这篇文章给大家分享的是有关python之如何实现新闻聚合的内容。小编觉得挺实用的,因此分享给大家做个参考,一起跟随小编过来看看吧。
先上代码,然后再来逐一分析:
from nntplib import NNTP from time import strftime,time,localtime from email import message_from_string from urllib import urlopen import textwrap import re day = 24*60*60 def wrap(string,max=70): ''' ''' return '\n'.join(textwrap.wrap(string)) + '\n' class NewsAgent: ''' ''' def __init__(self): self.sources = [] self.destinations = [] def addSource(self,source): self.sources.append(source) def addDestination(self,dest): self.destinations.append(dest) def distribute(self): items = [] for source in self.sources: items.extend(source.getItems()) for dest in self.destinations: dest.receiveItems(items) class NewsItem: def __init__(self,title,body): self.title = title self.body = body class NNTPSource: def __init__(self,servername,group,window): self.servername = servername self.group = group self.window = window def getItems(self): start = localtime(time() - self.window*day) date = strftime('%y%m%d',start) hour = strftime('%H%M%S',start) server = NNTP(self.servername) ids = server.newnews(self.group,date,hour)[1] for id in ids: lines = server.article(id)[3] message = message_from_string('\n'.join(lines)) title = message['subject'] body = message.get_payload() if message.is_multipart(): body = body[0] yield NewsItem(title,body) server.quit() class SimpleWebSource: def __init__(self,url,titlePattern,bodyPattern): self.url = url self.titlePattern = re.compile(titlePattern) self.bodyPattern = re.compile(bodyPattern) def getItems(self): text = urlopen(self.url).read() titles = self.titlePattern.findall(text) bodies = self.bodyPattern.findall(text) for title.body in zip(titles,bodies): yield NewsItem(title,wrap(body)) class PlainDestination: def receiveItems(self,items): for item in items: print item.title print '-'*len(item.title) print item.body class HTMLDestination: def __init__(self,filename): self.filename = filename def receiveItems(self,items): out = open(self.filename,'w') print >> out,''' <html> <head> <title>Today's News</title> </head> <body> <h2>Today's News</hi> ''' print >> out, '<ul>' id = 0 for item in items: id += 1 print >> out, '<li><a href="#" rel="external nofollow" >%s</a></li>' % (id,item.title) print >> out, '</ul>' id = 0 for item in items: id += 1 print >> out, '<h3><a name="%i">%s</a></h3>' % (id,item.title) print >> out, '<pre>%s</pre>' % item.body print >> out, ''' </body> </html> ''' def runDefaultSetup(): agent = NewsAgent() bbc_url = 'http://news.bbc.co.uk/text_only.stm' bbc_title = r'(?s)a href="[^" rel="external nofollow" ]*">\s*<b>\s*(.*?)\s*</b>' bbc_body = r'(?s)</a>\s*<br/>\s*(.*?)\s*<' bbc = SimpleWebSource(bbc_url, bbc_title, bbc_body) agent.addSource(bbc) clpa_server = 'news2.neva.ru' clpa_group = 'alt.sex.telephone' clpa_window = 1 clpa = NNTPSource(clpa_server,clpa_group,clpa_window) agent.addSource(clpa) agent.addDestination(PlainDestination()) agent.addDestination(HTMLDestination('news.html')) agent.distribute() if __name__ == '__main__': runDefaultSetup()
这个程序,首先从整体上进行分析,重点部分在于NewsAgent,它的作用是存储新闻来源,存储目标地址,然后在分别调用来源服务器(NNTPSource以及SimpleWebSource)以及写新闻的类(PlainDestination和HTMLDestination)。所以从这里也看的出,NNTPSource是专门用来获取新闻服务器上的信息的,SimpleWebSource是获取一个url上的数据的。而PlainDestination和HTMLDestination的作用很明显,前者是用来输出获取到的内容到终端的,后者是写数据到html文件中的。
有了这些分析,然后在来看主程序中的内容,主程序就是来给NewsAgent添加信息源和输出目的地址的。
这确实是个简单的程序,不过这个程序可是用到了分层了。
感谢各位的阅读!关于“python之如何实现新闻聚合”这篇文章就分享到这里了,希望以上内容可以对大家有一定的帮助,让大家可以学到更多知识,如果觉得文章不错,可以把它分享出去让更多的人看到吧!
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