爬取xxx天气
爬取网址:https://tianqi.2345.com/today-60038.htm
安装
pip install scrapy
我使用的版本是scrapy 2.5
创建scray爬虫项目
在命令行如下输入命令
scrapy startproject name
name为项目名称
如,scrapy startproject spider_weather
之后再输入
scrapy genspider spider_name 域名
如,scrapy genspider changshu tianqi.2345.com
查看文件夹
- spider_weather
- spider
- __init__.py
- changshu.py
- __init__.py
- items.py
- middlewares.py
- pipelines.py
- settings.py
- scrapy.cfg
文件说明
名称 | 作用 |
---|---|
scrapy.cfg | 项目的配置信息,主要为Scrapy命令行工具提供一个基础的配置信息。(真正爬虫相关的配置信息在settings.py文件中) |
items.py | 设置数据存储模板,用于结构化数据,如:Django的Model |
pipelines | 数据处理行为,如:一般结构化的数据持久化 |
settings.py | 配置文件,如:递归的层数、并发数,延迟下载等 |
spiders | 爬虫目录,如:创建文件,编写爬虫规则 |
开始爬虫
1.在spiders文件夹里面对自己创建的爬虫文件进行数据爬取、如在此案例中的spiders/changshu.py
代码演示如下
import scrapy class ChangshuSpider(scrapy.Spider): name = 'changshu' allowed_domains = ['tianqi.2345.com'] start_urls = ['https://tianqi.2345.com/today-60038.htm'] def parse(self, response): # 日期、天气状态、温度、风级 # 利用xpath解析数据、不会xpath的同学可以去稍微学习一下,语法简单 dates = response.xpath('//a[@class="seven-day-item "]/em/text()').getall() states = response.xpath('//a[@class="seven-day-item "]/i/text()').getall() temps = response.xpath('//a[@class="seven-day-item "]/span[@class="tem-show"]/text()').getall() winds = response.xpath('//a[@class="seven-day-item "]/span[@class="wind-name"]/text()').getall() # 返回每条数据 for date, state, temp, wind in zip(dates,states,temps,winds): yield { 'date' : date, 'state': state, 'temp': temp, 'wind': wind }
2.在settings.py文件中进行配置
修改UA
USER_AGENT = 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/95.0.4638.69 Safari/537.36'
修改机器爬虫配置
ROBOTSTXT_OBEY = False
整个文件如下:
# Scrapy settings for spider_weather 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 = 'spider_weather' SPIDER_MODULES = ['spider_weather.spiders'] NEWSPIDER_MODULE = 'spider_weather.spiders' # Crawl responsibly by identifying yourself (and your website) on the user-agent USER_AGENT = 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/95.0.4638.69 Safari/537.36' # 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 = 3 # 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', #} # Enable or disable spider middlewares # See https://docs.scrapy.org/en/latest/topics/spider-middleware.html #SPIDER_MIDDLEWARES = { # 'spider_weather.middlewares.SpiderWeatherSpiderMiddleware': 543, #} # Enable or disable downloader middlewares # See https://docs.scrapy.org/en/latest/topics/downloader-middleware.html #DOWNLOADER_MIDDLEWARES = { # 'spider_weather.middlewares.SpiderWeatherDownloaderMiddleware': 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 = { # 'spider_weather.pipelines.SpiderWeatherPipeline': 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'
3.然后在命令行中输入如下代码
scrapy crawl changshu -o weather.csv
注意:需要进入spider_weather路径下运行
scrapy crawl 文件名 -o weather.csv(导出文件)
4.结果如下
补充:scrapy导出csv时字段的一些问题
scrapy -o csv格式输出的时候,发现输出文件中字段的顺序不是按照items.py中的顺序,也不是爬虫文件中写入的顺序,这样导出的数据因为某些字段变得不好看,此外,导出得csv文件不同的item之间被空行隔开,本文主要描述解决这些问题的方法。
1.字段顺序问题:
需要在scrapy的spiders同层目录,新建csv_item_exporter.py文件内容如下(文件名可改,目录定死)
from scrapy.conf import settings from scrapy.contrib.exporter import CsvItemExporter class MyProjectCsvItemExporter(CsvItemExporter): def init(self, *args, **kwargs): delimiter = settings.get(‘CSV_DELIMITER', ‘,') kwargs[‘delimiter'] = delimiter fields_to_export = settings.get(‘FIELDS_TO_EXPORT', []) if fields_to_export : kwargs[‘fields_to_export'] = fields_to_export super(MyProjectCsvItemExporter, self).init(*args, **kwargs)
2)在settings.py中新增以下内容
#定义输出格式 FEED_EXPORTERS = { ‘csv': ‘project_name.spiders.csv_item_exporter.MyProjectCsvItemExporter', } #指定csv输出字段的顺序 FIELDS_TO_EXPORT = [ ‘name', ‘title', ‘info' ] #指定分隔符 CSV_DELIMITER = ‘,'
设定完毕,执行scrapy crawl spider -o spider.csv的时候,字段就按顺序来了
2.输出csv有空行的问题
此时你可能会发现csv文件中有空行,这是因为scrapy默认输出时,每个item之间的分隔符是空行
解决办法:
在找到exporters.py的CsvItemExporter类,大概在215行中增加newline="",即可。
也可以继承重写CsvItemExporter类
总结
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