+ # - [0] in case some thing links to node 0 which doesn't exist. Shouldn't actually ever happen but it does. FIXME: file a ticket for this
+ nodes_to_fetch = (list_of_way_nodes.uniq - node_ids) - [0]
+
+ if nodes_to_fetch.length > 0
+ @nodes += Node.includes(:node_tags).find(nodes_to_fetch)
+ end
+
+ visible_nodes = {}
+ changeset_cache = {}
+ user_display_name_cache = {}
+
+ @nodes.each do |node|
+ if node.visible?
+ doc.root << node.to_xml_node(changeset_cache, user_display_name_cache)
+ visible_nodes[node.id] = node
+ end
+ end
+
+ way_ids = Array.new
+ ways.each do |way|
+ if way.visible?
+ doc.root << way.to_xml_node(visible_nodes, changeset_cache, user_display_name_cache)
+ way_ids << way.id
+ end
+ end
+
+ relations = Relation.nodes(visible_nodes.keys).visible +
+ Relation.ways(way_ids).visible
+
+ # we do not normally return the "other" partners referenced by an relation,
+ # e.g. if we return a way A that is referenced by relation X, and there's
+ # another way B also referenced, that is not returned. But we do make
+ # an exception for cases where an relation references another *relation*;
+ # in that case we return that as well (but we don't go recursive here)
+ relations += Relation.relations(relations.collect { |r| r.id }).visible
+
+ # this "uniq" may be slightly inefficient; it may be better to first collect and output
+ # all node-related relations, then find the *not yet covered* way-related ones etc.
+ relations.uniq.each do |relation|
+ doc.root << relation.to_xml_node(nil, changeset_cache, user_display_name_cache)
+ end
+
+ response.headers["Content-Disposition"] = "attachment; filename=\"map.osm\""
+
+ render :text => doc.to_s, :content_type => "text/xml"
+ end
+
+ # Get a list of the tiles that have changed within a specified time
+ # period
+ def changes
+ zoom = (params[:zoom] || '12').to_i
+
+ if params.include?(:start) and params.include?(:end)
+ starttime = Time.parse(params[:start])
+ endtime = Time.parse(params[:end])
+ else
+ hours = (params[:hours] || '1').to_i.hours
+ endtime = Time.now.getutc
+ starttime = endtime - hours
+ end
+
+ if zoom >= 1 and zoom <= 16 and
+ endtime > starttime and endtime - starttime <= 24.hours
+ mask = (1 << zoom) - 1
+
+ tiles = Node.where(:timestamp => starttime .. endtime).group("maptile_for_point(latitude, longitude, #{zoom})").count
+
+ doc = OSM::API.new.get_xml_doc
+ changes = XML::Node.new 'changes'
+ changes["starttime"] = starttime.xmlschema
+ changes["endtime"] = endtime.xmlschema
+
+ tiles.each do |tile, count|
+ x = (tile.to_i >> zoom) & mask
+ y = tile.to_i & mask
+
+ t = XML::Node.new 'tile'
+ t["x"] = x.to_s
+ t["y"] = y.to_s
+ t["z"] = zoom.to_s
+ t["changes"] = count.to_s
+
+ changes << t
+ end
+
+ doc.root << changes
+
+ render :text => doc.to_s, :content_type => "text/xml"
+ else
+ render :text => "Requested zoom is invalid, or the supplied start is after the end time, or the start duration is more than 24 hours", :status => :bad_request
+ end
+ end
+
+ # External apps that use the api are able to query the api to find out some
+ # parameters of the API. It currently returns:
+ # * minimum and maximum API versions that can be used.
+ # * maximum area that can be requested in a bbox request in square degrees
+ # * number of tracepoints that are returned in each tracepoints page
+ def capabilities
+ doc = OSM::API.new.get_xml_doc
+
+ api = XML::Node.new 'api'
+ version = XML::Node.new 'version'
+ version['minimum'] = "#{API_VERSION}";
+ version['maximum'] = "#{API_VERSION}";
+ api << version
+ area = XML::Node.new 'area'
+ area['maximum'] = MAX_REQUEST_AREA.to_s;
+ api << area
+ tracepoints = XML::Node.new 'tracepoints'
+ tracepoints['per_page'] = TRACEPOINTS_PER_PAGE.to_s
+ api << tracepoints
+ waynodes = XML::Node.new 'waynodes'
+ waynodes['maximum'] = MAX_NUMBER_OF_WAY_NODES.to_s
+ api << waynodes
+ changesets = XML::Node.new 'changesets'
+ changesets['maximum_elements'] = Changeset::MAX_ELEMENTS.to_s
+ api << changesets
+ timeout = XML::Node.new 'timeout'
+ timeout['seconds'] = API_TIMEOUT.to_s
+ api << timeout