Scrapy

[uniquejava]

python environment = python interpreter + installed packages

pipenv详解

准备(pipenv, 这东西性能太差，已放弃，重回venv)

# 全局安装在pyenv下
$ pip install pipenv

# 创建一个隔离的python env （和virtualenv一样）

$ cd ~/gitibm/scrapy_tutorial
$ pipenv shell
✔ Successfully created virtual environment!
Virtualenv location: /Users/xxx/.local/share/virtualenvs/scrapy_tutorial-RsU7P9xB

# 配置pipenv使用阿里云镜像
$ vi Pipfile

[[source]]
name = "pypi"
url = "https://mirrors.aliyun.com/pypi/simple/"
verify_ssl = true

# 查看当前环境下installed packages
$ pipenv run pip freeze

# 安装依赖
$ pipenv install scrapy

新建项目

scrapy startproject book_crawler

book_crawler/
    scrapy.cfg   <-- Configuration file (DO NOT TOUCH!)
    tutorial/
        __init__.py              <-- Empty file that marks this as a Python folder
        items.py                 <-- Model of the item to scrap
        middlewares.py    <-- Scrapy processing hooks (DO NOT TOUCH)
        pipelines.py           <-- What to do with the scraped item
        settings.py             <-- Project settings file
        spiders/                  <-- Directory of our spiders (empty by now)
            __init__.py

新建爬虫

scrapy genspider fiction books.toscrape.com

# -*- coding: utf-8 -*-
import scrapy


class SpiderSpider(scrapy.Spider):
    name = 'fiction'
    allowed_domains = ['books.toscrape.com']
    start_urls = ['http://books.toscrape.com/']

    def parse(self, response):
        pass

运行

scrapy crawl fiction

保存

scrapy crawl fiction -o books.json
scrapy crawl fiction -o books.csv
scrapy crawl fiction -o books.xml

在控制台调式

$ scrapy shell 'http://books.toscrape.com/'
 >>> response.css(...)
 >>> response.xpath(...)

extract 相当于querySelectorAll， 返回list
extract_first相当于querySelector， 返回第一个匹配的元素

Rererences

1. Creating your first spider - 01 - Python scrapy tutorial for beginners