1.为什么写这个?
一些简单的页面,无需用比较大的框架来进行爬取,自己纯手写又比较麻烦
因此针对这个需求写了talonspider:
•1.针对单页面的item提取 - 具体介绍点这里
•2.spider模块 - 具体介绍点这里
2.介绍&&使用
2.1.item
这个模块是可以独立使用的,对于一些请求比较简单的网站(比如只需要get请求),单单只用这个模块就可以快速地编写出你想要的爬虫,比如(以下使用python3,python2见examples目录):
2.1.1.单页面单目标
比如要获取这个网址http://book.qidian.com/info/1004608738 的书籍信息,封面等信息,可直接这样写:
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import time
from talonspider import Item, TextField, AttrField
from pprint import pprint
class TestSpider(Item):
title = TextField(css_select = '.book-info>h1>em' )
author = TextField(css_select = 'a.writer' )
cover = AttrField(css_select = 'a#bookImg>img' , attr = 'src' )
def tal_title( self , title):
return title
def tal_cover( self , cover):
return 'http:' + cover
if __name__ = = '__main__' :
item_data = TestSpider.get_item(url = 'http://book.qidian.com/info/1004608738' )
pprint(item_data)
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2.1.1.单页面多目标
比如获取豆瓣250电影首页展示的25部电影,这一个页面有25个目标,可直接这样写:
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from talonspider import Item, TextField, AttrField
from pprint import pprint
# 定义继承自item的爬虫类
class DoubanSpider(Item):
target_item = TextField(css_select = 'div.item' )
title = TextField(css_select = 'span.title' )
cover = AttrField(css_select = 'div.pic>a>img' , attr = 'src' )
abstract = TextField(css_select = 'span.inq' )
def tal_title( self , title):
if isinstance (title, str ):
return title
else :
return ' '.join([i.text.strip().replace(' \xa0 ', ' ') for i in title])
if __name__ = = '__main__' :
items_data = DoubanSpider.get_items(url = 'https://movie.douban.com/top250' )
result = []
for item in items_data:
result.append({
'title' : item.title,
'cover' : item.cover,
'abstract' : item.abstract,
})
pprint(result)
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2.2.spider
当需要爬取有层次的页面时,比如爬取豆瓣250全部电影,这时候spider部分就派上了用场:
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# !/usr/bin/env python
from talonspider import Spider, Item, TextField, AttrField, Request
from talonspider.utils import get_random_user_agent
# 定义继承自item的爬虫类
class DoubanItem(Item):
target_item = TextField(css_select = 'div.item' )
title = TextField(css_select = 'span.title' )
cover = AttrField(css_select = 'div.pic>a>img' , attr = 'src' )
abstract = TextField(css_select = 'span.inq' )
def tal_title( self , title):
if isinstance (title, str ):
return title
else :
return ' '.join([i.text.strip().replace(' \xa0 ', ' ') for i in title])
class DoubanSpider(Spider):
# 定义起始url,必须
start_urls = [ 'https://movie.douban.com/top250' ]
# requests配置
request_config = {
'RETRIES' : 3 ,
'DELAY' : 0 ,
'TIMEOUT' : 20
}
# 解析函数 必须有
def parse( self , html):
# 将html转化为etree
etree = self .e_html(html)
# 提取目标值生成新的url
pages = [i.get( 'href' ) for i in etree.cssselect( '.paginator>a' )]
pages.insert( 0 , '?start=0&filter=' )
headers = {
"User-Agent" : get_random_user_agent()
}
for page in pages:
url = self .start_urls[ 0 ] + page
yield Request(url, request_config = self .request_config, headers = headers, callback = self .parse_item)
def parse_item( self , html):
items_data = DoubanItem.get_items(html = html)
# result = []
for item in items_data:
# result.append({
# 'title': item.title,
# 'cover': item.cover,
# 'abstract': item.abstract,
# })
# 保存
with open ( 'douban250.txt' , 'a+' ) as f:
f.writelines(item.title + '\n' )
if __name__ = = '__main__' :
DoubanSpider.start()
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控制台:
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/Users/howie/anaconda3/envs/work3/bin/python /Users/howie/Documents/programming/python/git/talonspider/examples/douban_page_by_spider.py
2017-06-07 23:17:30,346 - talonspider - INFO: talonspider started
2017-06-07 23:17:30,693 - talonspider_requests - INFO: GET a url: https://movie.douban.com/top250
2017-06-07 23:17:31,074 - talonspider_requests - INFO: GET a url: https://movie.douban.com/top250?start=25&filter=
2017-06-07 23:17:31,416 - talonspider_requests - INFO: GET a url: https://movie.douban.com/top250?start=50&filter=
2017-06-07 23:17:31,853 - talonspider_requests - INFO: GET a url: https://movie.douban.com/top250?start=75&filter=
2017-06-07 23:17:32,523 - talonspider_requests - INFO: GET a url: https://movie.douban.com/top250?start=100&filter=
2017-06-07 23:17:33,032 - talonspider_requests - INFO: GET a url: https://movie.douban.com/top250?start=125&filter=
2017-06-07 23:17:33,537 - talonspider_requests - INFO: GET a url: https://movie.douban.com/top250?start=150&filter=
2017-06-07 23:17:33,990 - talonspider_requests - INFO: GET a url: https://movie.douban.com/top250?start=175&filter=
2017-06-07 23:17:34,406 - talonspider_requests - INFO: GET a url: https://movie.douban.com/top250?start=200&filter=
2017-06-07 23:17:34,787 - talonspider_requests - INFO: GET a url: https://movie.douban.com/top250?start=225&filter=
2017-06-07 23:17:34,809 - talonspider - INFO: Time usage:0:00:04.462108
Process finished with exit code 0
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此时当前目录会生成douban250.txt,具体见douban_page_by_spider.py。
3.说明
学习之作,待完善的地方还有很多,欢迎提意见,项目地址talonspider。
原文链接:http://www.jianshu.com/p/c20b7f3d5a78