root/branches/gajim_0.11.1/src/common/atom.py

# -*- coding: utf-8 -*-
''' Atom (rfc 4287) feed parser, used to read data from atom-over-pubsub transports
and services. Very simple. Actually implements only atom:entry. Implement more features
if you need. '''

# suggestion: rewrite functions that return dates to return standard python time tuples,
# exteneded to contain timezone

import xmpp
import time

class PersonConstruct(xmpp.Node, object):
        ''' Not used for now, as we don't need authors/contributors in pubsub.com feeds.
        They rarely exist there. '''
        def __init__(self, node):
                ''' Create person construct from node. '''
                xmpp.Node.__init__(self, node=node)

        def get_name(self):
                return self.getTagData('name')

        name = property(get_name, None, None,
                '''Conveys a human-readable name for the person. Should not be None,
                although some badly generated atom feeds don't put anything here
                (this is non-standard behavior, still pubsub.com sometimes does that.)''')

        def get_uri(self):
                return self.getTagData('uri')

        uri = property(get_uri, None, None,
                '''Conveys an IRI associated with the person. Might be None when not set.''')

        def get_email(self):
                return self.getTagData('email')

        email = property(get_email, None, None,
                '''Conveys an e-mail address associated with the person. Might be None when
                not set.''')

class Entry(xmpp.Node, object):
        def __init__(self, node=None):
                ''' Create new atom entry object. '''
                xmpp.Node.__init__(self, 'entry', node=node)

        def __repr__(self):
                return '<Atom:Entry object of id="%r">' % self.id

class OldEntry(xmpp.Node, object):
        ''' Parser for feeds from pubsub.com. They use old Atom 0.3 format with
        their extensions. '''
        def __init__(self, node=None):
                ''' Create new Atom 0.3 entry object. '''
                xmpp.Node.__init__(self, 'entry', node=node)

        def __repr__(self):
                return '<Atom0.3:Entry object of id="%r">' % self.id

        def get_feed_title(self):
                ''' Returns title of feed, where the entry was created. The result is the feed name
                concatenated with source-feed title. '''
                if self.parent is not None:
                        main_feed = self.parent.getTagData('title')
                else:
                        main_feed = None

                if self.getTag('source-feed') is not None:
                        source_feed = self.getTag('source-feed').getTagData('title')
                else:
                        source_feed = None

                if main_feed is not None and source_feed is not None:
                        return u'%s: %s' % (main_feed, source_feed)
                elif main_feed is not None:
                        return main_feed
                elif source_feed is not None:
                        return source_feed
                else:
                        return u''

        feed_title = property(get_feed_title, None, None, 
                ''' Title of feed. It is built from entry's original feed title and title of feed
                which delivered this entry. ''')

        def get_feed_link(self):
                ''' Get a link to main page of feed (in pubsub.com: second link of rel='alternate',
                first contains raw xml data). '''
                try:
                        return self.getTag('source-feed').getTags('link', {'rel':'alternate'})[1].getData()
                except:
                        return None

        feed_link = property(get_feed_link, None, None,
                ''' Link to main webpage of the feed. ''')

        def get_title(self):
                ''' Get an entry's title. '''
                return self.getTagData('title')

        title = property(get_title, None, None,
                ''' Entry's title. ''')

        def get_uri(self):
                ''' Get the uri the entry points to (entry's first link element with rel='alternate'
                or without rel attribute). '''
                for element in self.getTags('link'):
                        if element.attrs.has_key('rel') and element.attrs['rel']<>'alternate': continue
                        try:
                                return element.attrs['href']
                        except AttributeError:
                                pass
                return None

        uri = property(get_uri, None, None,
                ''' URI that is pointed by the entry. ''')

        def get_updated(self):
                ''' Get the time the entry was updated last time. This should be standarized,
                but pubsub.com sends it in human-readable format. We won't try to parse it.
                (Atom 0.3 uses the word «modified» for that).

                If there's no time given in the entry, we try with <published>
                and <issued> elements. '''
                for name in ('updated', 'modified', 'published', 'issued'):
                        date = self.getTagData(name)
                        if date is not None: break

                if date is None:
                        # it is not in the standard format
                        return time.asctime()

                return date

        updated = property(get_updated, None, None, 
                ''' Last significant modification time. ''')

        feed_tagline = u''