest/topics/extensions.html # EXTENSIONS = { # 'scrapy.extensions.telnet.TelnetConsole': None, # }# Configure item pipelines # See https://docs.scrapy.org/en/latest/topics/item-pipeline.html ITEM_PIPELINES = {'csdn_hot_words.pipelines.CsdnHotWordsPipeline': 300, }# Enable and configure the AutoThrottle extension (disabled by default) # See https://docs.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://docs.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'

執行主程序

可以通過scrapy的命令執行，但是為了看日志方便，加了一個主程序代碼。

#!/usr/bin/env python # -*- coding: utf-8 -*- # @Time : 2021/11/5 22:41 # @Author : 至尊寶 # @Site : # @File : main.py from scrapy import cmdlinecmdline.execute('scrapy crawl csdn'.split())

執行結果

執行部分日志

得到result.txt結果。

總結

看，java還是yyds。不知道為什么2021這個關鍵詞也可以排名靠前。于是我覺著把我標題也加上2021。

GitHub項目地址在發一遍：github本項目地址

申明一下，本文案例僅研究探索使用，不是為了惡意攻擊。

分享：

凡夫俗子不下苦功夫、死力氣去努力做成一件事，根本就沒資格去談什么天賦不天賦。

????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????——烽火戲諸侯《劍來》

如果本文對你有用的話，請不要吝嗇你的贊，謝謝。

?

總結

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