scrapy初学习--爬取豆瓣新片榜

喜欢ヅ旅行 2022-01-11 05:41 314阅读 0赞

### 文章目录 ###

*   *   *  爬取豆瓣榜单遇到403错误
         *  效果
         *  元素选择
         *  代码

### 爬取豆瓣榜单遇到403错误 ###

如图  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dqaDI2MjIwNzUxMjc_size_16_color_FFFFFF_t_70]  
**解决方法**:  
**在setting.py中添加user agent**  
`USER_AGENT = 'Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/55.0.2883.87 Safari/537.36'`

爬取成功  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dqaDI2MjIwNzUxMjc_size_16_color_FFFFFF_t_70 1]

### 效果 ###

这是新片榜  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dqaDI2MjIwNzUxMjc_size_16_color_FFFFFF_t_70 2]  
爬取结果  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dqaDI2MjIwNzUxMjc_size_16_color_FFFFFF_t_70 3]

### 元素选择 ###

使用xpath进行元素选择.

from lxml import etree
    
    html = etree.parse('./douban.html', etree.HTMLParser())
    result = html.xpath('//tr/td/a/@title') # 获取a节点的title属性
    # result = html.xpath('//tr/td/a[@class='test']') # 获取a节点且class为test的元素
    print(result)
    
    test2 = html.xpath('//div[@class="star clearfix"]/span[@class="rating_nums"]/text()')
    print(test2)

### 代码 ###

scrapy对url的爬取可以并行的, 也就是说第二个url不用等第一个爬完, 也不会相互影响.

建立scrapy项目之后, 在spiders目录下新建自己的爬虫代码py文件.  
写好后, 使用命令`scrapy crawl douban_chat`执行

代码如下

import scrapy
    import re
    
    class QuotesSpider(scrapy.Spider):
        name = "douban_chat" # 爬虫名字, 在命令行下会用到
    
        def start_requests(self):
            urls = [
                'https://movie.douban.com/chart',
            ]
            for url in urls:
                yield scrapy.Request(url=url, callback=self.parse)
    
        def parse(self, response):
            # xpath 选择器 + 正则表达式找出电影标题和评分
            titles_raw = response.xpath('//div/table/tr').getall()
            titles = ""
            for each in titles_raw:
                try:
                    title = re.findall(r'title="(.+)">', each)[0]
                    score = re.findall(r'rating_nums">(.+)</span>', each)[0]
                    titles += title + " : " + score + '\n'
                except:
                    pass
    
            page = response.url.split("/")[-2]
            filename = '%s.html' % page
            with open(filename, 'w+', encoding='utf-8') as f:
                f.write(titles)
            self.log('Saved file %s' % filename)

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