Scrapy：python3下的第一次運行測試

1，引言

《Scrapy的架構初探》一文講解了Scrapy的架構，本文就實際來安裝運行一下Scrapy爬蟲。本文以官網的tutorial作為例子，完整的代碼可以在github上下載。

2，運行環境配置

• 本次測試的環境是：Windows10， Python3.4.3 32bit
• 安裝Scrapy ：   $ pip install Scrapy                 #實際安裝時，由於服務器狀態的不穩定，出現好幾次中途退出的情況

3，編寫運行第一個Scrapy爬蟲

3.1. 生成一個新項目：tutorial

$ scrapy startproject tutorial

項目目錄結構如下：



3.2.  定義要抓取的item

# -*- coding: utf-8 -*-

# Define here the models for your scraped items
#
# See documentation in:
# http://doc.scrapy.org/en/latest/topics/items.html

import scrapy

class DmozItem(scrapy.Item): title = scrapy.Field() link = scrapy.Field() desc = scrapy.Field()

3.3. 定義Spider

import scrapy
from tutorial.items import DmozItem class DmozSpider(scrapy.Spider): name = "dmoz" allowed_domains = ["dmoz.org"] start_urls = [ "http://www.dmoz.org/Computers/Programming/Languages/Python/Books/", "http://www.dmoz.org/Computers/Programming/Languages/Python/Resources/" ] def parse(self, response): for sel in response.xpath('//ul/li'): item = DmozItem() item['title'] = sel.xpath('a/text()').extract() item['link'] = sel.xpath('a/@href').extract() item['desc'] = sel.xpath('text()').extract() yield item

3.4. 運行

$ scrapy crawl dmoz -o item.json

1) 結果報錯： 
   A) ImportError: cannot import name '_win32stdio'
   B) ImportError: No module named 'win32api'

2) 查錯過程：查看官方的FAQ和stackoverflow上的信息，原來是scrapy在python3上測試還不充分，還有小問題。

3) 解決過程：
   A) 需要手工去下載twisted/internet下的 _win32stdio 和 _pollingfile，存放到python目錄的lib\sitepackages\twisted\internet下
   B) 下載並安裝pywin32

再次運行，成功！在控制台上可以看到scrapy的輸出信息，待運行完成退出后，到項目目錄打開結果文件items.json， 可以看到里面以json格式存儲的爬取結果

[
{"title": ["        About       "], "desc": [" ", " "], "link": ["/docs/en/about.html"]}, {"title": [" Become an Editor "], "desc": [" ", " "], "link": ["/docs/en/help/become.html"]}, {"title": [" Suggest a Site "], "desc": [" ", " "], "link": ["/docs/en/add.html"]}, {"title": [" Help "], "desc": [" ", " "], "link": ["/docs/en/help/helpmain.html"]}, {"title": [" Login "], "desc": [" ", " "], "link": ["/editors/"]}, {"title": [], "desc": [" ", " Share via Facebook "], "link": []}, {"title": [], "desc": [" ", " Share via Twitter "], "link": []}, {"title": [], "desc": [" ", " Share via LinkedIn "], "link": []}, {"title": [], "desc": [" ", " Share via e-Mail "], "link": []}, {"title": [], "desc": [" ", " "], "link": []}, {"title": [], "desc": [" ", " "], "link": []}, {"title": [" About "], "desc": [" ", " "], "link": ["/docs/en/about.html"]}, {"title": [" Become an Editor "], "desc": [" ", " "], "link": ["/docs/en/help/become.html"]}, {"title": [" Suggest a Site "], "desc": [" ", " "], "link": ["/docs/en/add.html"]}, {"title": [" Help "], "desc": [" ", " "], "link": ["/docs/en/help/helpmain.html"]}, {"title": [" Login "], "desc": [" ", " "], "link": ["/editors/"]}, {"title": [], "desc": [" ", " Share via Facebook "], "link": []}, {"title": [], "desc": [" ", " Share via Twitter "], "link": []}, {"title": [], "desc": [" ", " Share via LinkedIn "], "link": []}, {"title": [], "desc": [" ", " Share via e-Mail "], "link": []}, {"title": [], "desc": [" ", " "], "link": []}, {"title": [], "desc": [" ", " "], "link": []} ]

第一次運行scrapy的測試成功

4，接下來的工作

接下來，我們將使用GooSeeker API來實現網絡爬蟲，省掉對每個item人工去生成和測試xpath的工作量。目前有2個計划：

• 在gsExtractor中封裝一個方法：從xslt內容中自動提取每個item的xpath
• 從gsExtractor的提取結果中自動提取每個item的結果

具體選擇哪個方案，將在接下來的實驗中確定，並發布到 gsExtractor新版本中

 

5，文檔修改歷史

 

2016-06-17：V1.0，首次發布