--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/app/django/contrib/gis/feeds.py Tue Oct 14 16:00:59 2008 +0000
@@ -0,0 +1,135 @@
+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)}