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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环境部署

scrapy安装

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

selenium安装

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

jieba安装

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

IDE：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

1、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。

2、需要添加chromedriver的执行文件地址。

3、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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