from nntplib import NNTP, decode_header
from urllib.request import urlopen
import textwrap
import re
class NewsAgent:
"""
An object that can distribute news items from news sources to news
destinations.
"""
def __init__(self):
self.sources = []
self.destinations = []
def add_source(self, source):
self.sources.append(source)
def addDestination(self, dest):
self.destinations.append(dest)
def distribute(self):
"""
Retrieve all news items from all sources, and Distribute them to all
destinations.
"""
items = []
for source in self.sources:
items.extend(source.get_items())
for dest in self.destinations:
dest.receive_items(items)
class NewsItem:
"""
A simple news item consisting of a title and body text.
"""
def __init__(self, title, body):
self.title = title
self.body = body
class NNTPSource:
"""
A news source that retrieves news items from an NNTP group.
"""
def __init__(self, servername, group, howmany):
self.servername = servername
self.group = group
self.howmany = howmany
def get_items(self):
server = NNTP(self.servername)
resp, count, first, last, name = server.group(self.group)
start = last - self.howmany + 1
resp, overviews = server.over((start, last))
for id, over in overviews:
title = decode_header(over['subject'])
resp, info = server.body(id)
body = '\n'.join(line.decode('latin')
for line in info.lines) + '\n\n'
yield NewsItem(title, body)
server.quit()
class SimpleWebSource:
"""
A news source that extracts news items from a web page using regular
expressions.
"""
def __init__(self, url, title_pattern, body_pattern, encoding='utf8'):
self.url = url
self.title_pattern = re.compile(title_pattern)
self.body_pattern = re.compile(body_pattern)
self.encoding = encoding
def get_items(self):
text = urlopen(self.url).read().decode(self.encoding)
titles = self.title_pattern.findall(text)
bodies = self.body_pattern.findall(text)
for title, body in zip(titles, bodies):
yield NewsItem(title, textwrap.fill(body) + '\n')
class PlainDestination:
"""
A news destination that formats all its news items as plain text.
"""
def receive_items(self, items):
for item in items:
print(item.title)
print('-' * len(item.title))
print(item.body)
class HTMLDestination:
"""
A news destination that formats all its news items as HTML.
"""
def __init__(self, filename):
self.filename = filename
def receive_items(self, items):
out = open(self.filename, 'w')
print("""
Today's News
Today's News
""", file=out)
print('', file=out)
id = 0
for item in items:
id += 1
print(' - {}
'
.format(id, item.title), file=out)
print('
', file=out)
id = 0
for item in items:
id += 1
print(''
.format(id, item.title), file=out)
print('{}'.format(item.body), file=out)
print("""
""", file=out)
def runDefaultSetup():
"""
A default setup of sources and destination. Modify to taste.
"""
agent = NewsAgent()
# A SimpleWebSource that retrieves news from Reuters:
reuters_url = 'http://www.reuters.com/news/world'
reuters_title = r'(.*?)'
reuters_body = r'
(.*?)
'
reuters = SimpleWebSource(reuters_url, reuters_title, reuters_body)
agent.add_source(reuters)
# An NNTPSource that retrieves news from comp.lang.python.announce:
clpa_server = 'news.foo.bar' # Insert real server name
clpa_server = 'news.ntnu.no'
clpa_group = 'comp.lang.python.announce'
clpa_howmany = 10
clpa = NNTPSource(clpa_server, clpa_group, clpa_howmany)
agent.add_source(clpa)
# Add plain-text destination and an HTML destination:
agent.addDestination(PlainDestination())
agent.addDestination(HTMLDestination('news.html'))
# Distribute the news items:
agent.distribute()
if __name__ == '__main__': runDefaultSetup()