【Python爬虫8】Scrapy 爬虫框架

1.安装Scrapy

用pip命令安装Scrapy：pip install Scrapy

wu_being@ubuntukylin64:~/GitHub/WebScrapingWithPython$ scrapy -hScrapy 1.3.0 - no active projectUsage:  scrapy <command> [options] [args]Available commands:  bench         Run quick benchmark test  commands        fetch         Fetch a URL using the Scrapy downloader  genspider     Generate new spider using pre-defined templates  runspider     Run a self-contained spider (without creating a project)  settings      Get settings values  shell         Interactive scraping console  startproject  Create new project  version       Print Scrapy version  view          Open URL in browser, as seen by Scrapy  [ more ]      More commands available when run from project directoryUse "scrapy <command> -h" to see more info about a commandwu_being@ubuntukylin64:~/GitHub/WebScrapingWithPython$ 

本篇会用到下面几个命令：
- startproject：创建一人新项目
- genspider：根据模板生成一个新爬虫
- crawl：执行爬虫
- shell：启动交互式提取控制台

文档：http://doc.scrapy.org/latest/topics/commands.html

2.新建项目

输入scrapy startproject <project_name>新建项目，这里使用example_wu为项目名。

wu_being@ubuntukylin64:~/GitHub/WebScrapingWithPython/8.Scrapy爬虫框架$ scrapy startproject Usage=====  scrapy startproject <project_name> [project_dir]...wu_being@ubuntukylin64:~/GitHub/WebScrapingWithPython/8.Scrapy爬虫框架$ scrapy startproject example_wuNew Scrapy project 'example_wu', using template directory '/usr/local/lib/python2.7/dist-packages/scrapy/templates/project', created in:    /home/wu_being/GitHub/WebScrapingWithPython/8.Scrapy爬虫框架/example_wuYou can start your first spider with:    cd example_wu    scrapy genspider example example.comwu_being@ubuntukylin64:~/GitHub/WebScrapingWithPython/8.Scrapy爬虫框架/example_wu$ lsexample_wu  scrapy.cfgwu_being@ubuntukylin64:~/GitHub/WebScrapingWithPython/8.Scrapy爬虫框架/example_wu$ 

下面是新建项目的默认目录结构：

scrapy.cfgexample_wu/    __init__.py    items.py    middlewares.py    pipelines.py    setting.py    spiders/        __init__.py

下面是重要的几个文件说明：
- scrapy.cfg：设置项目配置（不用修改）
- items.py：定义待提取域的模型
- pipelines.py：处理要提取的域（不用修改）
- setting.py：定义一些设置，如用户代理、提取延时等
- spiders/：该目录存储实际的爬虫代码

2.1定义模型

example_wu/items.py默认代码如下：

# -*- coding: utf-8 -*-# Define here the models for your scraped items## See documentation in:# http://doc.scrapy.org/en/latest/topics/items.htmlimport scrapyclass ExampleWuItem(scrapy.Item):    # define the fields for your item here like:    # name = scrapy.Field()    pass

ExampleWuItem类是一个模板，需要将其中的内容替换为爬虫运行时想要存储的待提取的国家信息，我们这里设置只提取国家名称和人口数量，把默认代码修改为：

import scrapyclass ExampleWuItem(scrapy.Item):    # define the fields for your item here like:    name = scrapy.Field()    population=scrapy.Field()

2.2创建爬虫

现在我们开始编写真正的爬虫代码，又称为spider，通过genspider命令，传入爬虫名、域名和可选模板参数：
scrapy genspider country 127.0.0.1:8000/places --template=crawl

wu_being@ubuntukylin64:~/GitHub/WebScrapingWithPython/8.Scrapy爬虫框架/example_wu$ scrapy genspideUsage=====  scrapy genspider [options] <name> <domain>Generate new spider using pre-defined templatesOptions=======--help, -h              show this help message and exit--list, -l              List available templates--edit, -e              Edit spider after creating it--dump=TEMPLATE, -d TEMPLATE                        Dump template to standard output--template=TEMPLATE, -t TEMPLATE                        Uses a custom template.--force                 If the spider already exists, overwrite it with the                        template...wu_being@ubuntukylin64:~/GitHub/WebScrapingWithPython/8.Scrapy爬虫框架/example_wu$ scrapy genspider --listAvailable templates:  basic  crawl  csvfeed  xmlfeedwu_being@ubuntukylin64:~/GitHub/WebScrapingWithPython/8.Scrapy爬虫框架/example_wu$ scrapy genspider country 127.0.0.1:8000/places --template=crawlCreated spider 'country' using template 'crawl' in module:  example_wu.spiders.countrywu_being@ubuntukylin64:~/GitHub/WebScrapingWithPython/8.Scrapy爬虫框架/example_wu$

这里使用内置crawl模板，可以生成更加接近我们想要的国家爬虫初始版本。运行genspider命令之后，将会生成代码example_wu/spiders/country.py。

# -*- coding: utf-8 -*-import scrapyfrom scrapy.linkextractors import LinkExtractorfrom scrapy.spiders import CrawlSpider, Ruleclass CountrySpider(CrawlSpider):    name = 'country'    #allowed_domains = ['127.0.0.1:8000/places'] ###!!!!这个不是域名    start_urls = ['http://127.0.0.1:8000/places/']    rules = (        Rule(LinkExtractor(allow=r'Items/'), callback='parse_item', follow=True),    )    def parse_item(self, response):        i = {}        #i['domain_id'] = response.xpath('//input[@id="sid"]/@value').extract()        #i['name'] = response.xpath('//div[@id="name"]').extract()        #i['description'] = response.xpath('//div[@id="description"]').extract()        return i

该类的属性名：
- name：定义爬虫的名称
- allowed_domains：定义可以提取的域名列表。如果没有则表示可以提取任何域名!!!!!!
- start_urls：定义爬虫起始的URL列表。意思为可用的URL!!!!!!
- rules：定义正则表达式集合，用于告知爬虫需要跟踪哪些链接。还有一个callback函数，用于解析下载得到的响应，而parse_urls()示例方法给我们提供了一个从响应中获取数据的例子。

文档：http://doc.scrapy.org/en/latest/topics/spiders.html

2.3优化设置

默认情况下，Scrapy对同一个域名允许最多16个并发下载，并且再次下载之间没有延时，这样爬虫容易被服务器检测到并被封禁，所以要在example_wu/settings.py添加几行代码：

# Configure maximum concurrent requests performed by Scrapy (default: 16)#CONCURRENT_REQUESTS = 32# Configure a delay for requests for the same website (default: 0)# See http://scrapy.readthedocs.org/en/latest/topics/settings.html#download-delay# See also autothrottle settings and docsDOWNLOAD_DELAY = 5# The download delay setting will honor only one of:CONCURRENT_REQUESTS_PER_DOMAIN = 1#CONCURRENT_REQUESTS_PER_IP = 16

这里的延时不是精确的，精确的延时有时也可能被服务器检测到被封禁，而Scrapy实际在两次请求的延时添加随机的偏移量。文档：http://doc.scrapy.org/en/latest/topics/settings.html

2.4测试爬虫

使用crawl运行爬虫，并附上爬虫名称。

wu_being@ubuntukylin64:~/GitHub/WebScrapingWithPython/8.Scrapy爬虫框架/example_wu$ scrapy crawl country -s LOG_LEVEL=ERRORwu_being@ubuntukylin64:~/GitHub/WebScrapingWithPython/8.Scrapy爬虫框架/example_wu$ 

发现终端日志没有输出错误信息，命令的参数LOG_LEVEL=ERROR等同于在settings.py加一行LOG_LEVEL='ERROR'，默认是在终端显示所有日志信息。

rules = (    Rule(LinkExtractor(allow='/index/'), follow=True),    Rule(LinkExtractor(allow='/view/'), callback='parse_item'),)

上面我们添加了两条规则。第一条规则爬取索引页并跟踪其中的链接(递归爬取链接，默认是True)，而第二条规则爬取国家页面并将下载响应传给callback函数用于提取数据。

...2017-01-30 00:12:47 [scrapy.core.engine] DEBUG: Crawled (200) <GET http://127.0.0.1:8000/places/> (referer: None)2017-01-30 00:12:52 [scrapy.core.engine] DEBUG: Crawled (200) <GET http://127.0.0.1:8000/places/default/view/Afghanistan-1> (referer: http://127.0.0.1:8000/places/)2017-01-30 00:12:57 [scrapy.core.engine] DEBUG: Crawled (200) <GET http://127.0.0.1:8000/places/default/index/1> (referer: http://127.0.0.1:8000/places/)2017-01-30 00:12:58 [scrapy.dupefilters] DEBUG: Filtered duplicate request: <GET http://127.0.0.1:8000/places/default/index/1> - no more duplicates will be shown (see DUPEFILTER_DEBUG to show all duplicates)2017-01-30 00:13:03 [scrapy.core.engine] DEBUG: Crawled (200) <GET http://127.0.0.1:8000/places/default/view/Antigua-and-Barbuda-10> (referer: http://127.0.0.1:8000/places/)......2017-01-30 00:14:11 [scrapy.core.engine] DEBUG: Crawled (200) <GET http://127.0.0.1:8000/places/default/user/login?_next=%2Fplaces%2Fdefault%2Findex%2F1> (referer: http://127.0.0.1:8000/places/default/index/1)2017-01-30 00:14:17 [scrapy.core.engine] DEBUG: Crawled (200) <GET http://127.0.0.1:8000/places/default/user/register?_next=%2Fplaces%2Fdefault%2Findex%2F1> (referer: http://127.0.0.1:8000/places/default/index/1)......

我们发现已经自动过滤了重复链接，但结果有多余的登录页和注册页，我们可以用正则表达式过滤。

rules = (    Rule(LinkExtractor(allow='/index/', deny='/user/'), follow=True), #False    Rule(LinkExtractor(allow='/view/', deny='/user/'), callback='parse_item'),)

使用该类的文档：http://doc.scrapy.org/en/latest/topics/linkextractors.html

2.5使用shell命令提取数据

scrapy提供了shell命令可以下载URL并在python解释器中给出结果状态。

wu_being@ubuntukylin64:~/GitHub/WebScrapingWithPython/8.Scrapy爬虫框架/example_wu$ scrapy shell http://127.0.0.1:8000/places/default/view/47...2017-01-30 11:24:21 [scrapy.core.engine] INFO: Spider opened2017-01-30 11:24:21 [scrapy.core.engine] DEBUG: Crawled (400) <GET http://127.0.0.1:8000/robots.txt> (referer: None)2017-01-30 11:24:22 [scrapy.core.engine] DEBUG: Crawled (200) <GET http://127.0.0.1:8000/places/default/view/47> (referer: None)[s] Available Scrapy objects:[s]   scrapy     scrapy module (contains scrapy.Request, scrapy.Selector, etc)[s]   crawler    <scrapy.crawler.Crawler object at 0x7fd8e6d5cbd0>[s]   item       {}[s]   request    <GET http://127.0.0.1:8000/places/default/view/47>[s]   response   <200 http://127.0.0.1:8000/places/default/view/47>[s]   settings   <scrapy.settings.Settings object at 0x7fd8e6d5c5d0>[s]   spider     <DefaultSpider 'default' at 0x7fd8e5b24c50>[s] Useful shortcuts:[s]   fetch(url[, redirect=True]) Fetch URL and update local objects (by default, redirects are followed)[s]   fetch(req)                  Fetch a scrapy.Request and update local objects [s]   shelp()           Shell help (print this help)[s]   view(response)    View response in a browser>>> 

下面我们来测试一下。

>>> >>> response<200 http://127.0.0.1:8000/places/default/view/47>>>> response.url'http://127.0.0.1:8000/places/default/view/47'>>> response.status200>>> item{}>>> >>> 

scrapy可以使用lxml提取数据，这里用CSS选择器。用extract()提取数据。

>>> response.css('#places_country__row > td.w2p_fw::text')[<Selector xpath=u"descendant-or-self::*[@id = 'places_country__row']/td[@class and contains(concat(' ', normalize-space(@class), ' '), ' w2p_fw ')]/text()" data=u'China'>]>>> name_css='#places_country__row > td.w2p_fw::text'>>> response.css(name_css)[<Selector xpath=u"descendant-or-self::*[@id = 'places_country__row']/td[@class and contains(concat(' ', normalize-space(@class), ' '), ' w2p_fw ')]/text()" data=u'China'>]>>> response.css(name_css).extract()[u'China']>>> >>> pop_css='#places_population__row > td.w2p_fw::text'>>> response.css(pop_css).extract()[u'1330044000']>>> 

2.6提取数据保存到文件中

下面是该爬虫的完整代码。

# -*- coding: utf-8 -*-import scrapyfrom scrapy.linkextractors import LinkExtractorfrom scrapy.spiders import CrawlSpider, Rulefrom example_wu.items import ExampleWuItem ###wuclass CountrySpider(CrawlSpider):    name = 'country'    #allowed_domains = ['127.0.0.1:8000/places']####domains!!!!这个不是域名    start_urls = ['http://127.0.0.1:8000/places/']    rules = (        Rule(LinkExtractor(allow='/index/', deny='/user/'), follow=True), #False        Rule(LinkExtractor(allow='/view/', deny='/user/'), callback='parse_item'),    )    def parse_item(self, response):        item = ExampleWuItem() ###wu        item['name'] = response.css('tr#places_country__row td.w2p_fw::text').extract()        item['population'] = response.css('tr#places_population__row td.w2p_fw::text').extract()        return item

要想保存结果，我们可以在parse_item()方法中添加保存提取数据的代码，或是定义管道。不过scrapy提供了一个方便的--output选项，用于自动保存提取的数据到CSV、JSON和XML文件中。

wu_being@ubuntukylin64:~/GitHub/WebScrapingWithPython/8.Scrapy爬虫框架/example_wu$ scrapy crawl country -s LOG_LEVEL=DEBUG2017-01-30 13:09:52 [scrapy.utils.log] INFO: Scrapy 1.3.0 started (bot: example_wu)...2017-01-30 13:09:52 [scrapy.middleware] INFO: Enabled item pipelines:[]2017-01-30 13:09:52 [scrapy.core.engine] INFO: Spider opened2017-01-30 13:09:52 [scrapy.extensions.logstats] INFO: Crawled 0 pages (at 0 pages/min), scraped 0 items (at 0 items/min)2017-01-30 13:09:52 [scrapy.extensions.telnet] DEBUG: Telnet console listening on 127.0.0.1:60232017-01-30 13:09:52 [scrapy.core.engine] DEBUG: Crawled (400) <GET http://127.0.0.1:8000/robots.txt> (referer: None)2017-01-30 13:09:53 [scrapy.core.engine] DEBUG: Crawled (200) <GET http://127.0.0.1:8000/places/> (referer: None)2017-01-30 13:09:53 [scrapy.core.engine] DEBUG: Crawled (200) <GET http://127.0.0.1:8000/places/default/view/Afghanistan-1> (referer: http://127.0.0.1:8000/places/)2017-01-30 13:09:53 [scrapy.core.scraper] DEBUG: Scraped from <200 http://127.0.0.1:8000/places/default/view/Afghanistan-1>{'name': [u'Afghanistan'], 'population': [u'29121286']}2017-01-30 13:09:53 [scrapy.core.engine] DEBUG: Crawled (200) <GET http://127.0.0.1:8000/places/default/index/1> (referer: http://127.0.0.1:8000/places/)2017-01-30 13:09:53 [scrapy.dupefilters] DEBUG: Filtered duplicate request: <GET http://127.0.0.1:8000/places/default/index/1> - no more duplicates will be shown (see DUPEFILTER_DEBUG to show all duplicates)2017-01-30 13:09:53 [scrapy.core.engine] DEBUG: Crawled (200) <GET http://127.0.0.1:8000/places/default/view/Antigua-and-Barbuda-10> (referer: http://127.0.0.1:8000/places/)2017-01-30 13:09:54 [scrapy.core.scraper] DEBUG: Scraped from <200 http://127.0.0.1:8000/places/default/view/Antigua-and-Barbuda-10>{'name': [u'Antigua and Barbuda'], 'population': [u'86754']}2017-01-30 13:09:54 [scrapy.core.engine] DEBUG: Crawled (200) <GET http://127.0.0.1:8000/places/default/view/Antarctica-9> (referer: http://127.0.0.1:8000/places/)2017-01-30 13:09:54 [scrapy.core.scraper] DEBUG: Scraped from <200 http://127.0.0.1:8000/places/default/view/Antarctica-9>{'name': [u'Antarctica'], 'population': [u'0']}... ...wu_being@ubuntukylin64:~/GitHub/WebScrapingWithPython/8.Scrapy爬虫框架/example_wu$ scrapy crawl country -s LOG_LEVEL=INFO --output=countries.csv...2017-01-30 13:11:33 [scrapy.extensions.feedexport] INFO: Stored csv feed (252 items) in: countries.csv2017-01-30 13:11:33 [scrapy.statscollectors] INFO: Dumping Scrapy stats:{'downloader/request_bytes': 160417, 'downloader/request_count': 280, 'downloader/request_method_count/GET': 280, 'downloader/response_bytes': 2844451, 'downloader/response_count': 280, 'downloader/response_status_count/200': 279, 'downloader/response_status_count/400': 1, 'dupefilter/filtered': 61, 'finish_reason': 'finished', 'finish_time': datetime.datetime(2017, 1, 30, 5, 11, 33, 487258), 'item_scraped_count': 252, 'log_count/INFO': 8, 'request_depth_max': 26, 'response_received_count': 280, 'scheduler/dequeued': 279, 'scheduler/dequeued/memory': 279, 'scheduler/enqueued': 279, 'scheduler/enqueued/memory': 279, 'start_time': datetime.datetime(2017, 1, 30, 5, 10, 34, 304933)}2017-01-30 13:11:33 [scrapy.core.engine] INFO: Spider closed (finished)wu_being@ubuntukylin64:~/GitHub/WebScrapingWithPython/8.Scrapy爬虫框架/example_wu$ ...

提取过程最后还输出一些统计信息。我们查看输出文件countries.csv的信息，结果和预期一样。

name,populationAndorra,84000American Samoa,57881Algeria,34586184Albania,2986952Aland Islands,26711Afghanistan,29121286Antigua and Barbuda,86754Antarctica,0Anguilla,13254... ...

2.7中断和恢复爬虫

我们只需要定义用于保存爬虫当前状态目录的JOBDIR设置即可。

wu_being@ubuntukylin64:~/GitHub/WebScrapingWithPython/8.Scrapy爬虫框架/example_wu$ scrapy crawl country -s LOG_LEVEL=DEBUG -s JOBDIR=2.7crawls/country...^C2017-01-30 13:31:27 [scrapy.crawler] INFO: Received SIGINT, shutting down gracefully. Send again to force 2017-01-30 13:33:13 [scrapy.core.scraper] DEBUG: Scraped from <200 http://127.0.0.1:8000/places/default/view/Albania-3>{'name': [u'Albania'], 'population': [u'2986952']}2017-01-30 13:33:15 [scrapy.core.engine] DEBUG: Crawled (200) <GET http://127.0.0.1:8000/places/default/view/Aland-Islands-2> (referer: http://127.0.0.1:8000/places/)2017-01-30 13:33:16 [scrapy.core.scraper] DEBUG: Scraped from <200 http://127.0.0.1:8000/places/default/view/Aland-Islands-2>{'name': [u'Aland Islands'], 'population': [u'26711']}...

我们通过按Ctrl+C发送终止信号，然后等待爬虫再下载几个条目后自动终止，注意不能再按一次Ctrl+C强行终止，否则爬虫保存状态不成功。
我们运行同样的命令恢复爬虫运行。

wu_being@ubuntukylin64:~/GitHub/WebScrapingWithPython/8.Scrapy爬虫框架/example_wu $wu_being@ubuntukylin64:~/GitHub/WebScrapingWithPython/8.Scrapy爬虫框架/example_wu$ scrapy crawl country -s LOG_LEVEL=DEBUG -s JOBDIR=2.7crawls/country...2017-01-30 13:33:21 [scrapy.core.engine] DEBUG: Crawled (400) <GET http://127.0.0.1:8000/robots.txt> (referer: None)2017-01-30 13:33:23 [scrapy.core.engine] DEBUG: Crawled (200) <GET http://127.0.0.1:8000/places/default/view/Barbados-20> (referer: http://127.0.0.1:8000/places/default/index/1)2017-01-30 13:33:23 [scrapy.core.scraper] DEBUG: Scraped from <200 http://127.0.0.1:8000/places/default/view/Barbados-20>{'name': [u'Barbados'], 'population': [u'285653']}2017-01-30 13:33:25 [scrapy.core.engine] DEBUG: Crawled (200) <GET http://127.0.0.1:8000/places/default/view/Bangladesh-19> (referer: http://127.0.0.1:8000/places/default/index/1)2017-01-30 13:33:25 [scrapy.core.scraper] DEBUG: Scraped from <200 http://127.0.0.1:8000/places/default/view/Bangladesh-19>{'name': [u'Bangladesh'], 'population': [u'156118464']}...^C2017-01-30 13:33:43 [scrapy.crawler] INFO: Received SIGINT, shutting down gracefully. Send again to force 2017-01-30 13:33:43 [scrapy.core.engine] INFO: Closing spider (shutdown)^C2017-01-30 13:33:44 [scrapy.crawler] INFO: Received SIGINT twice, forcing unclean shutdownwu_being@ubuntukylin64:~/GitHub/WebScrapingWithPython/8.Scrapy爬虫框架/example_wu$ 

恢复时注意cookie过期问题。文档：http://doc.scrapy.org/en/latest/topics/jobs.html

3.使用Portia编写可视化爬虫

Portia是一款基于scrapy开发的开源工具，该工具可以通过点击要提取的网页部分来创建爬虫，这样就比手式创建CSS选择器的方式更加方便。文档：https://github.com/scrapinghub/portia#running-portia

3.1安装

先使用virtualenv创建一个虚拟python环境，环境名为portia_examle。
pip install virtualenv

wu_being@ubuntukylin64:~/GitHub/WebScrapingWithPython$ virtualenv portia_examle --no-site-packagesNew python executable in /home/wu_being/GitHub/WebScrapingWithPython/portia_examle/bin/pythonInstalling setuptools, pip, wheel...done.wu_being@ubuntukylin64:~/GitHub/WebScrapingWithPython$ source portia_examle/bin/activate(portia_examle) wu_being@ubuntukylin64:~/GitHub/WebScrapingWithPython$ (portia_examle) wu_being@ubuntukylin64:~/GitHub/WebScrapingWithPython$ cd portia_examle/(portia_examle) wu_being@ubuntukylin64:~/GitHub/WebScrapingWithPython/portia_examle$ 

在virtualenv中安装Portia及依赖。

(portia_examle) wu_being@ubuntukylin64:~/GitHub/WebScrapingWithPython/portia_examle$ git clone https://github.com/scrapinghub/portiacd portiapip install -r requirements.txtpip install -e ./slybotcd slydtwistd -n slyd

如果安装成功，在浏览器中访问到Portia工具http://localhost:9001/static/main.html

3.2标注

• Portia启动项，有一个用于输入提取网页URL的文本框，输入http://127.0.0.1:8000/places/ 。默认情况下，项目名被设为new_project，而爬虫名被设为待爬取域名127.0.0.1:8000/places/，这两项都通过单击相应标签进行修改。
• 单击Annotate this page按钮，然后单击国家人口数量。
• 单击+field按钮创建一个名为population的新域，然后单击Done保存。其他的域也是相同操作。
• 完成标注后，单击顶部的蓝色按钮Continue Browsing。

3.3优化爬虫

标注完成后，Portia会生成一个scrapy项目，并将产生的文件保存到data/projects目录中，要运行爬虫，只需执行portiacrawl命令，并带上项目名和爬虫名。

(portia_examle) wu_being@ubuntukylin64:~/GitHub/WebScrapingWithPython/portia_examle$ portiacrawl portia/slyd/data/projects/new_project 如果爬虫默认设置运行太快就遇到服务器错误portiacrawl portia/slyd/data/projects/new_project 127.0.0.1:8000/places/ -s DOWNLOAD_DELAY = 2 -s CONCURRENT_REQUESTS_PER_DOMAIN = 1

配置右边栏面板中的Crawling选项卡中，可以添加/index/和/view/为爬虫跟踪模式，将/user/为排除模式，并勾选Overlay blocked links复选框。

3.4检查结果

(portia_examle) wu_being@ubuntukylin64:~/GitHub/WebScrapingWithPython/portia_examle$ portiacrawl portia/slyd/data/projects/new_project 127.0.0.1:8000/places/ --output=countries.csv -s DOWNLOAD_DELAY = 2 -s CONCURRENT_REQUESTS_PER_DOMAIN = 1

Portia是一个非常方便的与Scrapy配合的工具。对于简单的网站，使用Portia开发爬虫通常速度更快。而对于复杂的网站（比如依赖JavaScript的界面），则可以选择使用Python直接开发Scrapy爬虫。

4.使用Scrapely实现自动化提取

Portia使用了Scrapely库来训练数据建立从网页中提取哪些内容的模型，并在相同结构的其他网页应用该模型。
https://github.com/scrapy/scrapely

(portia_examle) wu_being@ubuntukylin64:~/GitHub/WebScrapingWithPython/portia_examle$ pythonPython 2.7.12 (default, Nov 19 2016, 06:48:10) [GCC 5.4.0 20160609] on linux2Type "help", "copyright", "credits" or "license" for more information.>>> from scrapely import Scraper>>> s=Scraper()>>> train_url='http://127.0.0.1:8000/places/default/view/47'>>> s.train(train_url,{'name':'China','population':'1330044000'})>>> test_url='http://127.0.0.1:8000/places/default/view/239'>>> s.scrape(test_url)[{u'name':[u'United Kingdom'],u'population':[u'62,348,447']}]

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【Python爬虫系列】《【Python爬虫8】Scrapy 爬虫框架》http://blog.csdn.net/u014134180/article/details/55508259
Python爬虫系列的GitHub代码文件：https://github.com/1040003585/WebScrapingWithPython

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