- begin
- relation = Relation.find(params[:id])
-
- if relation.visible
-
- # first find the ids of nodes, ways and relations referenced by this
- # relation - note that we exclude this relation just in case.
-
- node_ids = relation.members.select { |m| m[0] == 'Node' }.map { |m| m[1] }
- way_ids = relation.members.select { |m| m[0] == 'Way' }.map { |m| m[1] }
- relation_ids = relation.members.select { |m| m[0] == 'Relation' and m[1] != relation.id }.map { |m| m[1] }
-
- # next load the relations and the ways.
-
- relations = Relation.find(relation_ids, :include => [:relation_tags])
- ways = Way.find(way_ids, :include => [:way_nodes, :way_tags])
-
- # now additionally collect nodes referenced by ways. Note how we
- # recursively evaluate ways but NOT relations.
-
- way_node_ids = ways.collect { |way|
- way.way_nodes.collect { |way_node| way_node.node_id }
- }
- node_ids += way_node_ids.flatten
- nodes = Node.find(node_ids.uniq, :include => :node_tags)
-
- # create XML.
- doc = OSM::API.new.get_xml_doc
- visible_nodes = {}
- visible_members = { "Node" => [], "Way" => [], "Relation" => [] }
- changeset_cache = {}
- user_display_name_cache = {}
-
- nodes.each do |node|
- if node.visible? # should be unnecessary if data is consistent.
- doc.root << node.to_xml_node(changeset_cache, user_display_name_cache)
- visible_nodes[node.id] = node
- visible_members["Node"][node.id] = true
- end
- end
- ways.each do |way|
- if way.visible? # should be unnecessary if data is consistent.
- doc.root << way.to_xml_node(visible_nodes, changeset_cache, user_display_name_cache)
- visible_members["Way"][way.id] = true
- end
- end
- relations.each do |rel|
- if rel.visible? # should be unnecessary if data is consistent.
- doc.root << rel.to_xml_node(nil, changeset_cache, user_display_name_cache)
- visible_members["Relation"][rel.id] = true
- end
- end
- # finally add self and output
- doc.root << relation.to_xml_node(visible_members, changeset_cache, user_display_name_cache)
- render :text => doc.to_s, :content_type => "text/xml"
-
- else
- render :nothing => true, :status => :gone
- end