从0到1教你用Python来爬取整站天气网

电玩女神 2023-02-14 01:44 85阅读 0赞

## 前言 ##

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作者：Python大数据分析

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--------------------

## 项目分析 ##

爬取天气网城市的信息

url : https://www.aqistudy.cn/historydata/

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2ZlaTM0Nzc5NTc5MA_size_16_color_FFFFFF_t_70]  
爬取主要的信息: 热门城市每一天的空气质量信息  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2ZlaTM0Nzc5NTc5MA_size_16_color_FFFFFF_t_70 1]  
点击月份还有爬取每天的空气质量信息  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2ZlaTM0Nzc5NTc5MA_size_16_color_FFFFFF_t_70 2]

## 新建项目 ##

*  新建文件夹命令为天气网爬虫
 *  `cd`到根目录，打开`cmd`，运行`scrapy startproject weather_spider`

![在这里插入图片描述][20200530160635300.png]

*  创建spider

cd到根目录,运行`scrapy genspider weather www.aqistudy.cn/historydata`  
![在这里插入图片描述][20200530161525264.png]  
这里的weather是spider的名字

*  创建的路径如下：  
    ![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2ZlaTM0Nzc5NTc5MA_size_16_color_FFFFFF_t_70 3]

## 代码编写 ##

对于scrapy，第一步，必须编写item.py，明确爬取的对象

*  **item.py**

import scrapy
    class WeatherSpiderItem(scrapy.Item):
        # define the fields for your item here like:
        # name = scrapy.Field()
        """日期 AQI 质量等级 PM2.5 PM10 SO2 CO NO2 O3_8h"""
        city = scrapy.Field()
        date = scrapy.Field()
        aqi = scrapy.Field()
        level = scrapy.Field()
        pm25 = scrapy.Field()
        pm10 = scrapy.Field()
        so2 = scrapy.Field()
        co = scrapy.Field()
        no2 = scrapy.Field()
        o3_8h = scrapy.Field()

对于爬取必须伪装好UA，在setting.py中定义MY\_USER\_AGENT来存放UA，注意在settings中命名必须大写

*  **settings.py**

MY_USER_AGENT = [
        "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1; AcooBrowser; .NET CLR 1.1.4322; .NET CLR 2.0.50727)",
        "Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.0; Acoo Browser; SLCC1; .NET CLR 2.0.50727; Media Center PC 5.0; .NET CLR 3.0.04506)",
        "Mozilla/4.0 (compatible; MSIE 7.0; AOL 9.5; AOLBuild 4337.35; Windows NT 5.1; .NET CLR 1.1.4322; .NET CLR 2.0.50727)",
        "Mozilla/5.0 (Windows; U; MSIE 9.0; Windows NT 9.0; en-US)",
        "Mozilla/5.0 (compatible; MSIE 9.0; Windows NT 6.1; Win64; x64; Trident/5.0; .NET CLR 3.5.30729; .NET CLR 3.0.30729; .NET CLR 2.0.50727; Media Center PC 6.0)",
        "Mozilla/5.0 (compatible; MSIE 8.0; Windows NT 6.0; Trident/4.0; WOW64; Trident/4.0; SLCC2; .NET CLR 2.0.50727; .NET CLR 3.5.30729; .NET CLR 3.0.30729; .NET CLR 1.0.3705; .NET CLR 1.1.4322)",
        "Mozilla/4.0 (compatible; MSIE 7.0b; Windows NT 5.2; .NET CLR 1.1.4322; .NET CLR 2.0.50727; InfoPath.2; .NET CLR 3.0.04506.30)",
        "Mozilla/5.0 (Windows; U; Windows NT 5.1; zh-CN) AppleWebKit/523.15 (KHTML, like Gecko, Safari/419.3) Arora/0.3 (Change: 287 c9dfb30)",
        "Mozilla/5.0 (X11; U; Linux; en-US) AppleWebKit/527+ (KHTML, like Gecko, Safari/419.3) Arora/0.6",
        "Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8.1.2pre) Gecko/20070215 K-Ninja/2.1.1",
        "Mozilla/5.0 (Windows; U; Windows NT 5.1; zh-CN; rv:1.9) Gecko/20080705 Firefox/3.0 Kapiko/3.0",
        "Mozilla/5.0 (X11; Linux i686; U;) Gecko/20070322 Kazehakase/0.4.5",
        "Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.0.8) Gecko Fedora/1.9.0.8-1.fc10 Kazehakase/0.5.6",
        "Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/535.11 (KHTML, like Gecko) Chrome/17.0.963.56 Safari/535.11",
        "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_7_3) AppleWebKit/535.20 (KHTML, like Gecko) Chrome/19.0.1036.7 Safari/535.20",
        "Opera/9.80 (Macintosh; Intel Mac OS X 10.6.8; U; fr) Presto/2.9.168 Version/11.52",
        "Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/536.11 (KHTML, like Gecko) Chrome/20.0.1132.11 TaoBrowser/2.0 Safari/536.11",
        "Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.1 (KHTML, like Gecko) Chrome/21.0.1180.71 Safari/537.1 LBBROWSER",
        "Mozilla/5.0 (compatible; MSIE 9.0; Windows NT 6.1; WOW64; Trident/5.0; SLCC2; .NET CLR 2.0.50727; .NET CLR 3.5.30729; .NET CLR 3.0.30729; Media Center PC 6.0; .NET4.0C; .NET4.0E; LBBROWSER)",
        "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1; QQDownload 732; .NET4.0C; .NET4.0E; LBBROWSER)",
        "Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/535.11 (KHTML, like Gecko) Chrome/17.0.963.84 Safari/535.11 LBBROWSER",
        "Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.1; WOW64; Trident/5.0; SLCC2; .NET CLR 2.0.50727; .NET CLR 3.5.30729; .NET CLR 3.0.30729; Media Center PC 6.0; .NET4.0C; .NET4.0E)",
        "Mozilla/5.0 (compatible; MSIE 9.0; Windows NT 6.1; WOW64; Trident/5.0; SLCC2; .NET CLR 2.0.50727; .NET CLR 3.5.30729; .NET CLR 3.0.30729; Media Center PC 6.0; .NET4.0C; .NET4.0E; QQBrowser/7.0.3698.400)",
        "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1; QQDownload 732; .NET4.0C; .NET4.0E)",
        "Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 5.1; Trident/4.0; SV1; QQDownload 732; .NET4.0C; .NET4.0E; 360SE)",
        "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1; QQDownload 732; .NET4.0C; .NET4.0E)",
        "Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.1; WOW64; Trident/5.0; SLCC2; .NET CLR 2.0.50727; .NET CLR 3.5.30729; .NET CLR 3.0.30729; Media Center PC 6.0; .NET4.0C; .NET4.0E)",
        "Mozilla/5.0 (Windows NT 5.1) AppleWebKit/537.1 (KHTML, like Gecko) Chrome/21.0.1180.89 Safari/537.1",
        "Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.1 (KHTML, like Gecko) Chrome/21.0.1180.89 Safari/537.1",
        "Mozilla/5.0 (iPad; U; CPU OS 4_2_1 like Mac OS X; zh-cn) AppleWebKit/533.17.9 (KHTML, like Gecko) Version/5.0.2 Mobile/8C148 Safari/6533.18.5",
        "Mozilla/5.0 (Windows NT 6.1; Win64; x64; rv:2.0b13pre) Gecko/20110307 Firefox/4.0b13pre",
        "Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:16.0) Gecko/20100101 Firefox/16.0",
        "Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.11 (KHTML, like Gecko) Chrome/23.0.1271.64 Safari/537.11",
        "Mozilla/5.0 (X11; U; Linux x86_64; zh-CN; rv:1.9.2.10) Gecko/20100922 Ubuntu/10.10 (maverick) Firefox/3.6.10",
        "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.110 Safari/537.36",
    ]

在定义好UA后，在middlewares.py中创建RandomUserAgentMiddleware类

*  **middlewares.py**

import random
    class RandomUserAgentMiddleware(object):
        def __init__(self, user_agents):
            self.user_agents = user_agents
    
        @classmethod
        def from_crawler(cls, crawler):
            # 从settings.py中导入MY_USER_AGENT
            s = cls(user_agents=crawler.settings.get('MY_USER_AGENT'))
            return s
    
        def process_request(self, request, spider):
            agent = random.choice(self.user_agents)
            request.headers['User-Agent'] = agent
            return None

开始编写最重要的spider.py，推荐使用scrapy.shell来一步一步调试

*  **先拿到所有的城市**

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2ZlaTM0Nzc5NTc5MA_size_16_color_FFFFFF_t_70 4]  
在scrapy中xpath方法和lxml中的xpath语法一样  
![在这里插入图片描述][2020053016271396.png]  
我们可以看出url中缺少前面的部分，follow方法可以自动拼接url,通过meta方法来传递需要保存的city名字，通过callback方法来调度将下一个爬取的URL

*  **weather.py**

def parse(self, response):
        city_urls = response.xpath('//div[@class="all"]/div[@class="bottom"]//li/a/@href').extract()[16:17]
        city_names = response.xpath('//div[@class="all"]/div[@class="bottom"]//li/a/text()').extract()[16:17]
        self.logger.info('正在爬去{}城市url'.format(city_names[0]))
        for city_url, city_name in zip(city_urls, city_names):
            # 用的follow快捷方式，可以自动拼接url
            yield response.follow(url=city_url, meta={ 'city': city_name}, callback=self.parse_month)

这时就是定义parse\_month函数，首先分析月份的详情页,拿到月份的url  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2ZlaTM0Nzc5NTc5MA_size_16_color_FFFFFF_t_70 5]  
还是在scrapy.shell 中一步一步调试  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2ZlaTM0Nzc5NTc5MA_size_16_color_FFFFFF_t_70 6]  
通过follow方法拼接url，meta来传递city\_name要保存的城市名字，selenium：True先不管  
然后通过callback方法来调度将下一个爬取的URL，即就是天的爬取详细页

*  **weather.py**

def parse_month(self, response):
        """ 解析月份的url :param response: :return: """
        city_name = response.meta['city']
        self.logger.info('正在爬取{}城市的月份url'.format(city_name[0]))
        # 由于爬取的信息太大了，所有先爬取前5个
        month_urls = response.xpath('//ul[@class="unstyled1"]/li/a/@href').extract()[0:5]
        for month_url in month_urls:
            yield response.follow(url=month_url, meta={ 'city': city_name, 'selenium': True}, callback=self.parse_day_data)

现在将日的详细页的信息通过xpah来取出  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2ZlaTM0Nzc5NTc5MA_size_16_color_FFFFFF_t_70 7]  
发现竟然为空  
![在这里插入图片描述][20200530162822467.png]  
同时发现了源代码没有该信息  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2ZlaTM0Nzc5NTc5MA_size_16_color_FFFFFF_t_70 8]  
说明了是通过js生成的数据，scrapy只能爬静态的信息，所以引出的scrapy对接selenium的知识点，所以上面meta传递的参数就是告诉scrapy使用selenium来爬取。

复写`WeatherSpiderDownloaderMiddleware`下载中间件中的process\_request函数方法

*  **middlewares.py**

import time
    import scrapy
    from selenium import webdriver
    from selenium.webdriver.chrome.options import Options
    class WeatherSpiderDownloaderMiddleware(object):
        def process_request(self, request, spider):
            if request.meta.get('selenium'):
                # 为了让浏览器能够无界面的工作
                chrome_options = Options()
                # 设置chrome浏览器无界面模式
                chrome_options.add_argument('--headless')
                driver = webdriver.Chrome(chrome_options=chrome_options)
                # 用浏览器去访问这个地址
                driver.get(request.url)
                time.sleep(1.5)  # 因为浏览器需要加载渲染
                html = driver.page_source
                driver.quit()
                return scrapy.http.HtmlResponse(url=request.url, body=html, encoding='utf-8', request=request)
            return None

激活WeatherSpiderDownloaderMiddleware

DOWNLOADER_MIDDLEWARES = { 
       'weather_spider.middlewares.WeatherSpiderDownloaderMiddleware': 543,
       'weather_spider.middlewares.RandomUserAgentMiddleware':900,
    }

最后编写weather.py中的剩下代码

from ..items import WeatherSpiderItem
    def parse_day_data(self, response):
        """ 解析每天的数据 :param response: :return: """
    
        node_list = response.xpath('//tr')
        # 去掉表头
        node_list.pop(0)
        print(response.body)
        print('开始爬取……')
        print(node_list)
        for node in node_list:
            item = WeatherSpiderItem
            item['city'] = response.meta['city']
            item['date'] = node.xpath('./td[1]/text()').extract_first()
            item['aqi'] = node.xpath('./td[2]/text()').extract_first()
            item['level'] = node.xpath('./td[3]//text()').extract_first()
            item['pm25'] = node.xpath('./td[4]/text()').extract_first()
            item['pm10'] = node.xpath('./td[5]/text()').extract_first()
            item['so2'] = node.xpath('./td[6]/text()').extract_first()
            item['co'] = node.xpath('./td[7]/text()').extract_first()
            item['no2'] = node.xpath('./td[8]/text()').extract_first()
            item['o3_8h'] = node.xpath('./td[9]/text()').extract_first()
            yield item

## 入库操作 ##

这里入的库是Mongodb，在settings.py中配置

MONGO_URI='192.168.96.128' #虚拟机ip
    MONGO_DB='weather' #表名

对于入门主要处理的是pipelines中

*  **pipelines.py**

import pymongo
    
    class MongoPipeline(object):
        def __init__(self,mongo_uri,mongo_db):
            self.mongo_uri=mongo_uri
            self.mongo_db=mongo_db
    
        @classmethod
        def from_crawler(cls, crawler):
            return cls(
                mongo_uri=crawler.settings.get('MONGO_URI'),
                mongo_db=crawler.settings.get('MONGO_DB')
            )
    
        def open_spider(self, spider):  # 当爬虫开启时连接MongoDB数据库
            self.client = pymongo.MongoClient(self.mongo_uri)
            self.db = self.client[self.mongo_db]
    
        def process_item(self, item, spider):
            name = item.__class__.__name__
            self.db[name].insert(dict(item))  # 保存数据
            return item
    
        def close_spider(self, spider):  # 当爬虫关闭时关闭数据库连接
            self.client.close()

在settings中激活pipelines

ITEM_PIPELINES = { 
       'weather_spider.pipelines.MongoPipeline': 300,
    }

效果如下  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2ZlaTM0Nzc5NTc5MA_size_16_color_FFFFFF_t_70 9]

[python]: https://jq.qq.com/?_wv=1027&k=ThcV4SNF
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2ZlaTM0Nzc5NTc5MA_size_16_color_FFFFFF_t_70]: https://img-blog.csdnimg.cn/20200530160551849.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2ZlaTM0Nzc5NTc5MA==,size_16,color_FFFFFF,t_70
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2ZlaTM0Nzc5NTc5MA_size_16_color_FFFFFF_t_70 1]: https://img-blog.csdnimg.cn/20200530160602751.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2ZlaTM0Nzc5NTc5MA==,size_16,color_FFFFFF,t_70
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2ZlaTM0Nzc5NTc5MA_size_16_color_FFFFFF_t_70 2]: https://img-blog.csdnimg.cn/20200530160610817.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2ZlaTM0Nzc5NTc5MA==,size_16,color_FFFFFF,t_70
[20200530160635300.png]: https://img-blog.csdnimg.cn/20200530160635300.png
[20200530161525264.png]: https://img-blog.csdnimg.cn/20200530161525264.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2ZlaTM0Nzc5NTc5MA_size_16_color_FFFFFF_t_70 3]: https://img-blog.csdnimg.cn/20200530161546483.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2ZlaTM0Nzc5NTc5MA==,size_16,color_FFFFFF,t_70
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2ZlaTM0Nzc5NTc5MA_size_16_color_FFFFFF_t_70 4]: https://img-blog.csdnimg.cn/20200530162456290.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2ZlaTM0Nzc5NTc5MA==,size_16,color_FFFFFF,t_70
[2020053016271396.png]: https://img-blog.csdnimg.cn/2020053016271396.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2ZlaTM0Nzc5NTc5MA_size_16_color_FFFFFF_t_70 5]: https://img-blog.csdnimg.cn/20200530162739784.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2ZlaTM0Nzc5NTc5MA==,size_16,color_FFFFFF,t_70
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2ZlaTM0Nzc5NTc5MA_size_16_color_FFFFFF_t_70 6]: https://img-blog.csdnimg.cn/20200530162750555.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2ZlaTM0Nzc5NTc5MA==,size_16,color_FFFFFF,t_70
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2ZlaTM0Nzc5NTc5MA_size_16_color_FFFFFF_t_70 7]: https://img-blog.csdnimg.cn/2020053016281424.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2ZlaTM0Nzc5NTc5MA==,size_16,color_FFFFFF,t_70
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