python基础教程项目四之新闻聚合

from nntplib import NNTPfrom time import strftime,time,localtimefrom email import message_from_stringfrom urllib import urlopenimport textwrapimport reday = 24*60*60def wrap(string,max=70):    '''    '''    return ''.join(textwrap.wrap(string)) + ''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 = bodyclass 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(''.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.bodyclass HTMLDestination:    def __init__(self,filename):        self.filename = filename    def receiveItems(self,items):        out = open(self.filename,'w')        print &gt;&gt; out,'''                         <title>Today's News</title>                        <h1>Today's News        '''        print &gt;&gt; out, '<ul>'        id = 0        for item in items:            id += 1            print &gt;&gt; out, '<li><a>%s</a></li>' % (id,item.title)        print &gt;&gt; out, '</ul>'        id = 0        for item in items:            id += 1            print &gt;&gt; out, '<h2><a>%s</a></h2>' % (id,item.title)            print &gt;&gt; out, '<pre class="brush:php;toolbar:false">%s