app/models/relation.rb

   1 class Relation < ActiveRecord::Base
   2   require 'xml/libxml'
   3
   4   set_table_name 'current_relations'
   5
   6   belongs_to :user
   7
   8   has_many :old_relations, :foreign_key => 'id', :order => 'version'
   9
  10   has_many :relation_members, :foreign_key => 'id'
  11   has_many :relation_tags, :foreign_key => 'id'
  12
  13   has_many :containing_relation_members, :class_name => "RelationMember", :as => :member
  14   has_many :containing_relations, :class_name => "Relation", :through => :containing_relation_members, :source => :relation, :extend => ObjectFinder
  15
  16   def self.from_xml(xml, create=false)
  17     begin
  18       p = XML::Parser.new
  19       p.string = xml
  20       doc = p.parse
  21
  22       relation = Relation.new
  23
  24       doc.find('//osm/relation').each do |pt|
  25         if !create and pt['id'] != '0'
  26           relation.id = pt['id'].to_i
  27         end
  28
  29         if create
  30           relation.timestamp = Time.now
  31           relation.visible = true
  32         else
  33           if pt['timestamp']
  34             relation.timestamp = Time.parse(pt['timestamp'])
  35           end
  36         end
  37
  38         pt.find('tag').each do |tag|
  39           relation.add_tag_keyval(tag['k'], tag['v'])
  40         end
  41
  42         pt.find('member').each do |member|
  43           relation.add_member(member['type'], member['ref'], member['role'])
  44         end
  45       end
  46     rescue
  47       relation = nil
  48     end
  49
  50     return relation
  51   end
  52
  53   def to_xml
  54     doc = OSM::API.new.get_xml_doc
  55     doc.root << to_xml_node()
  56     return doc
  57   end
  58
  59   def to_xml_node(user_display_name_cache = nil)
  60     el1 = XML::Node.new 'relation'
  61     el1['id'] = self.id.to_s
  62     el1['visible'] = self.visible.to_s
  63     el1['timestamp'] = self.timestamp.xmlschema
  64
  65     user_display_name_cache = {} if user_display_name_cache.nil?
  66
  67     if user_display_name_cache and user_display_name_cache.key?(self.user_id)
  68       # use the cache if available
  69     elsif self.user.data_public?
  70       user_display_name_cache[self.user_id] = self.user.display_name
  71     else
  72       user_display_name_cache[self.user_id] = nil
  73     end
  74
  75     el1['user'] = user_display_name_cache[self.user_id] unless user_display_name_cache[self.user_id].nil?
  76
  77     self.relation_members.each do |member|
  78       p=0
  79       #if visible_members
  80       #  # if there is a list of visible members then use that to weed out deleted segments
  81       #  if visible_members[member.member_type][member.member_id]
  82       #    p=1
  83       #  end
  84       #else
  85         # otherwise, manually go to the db to check things
  86         if member.member.visible?
  87           p=1
  88         end
  89       #end
  90       if p
  91         e = XML::Node.new 'member'
  92         e['type'] = member.member_type
  93         e['ref'] = member.member_id.to_s
  94         e['role'] = member.member_role
  95         el1 << e
  96        end
  97     end
  98
  99     self.relation_tags.each do |tag|
 100       e = XML::Node.new 'tag'
 101       e['k'] = tag.k
 102       e['v'] = tag.v
 103       el1 << e
 104     end
 105     return el1
 106   end
 107
 108   def self.find_for_nodes(ids, options = {})
 109     self.with_scope(:find => { :joins => "INNER JOIN current_relation_members ON current_relation_members.id = current_relations.id", :conditions => "current_relation_members.member_type = 'node' AND current_relation_members.member_id IN (#{ids.join(',')})" }) do
 110       return self.find(:all, options)
 111     end
 112   end
 113
 114   def self.find_for_ways(ids, options = {})
 115     self.with_scope(:find => { :joins => "INNER JOIN current_relation_members ON current_relation_members.id = current_relations.id", :conditions => "current_relation_members.member_type = 'way' AND current_relation_members.member_id IN (#{ids.join(',')})" }) do
 116       return self.find(:all, options)
 117     end
 118   end
 119
 120   def self.find_for_relations(ids, options = {})
 121     self.with_scope(:find => { :joins => "INNER JOIN current_relation_members ON current_relation_members.id = current_relations.id", :conditions => "current_relation_members.member_type = 'relation' AND current_relation_members.member_id IN (#{ids.join(',')})" }) do
 122       return self.find(:all, options)
 123     end
 124   end
 125
 126   # FIXME is this really needed?
 127   def members
 128     unless @members
 129       @members = Array.new
 130       self.relation_members.each do |member|
 131         @members += [[member.member_type,member.member_id,member.member_role]]
 132       end
 133     end
 134     @members
 135   end
 136
 137   def tags
 138     unless @tags
 139       @tags = Hash.new
 140       self.relation_tags.each do |tag|
 141         @tags[tag.k] = tag.v
 142       end
 143     end
 144     @tags
 145   end
 146
 147   def members=(m)
 148     @members = m
 149   end
 150
 151   def tags=(t)
 152     @tags = t
 153   end
 154
 155   def add_member(type,id,role)
 156     @members = Array.new unless @members
 157     @members += [[type,id,role]]
 158   end
 159
 160   def add_tag_keyval(k, v)
 161     @tags = Hash.new unless @tags
 162     @tags[k] = v
 163   end
 164
 165   def save_with_history!
 166     Relation.transaction do
 167       t = Time.now
 168       self.timestamp = t
 169       self.save!
 170
 171       tags = self.tags
 172
 173       RelationTag.delete_all(['id = ?', self.id])
 174
 175       tags.each do |k,v|
 176         tag = RelationTag.new
 177         tag.k = k
 178         tag.v = v
 179         tag.id = self.id
 180         tag.save!
 181       end
 182
 183       members = self.members
 184
 185       RelationMember.delete_all(['id = ?', self.id])
 186
 187       members.each do |n|
 188         mem = RelationMember.new
 189         mem.id = self.id
 190         mem.member_type = n[0];
 191         mem.member_id = n[1];
 192         mem.member_role = n[2];
 193         mem.save!
 194       end
 195
 196       old_relation = OldRelation.from_relation(self)
 197       old_relation.timestamp = t
 198       old_relation.save_with_dependencies!
 199     end
 200   end
 201
 202   def preconditions_ok?
 203     # These are hastables that store an id in the index of all
 204     # the nodes/way/relations that have already been added.
 205     # Once we know the id of the node/way/relation exists
 206     # we check to see if it is already existing in the hashtable
 207     # if it does, then we return false. Otherwise
 208     # we add it to the relevant hash table, with the value true..
 209     # Thus if you have nodes with the ids of 50 and 1 already in the
 210     # relation, then the hash table nodes would contain:
 211     # => {50=>true, 1=>true}
 212     nodes = Hash.new
 213     ways = Hash.new
 214     relations = Hash.new
 215     self.members.each do |m|
 216       if (m[0] == "node")
 217         n = Node.find(:first, :conditions => ["id = ?", m[1]])
 218         unless n and n.visible
 219           return false
 220         end
 221         if nodes[m[1]]
 222           return false
 223         else
 224           nodes[m[1]] = true
 225         end
 226       elsif (m[0] == "way")
 227         w = Way.find(:first, :conditions => ["id = ?", m[1]])
 228         unless w and w.visible and w.preconditions_ok?
 229           return false
 230         end
 231         if ways[m[1]]
 232           return false
 233         else
 234           ways[m[1]] = true
 235         end
 236       elsif (m[0] == "relation")
 237         e = Relation.find(:first, :conditions => ["id = ?", m[1]])
 238         unless e and e.visible and e.preconditions_ok?
 239           return false
 240         end
 241         if relations[m[1]]
 242           return false
 243         else
 244           relations[m[1]] = true
 245         end
 246       else
 247         return false
 248       end
 249     end
 250     return true
 251   rescue
 252     return false
 253   end
 254
 255   # Temporary method to match interface to nodes
 256   def tags_as_hash
 257     return self.tags
 258   end
 259 end