Python如何通过Scrapy框架实现爬取CSDN全站热榜标题热词
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小编给大家分享一下Python如何通过Scrapy框架实现爬取CSDN全站热榜标题热词，希望大家阅读完这篇文章之后都有所收获，下面让我们一起去探讨吧！
环境部署
scrapy安装
pip install scrapy -i https://pypi.douban.com/simpleselenium安装
pip install selenium -i https://pypi.douban.com/simplejieba安装
pip install jieba -i https://pypi.douban.com/simpleIDE：PyCharm
google chrome driver下载对应版本：google chrome driver下载地址
检查浏览器版本，下载对应版本。
实现过程
下面开始搞起。
创建项目
使用scrapy命令创建我们的项目。
scrapy startproject csdn_hot_words项目结构，如同官方给出的结构。
定义Item实体
按照之前的逻辑，主要属性为标题关键词对应出现次数的字典。代码如下：
# Define here the models for your scraped items## See documentation in:# https://docs.scrapy.org/en/latest/topics/items.html import scrapy class CsdnHotWordsItem(scrapy.Item): # define the fields for your item here like: # name = scrapy.Field() words = scrapy.Field()关键词提取工具
使用jieba分词获取工具。
#!/usr/bin/env python# -*- coding: utf-8 -*-# @Time : 2021/11/5 23:47# @Author : 至尊宝# @Site : # @File : analyse_sentence.py import jieba.analyse def 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] += 1 else: result_dic[word] = 1 return result_dic爬虫构造
这里需要给爬虫初始化一个浏览器参数，用来实现页面的动态加载。
#!/usr/bin/env python# -*- coding: utf-8 -*-# @Time : 2021/11/5 23:47# @Author : 至尊宝# @Site : # @File : csdn.py import scrapyfrom selenium import webdriverfrom selenium.webdriver.chrome.options import Options from csdn_hot_words.items import CsdnHotWordsItemfrom csdn_hot_words.tools.analyse_sentence import get_key_word class 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') # 使用无头谷歌浏览器模式 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代码说明
这里使用的是chrome的无头模式，就不需要有个浏览器打开再访问，都是后台执行的。
需要添加chromedriver的执行文件地址。
在parse的部分，可以参考之前我文章的xpath，获取到标题并且调用关键词提取，构造item对象。
中间件代码构造
添加js代码执行内容。中间件完整代码：
# Define here the models for your spider middleware## See documentation in:# https://docs.scrapy.org/en/latest/topics/spider-middleware.html from scrapy import signalsfrom scrapy.http import HtmlResponsefrom selenium.common.exceptions import TimeoutExceptionimport time from selenium.webdriver.chrome.options import Options # useful for handling different item types with a single interfacefrom itemadapter import is_item, ItemAdapter class 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. @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_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 None def 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 i def 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. pass def 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 r def 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. @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): js = ''' let height = 0 let 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('超时异常:{}'.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 IgnoreRequest return response def 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() chain pass def spider_opened(self, spider): spider.logger.info('Spider opened: %s' % spider.name)制作自定义pipeline
定义按照词频统计最终结果输出到文件。代码如下：
# 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 interfacefrom itemadapter import ItemAdapter class 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 item def 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()] += v else: key_word_dic[k.lower()] = v word_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
配置上要做一些调整。如下调整：
# 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.html BOT_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 rulesROBOTSTXT_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 docsDOWNLOAD_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.htmlSPIDER_MIDDLEWARES = { 'csdn_hot_words.middlewares.CsdnHotWordsSpiderMiddleware': 543,} # Enable or disable downloader middlewares# See https://docs.scrapy.org/en/latest/topics/downloader-middleware.htmlDOWNLOADER_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.htmlITEM_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'执行主程序
可以通过scrapy的命令执行，但是为了看日志方便，加了一个主程序代码。
#!/usr/bin/env python# -*- coding: utf-8 -*-# @Time : 2021/11/5 22:41# @Author : 至尊宝# @Site : # @File : main.pyfrom scrapy import cmdline cmdline.execute('scrapy crawl csdn'.split())执行结果
执行部分日志
得到result.txt结果。
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