+
−from django.contrib.syndication.feeds import Feed as BaseFeed, FeedDoesNotExist
+
−from django.utils.feedgenerator import Atom1Feed, Rss201rev2Feed
+
−
+
−class GeoFeedMixin(object):
+
−    """
+
−    This mixin provides the necessary routines for SyndicationFeed subclasses
+
−    to produce simple GeoRSS or W3C Geo elements.
+
−    """
+
−
+
−    def georss_coords(self, coords):
+
−        """
+
−        In GeoRSS coordinate pairs are ordered by lat/lon and separated by
+
−        a single white space.  Given a tuple of coordinates, this will return
+
−        a unicode GeoRSS representation.
+
−        """
+
−        return u' '.join([u'%f %f' % (coord[1], coord[0]) for coord in coords])
+
−
+
−    def add_georss_point(self, handler, coords, w3c_geo=False):
+
−        """
+
−        Adds a GeoRSS point with the given coords using the given handler.
+
−        Handles the differences between simple GeoRSS and the more pouplar
+
−        W3C Geo specification.
+
−        """
+
−        if w3c_geo:
+
−            lon, lat = coords[:2]
+
−            handler.addQuickElement(u'geo:lat', u'%f' % lat)
+
−            handler.addQuickElement(u'geo:lon', u'%f' % lon)
+
−        else:
+
−            handler.addQuickElement(u'georss:point', self.georss_coords((coords,)))
+
−
+
−    def add_georss_element(self, handler, item, w3c_geo=False):
+
−        """
+
−        This routine adds a GeoRSS XML element using the given item and handler.
+
−        """
+
−        # Getting the Geometry object.
+
−        geom = item.get('geometry', None)
+
−        if not geom is None:
+
−            if isinstance(geom, (list, tuple)):
+
−                # Special case if a tuple/list was passed in.  The tuple may be
+
−                # a point or a box
+
−                box_coords = None
+
−                if isinstance(geom[0], (list, tuple)):
+
−                    # Box: ( (X0, Y0), (X1, Y1) )
+
−                    if len(geom) == 2:
+
−                        box_coords = geom
+
−                    else:
+
−                        raise ValueError('Only should be two sets of coordinates.')
+
−                else:
+
−                    if len(geom) == 2:
+
−                        # Point: (X, Y)
+
−                        self.add_georss_point(handler, geom, w3c_geo=w3c_geo)
+
−                    elif len(geom) == 4:
+
−                        # Box: (X0, Y0, X1, Y1)
+
−                        box_coords = (geom[:2], geom[2:])
+
−                    else:
+
−                        raise ValueError('Only should be 2 or 4 numeric elements.')
+
−                # If a GeoRSS box was given via tuple.
+
−                if not box_coords is None:
+
−                    if w3c_geo: raise ValueError('Cannot use simple GeoRSS box in W3C Geo feeds.')
+
−                    handler.addQuickElement(u'georss:box', self.georss_coords(box_coords))
+
−            else:
+
−                # Getting the lower-case geometry type.
+
−                gtype = str(geom.geom_type).lower()
+
−                if gtype == 'point':
+
−                    self.add_georss_point(handler, geom.coords, w3c_geo=w3c_geo) 
+
−                else:
+
−                    if w3c_geo: raise ValueError('W3C Geo only supports Point geometries.')
+
−                    # For formatting consistent w/the GeoRSS simple standard:
+
−                    # http://georss.org/1.0#simple
+
−                    if gtype in ('linestring', 'linearring'):
+
−                        handler.addQuickElement(u'georss:line', self.georss_coords(geom.coords))
+
−                    elif gtype in ('polygon',):
+
−                        # Only support the exterior ring.
+
−                        handler.addQuickElement(u'georss:polygon', self.georss_coords(geom[0].coords))
+
−                    else:
+
−                        raise ValueError('Geometry type "%s" not supported.' % geom.geom_type)
+
−
+
−### SyndicationFeed subclasses ###
+
−class GeoRSSFeed(Rss201rev2Feed, GeoFeedMixin):
+
−    def rss_attributes(self):
+
−        attrs = super(GeoRSSFeed, self).rss_attributes()
+
−        attrs[u'xmlns:georss'] = u'http://www.georss.org/georss'
+
−        return attrs
+
−
+
−    def add_item_elements(self, handler, item):
+
−        super(GeoRSSFeed, self).add_item_elements(handler, item)
+
−        self.add_georss_element(handler, item)
+
−
+
−    def add_root_elements(self, handler):
+
−        super(GeoRSSFeed, self).add_root_elements(handler)
+
−        self.add_georss_element(handler, self.feed)
+
−
+
−class GeoAtom1Feed(Atom1Feed, GeoFeedMixin):
+
−    def root_attributes(self):
+
−        attrs = super(GeoAtom1Feed, self).root_attributes()
+
−        attrs[u'xmlns:georss'] = u'http://www.georss.org/georss'
+
−        return attrs
+
−
+
−    def add_item_elements(self, handler, item):
+
−        super(GeoAtom1Feed, self).add_item_elements(handler, item)
+
−        self.add_georss_element(handler, item)
+
−
+
−    def add_root_elements(self, handler):
+
−        super(GeoAtom1Feed, self).add_root_elements(handler)
+
−        self.add_georss_element(handler, self.feed)
+
−
+
−class W3CGeoFeed(Rss201rev2Feed, GeoFeedMixin):
+
−    def rss_attributes(self):
+
−        attrs = super(W3CGeoFeed, self).rss_attributes()
+
−        attrs[u'xmlns:geo'] = u'http://www.w3.org/2003/01/geo/wgs84_pos#'
+
−        return attrs
+
−
+
−    def add_item_elements(self, handler, item):
+
−        super(W3CGeoFeed, self).add_item_elements(handler, item)
+
−        self.add_georss_element(handler, item, w3c_geo=True)
+
−
+
−    def add_root_elements(self, handler):
+
−        super(W3CGeoFeed, self).add_root_elements(handler)
+
−        self.add_georss_element(handler, self.feed, w3c_geo=True)
+
−
+
−### Feed subclass ###
+
−class Feed(BaseFeed):
+
−    """
+
−    This is a subclass of the `Feed` from `django.contrib.syndication`.
+
−    This allows users to define a `geometry(obj)` and/or `item_geometry(item)`
+
−    methods on their own subclasses so that geo-referenced information may
+
−    placed in the feed.
+
−    """
+
−    feed_type = GeoRSSFeed
+
−
+
−    def feed_extra_kwargs(self, obj):
+
−        return {'geometry' : self.__get_dynamic_attr('geometry', obj)}
+
−
+
−    def item_extra_kwargs(self, item):
+
−        return {'geometry' : self.__get_dynamic_attr('item_geometry', item)}