src/gpodder/opml.py

   1 # -*- coding: utf-8 -*-
   2 #
   3 # gPodder - A media aggregator and podcast client
   4 # Copyright (c) 2005-2010 Thomas Perl and the gPodder Team
   5 #
   6 # gPodder is free software; you can redistribute it and/or modify
   7 # it under the terms of the GNU General Public License as published by
   8 # the Free Software Foundation; either version 3 of the License, or
   9 # (at your option) any later version.
  10 #
  11 # gPodder is distributed in the hope that it will be useful,
  12 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 # GNU General Public License for more details.
  15 #
  16 # You should have received a copy of the GNU General Public License
  17 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
  18 #
  19
  20
  21 #
  22 #  opml.py -- OPML import and export functionality
  23 #  Thomas Perl <thp@perli.net>   2007-08-19
  24 #
  25 #  based on: libopmlreader.py (2006-06-13)
  26 #            libopmlwriter.py (2005-12-08)
  27 #
  28
  29 """OPML import and export functionality
  30
  31 This module contains helper classes to import subscriptions
  32 from OPML files on the web and to export a list of channel
  33 objects to valid OPML 1.1 files that can be used to backup
  34 or distribute gPodder's channel subscriptions.
  35 """
  36
  37 from gpodder.liblogger import log
  38
  39 from gpodder import util
  40
  41 import xml.dom.minidom
  42
  43 import urllib
  44 import urllib2
  45 import os.path
  46 import os
  47 import platform
  48 import shutil
  49
  50 from email.Utils import formatdate
  51 import gpodder
  52
  53
  54 class Importer(object):
  55     """
  56     Helper class to import an OPML feed from protocols
  57     supported by urllib2 (e.g. HTTP) and return a GTK
  58     ListStore that can be displayed in the GUI.
  59
  60     This class should support standard OPML feeds and
  61     contains workarounds to support odeo.com feeds.
  62     """
  63
  64     VALID_TYPES = ( 'rss', 'link' )
  65
  66     def __init__( self, url):
  67         """
  68         Parses the OPML feed from the given URL into
  69         a local data structure containing channel metadata.
  70         """
  71         self.items = []
  72         try:
  73             if os.path.exists(url):
  74                 doc = xml.dom.minidom.parse(url)
  75             else:
  76                 doc = xml.dom.minidom.parseString(util.urlopen(url).read())
  77
  78             for outline in doc.getElementsByTagName('outline'):
  79                 if outline.getAttribute('type') in self.VALID_TYPES and outline.getAttribute('xmlUrl') or outline.getAttribute('url'):
  80                     channel = {
  81                         'url': outline.getAttribute('xmlUrl') or outline.getAttribute('url'),
  82                         'title': outline.getAttribute('title') or outline.getAttribute('text') or outline.getAttribute('xmlUrl') or outline.getAttribute('url'),
  83                         'description': outline.getAttribute('text') or outline.getAttribute('xmlUrl') or outline.getAttribute('url'),
  84                     }
  85
  86                     if channel['description'] == channel['title']:
  87                         channel['description'] = channel['url']
  88
  89                     for attr in ( 'url', 'title', 'description' ):
  90                         channel[attr] = channel[attr].strip()
  91
  92                     self.items.append( channel)
  93             if not len(self.items):
  94                 log( 'OPML import finished, but no items found: %s', url, sender = self)
  95         except:
  96             log( 'Cannot import OPML from URL: %s', url, traceback=True, sender = self)
  97
  98
  99
 100 class Exporter(object):
 101     """
 102     Helper class to export a list of channel objects
 103     to a local file in OPML 1.1 format.
 104
 105     See www.opml.org for the OPML specification.
 106     """
 107
 108     FEED_TYPE = 'rss'
 109
 110     def __init__( self, filename):
 111         if filename.endswith( '.opml') or filename.endswith( '.xml'):
 112             self.filename = filename
 113         else:
 114             self.filename = '%s.opml' % ( filename, )
 115
 116     def create_node( self, doc, name, content):
 117         """
 118         Creates a simple XML Element node in a document
 119         with tag name "name" and text content "content",
 120         as in <name>content</name> and returns the element.
 121         """
 122         node = doc.createElement( name)
 123         node.appendChild( doc.createTextNode( content))
 124         return node
 125
 126     def create_outline( self, doc, channel):
 127         """
 128         Creates a OPML outline as XML Element node in a
 129         document for the supplied channel.
 130         """
 131         outline = doc.createElement( 'outline')
 132         outline.setAttribute( 'title', channel.title)
 133         outline.setAttribute( 'text', channel.description)
 134         outline.setAttribute( 'xmlUrl', channel.url)
 135         outline.setAttribute( 'type', self.FEED_TYPE)
 136         return outline
 137
 138     def write( self, channels):
 139         """
 140         Creates a XML document containing metadata for each
 141         channel object in the "channels" parameter, which
 142         should be a list of channel objects.
 143
 144         OPML 2.0 specification: http://www.opml.org/spec2
 145
 146         Returns True on success or False when there was an
 147         error writing the file.
 148         """
 149         doc = xml.dom.minidom.Document()
 150
 151         opml = doc.createElement('opml')
 152         opml.setAttribute('version', '2.0')
 153         doc.appendChild(opml)
 154
 155         head = doc.createElement( 'head')
 156         head.appendChild( self.create_node( doc, 'title', 'gPodder subscriptions'))
 157         head.appendChild( self.create_node( doc, 'dateCreated', formatdate(localtime=True)))
 158         opml.appendChild( head)
 159
 160         body = doc.createElement( 'body')
 161         for channel in channels:
 162             body.appendChild( self.create_outline( doc, channel))
 163         opml.appendChild( body)
 164
 165         try:
 166             data = doc.toprettyxml(encoding='utf-8', indent='    ', newl=os.linesep)
 167             # We want to have at least 512 KiB free disk space after
 168             # saving the opml data, if this is not possible, don't
 169             # try to save the new file, but keep the old one so we
 170             # don't end up with a clobbed, empty opml file.
 171             FREE_DISK_SPACE_AFTER = 1024*512
 172             available = util.get_free_disk_space(os.path.dirname(self.filename))
 173             if available < 2*len(data)+FREE_DISK_SPACE_AFTER and not gpodder.win32:
 174                 # FIXME: get_free_disk_space still unimplemented for win32
 175                 log('Not enough free disk space to save channel list to %s', self.filename, sender = self)
 176                 return False
 177             fp = open(self.filename+'.tmp', 'w')
 178             fp.write(data)
 179             fp.close()
 180             if gpodder.win32:
 181                 # Win32 does not support atomic rename with os.rename
 182                 shutil.move(self.filename+'.tmp', self.filename)
 183             else:
 184                 os.rename(self.filename+'.tmp', self.filename)
 185         except:
 186             log('Could not open file for writing: %s', self.filename, sender=self, traceback=True)
 187             return False
 188
 189         return True
 190