mygpo/api/opml.py

   1 # -*- coding: utf-8 -*-
   2
   3 """OPML importer and exporter (based on gPodder's "opml" module)
   4
   5 This module contains helper classes to import subscriptions from OPML files on
   6 the web and to export a list of podcast objects to valid OPML 2.0 files.
   7 """
   8
   9 import os
  10
  11 import xml.dom.minidom
  12 from xml.parsers.expat import ExpatError
  13 import email.utils
  14
  15
  16 class Importer(object):
  17     VALID_TYPES = ("rss", "link")
  18
  19     def __init__(self, content):
  20         """
  21         Parses the OPML feed from the given URL into a local data structure
  22         containing podcast metadata.
  23         """
  24         self.items = []
  25
  26         try:
  27             doc = xml.dom.minidom.parseString(content)
  28         except ExpatError as e:
  29             raise ValueError from e
  30
  31         for outline in doc.getElementsByTagName("outline"):
  32             if (
  33                 outline.getAttribute("type") in self.VALID_TYPES
  34                 and outline.getAttribute("xmlUrl")
  35                 or outline.getAttribute("url")
  36             ):
  37                 channel = {
  38                     "url": outline.getAttribute("xmlUrl")
  39                     or outline.getAttribute("url"),
  40                     "title": outline.getAttribute("title")
  41                     or outline.getAttribute("text")
  42                     or outline.getAttribute("xmlUrl")
  43                     or outline.getAttribute("url"),
  44                     "description": outline.getAttribute("text")
  45                     or outline.getAttribute("xmlUrl")
  46                     or outline.getAttribute("url"),
  47                 }
  48
  49                 if channel["description"] == channel["title"]:
  50                     channel["description"] = channel["url"]
  51
  52                 for attr in ("url", "title", "description"):
  53                     channel[attr] = channel[attr].strip()
  54
  55                 self.items.append(channel)
  56
  57
  58 class Exporter(object):
  59     """
  60     Helper class to export a list of channel objects to a local file in OPML
  61     2.0 format. See www.opml.org for the OPML specification.
  62     """
  63
  64     def __init__(self, title="my.gpodder.org Subscriptions"):
  65         self.title = title
  66         self.created = email.utils.formatdate(localtime=True)
  67
  68     def generate(self, channels):
  69         """
  70         Creates a XML document containing metadata for each channel object in
  71         the "channels" parameter, which should be a list of channel objects.
  72
  73         Returns: An OPML document as string
  74         """
  75         doc = xml.dom.minidom.Document()
  76
  77         opml = doc.createElement("opml")
  78         opml.setAttribute("version", "2.0")
  79         doc.appendChild(opml)
  80
  81         def create_node(name, content):
  82             node = doc.createElement(name)
  83             node.appendChild(doc.createTextNode(content))
  84             return node
  85
  86         head = doc.createElement("head")
  87         head.appendChild(create_node("title", self.title or ""))
  88         head.appendChild(create_node("dateCreated", self.created))
  89         opml.appendChild(head)
  90
  91         def create_outline(channel):
  92             from mygpo.subscriptions.models import SubscribedPodcast
  93             from mygpo.podcasts.models import PodcastGroup
  94
  95             outline = doc.createElement("outline")
  96
  97             if isinstance(channel, SubscribedPodcast):
  98                 title = channel.podcast.title
  99                 outline.setAttribute("xmlUrl", channel.ref_url)
 100                 outline.setAttribute("description", channel.podcast.description or "")
 101                 outline.setAttribute("type", "rss")
 102                 outline.setAttribute("htmlUrl", channel.podcast.link or "")
 103             elif isinstance(channel, PodcastGroup):
 104                 title = channel.title
 105                 for subchannel in channel.podcast_set.all():
 106                     outline.appendChild(create_outline(subchannel))
 107             else:
 108                 title = channel.title
 109                 outline.setAttribute("xmlUrl", channel.url)
 110                 outline.setAttribute("description", channel.description or "")
 111                 outline.setAttribute("type", "rss")
 112                 outline.setAttribute("htmlUrl", channel.link or "")
 113
 114             outline.setAttribute("title", title or "")
 115             outline.setAttribute("text", title or "")
 116             return outline
 117
 118         body = doc.createElement("body")
 119         for channel in channels:
 120             body.appendChild(create_outline(channel))
 121         opml.appendChild(body)
 122
 123         return doc.toprettyxml(encoding="utf-8", indent="  ", newl=os.linesep)