python之Scrapy框架的第一个爬虫

执行：

D:\pycodes\python123demo>scrapy crawl demo

scrapy crawl demo

学习笔记：

代码：

D:\pycodes>scrapy startproject python123demo
New Scrapy project 'python123demo', using template directory 'c:\\users\\hwp\\appdata\\local\\programs\\python\\python37\\lib\\site-packages\\scrapy\\templates\\project', created in:
    D:\pycodes\python123demo

You can start your first spider with:
    cd python123demo
    scrapy genspider example example.com

D:\pycodes>

D:.
└─python123demo
    │  scrapy.cfg
    │
    └─python123demo
        │  items.py
        │  middlewares.py
        │  pipelines.py
        │  settings.py
        │  __init__.py
        │
        ├─spiders
        │  │  __init__.py
        │  │
        │  └─__pycache__
        └─__pycache__

代码：

D:\pycodes\python123demo>scrapy genspider demo python123.io
Created spider 'demo' using template 'basic' in module:
  python123demo.spiders.demo

会生成一个文件：​​demo.py​​

代码：

*# -- coding: utf-8 --*
import scrapy
class DemoSpider(scrapy.Spider):#类的名字：DemoSpider（叫啥都无所谓）  继承：scrapy.Spider
    name = 'demo'
    allowed_domains = ['python123.io']#最开始用户提交给命令行的域名：python123.io
    start_urls = ['http://python123.io/']#所要爬取页面的初始页面！

    def parse(self, response):#解析页面为空的方法！
        pass

产生步骤：

修改：
代码：

# -*- coding: utf-8 -*-
import scrapy
class DemoSpider(scrapy.Spider):
    name = 'demo'
    #allowed_domains = ['python123.io']
    start_urls = ['http://python123.io/ws/demo.html']

    def parse(self, response):
        fname = response.url.split('/')[-1]
        with open(fname, 'wb') as f:
            f.write(response.body)
        self.log('Save file %s.' % name)

执行：

D:\pycodes\python123demo>scrapy crawl demo

但是报错误！

不急解决办法：​​​​还要下载依赖：

链接：​​https://pypi.org/project/pywin32/#files​​

成功解决后：

demo.py代码的完整版本：与普通的对比！

yiled:啥意思呢~

学习笔记，不是技术文档~