app/models/relation.rb

   1 class Relation < ActiveRecord::Base
   2   require 'xml/libxml'
   3
   4   set_table_name 'current_relations'
   5
   6   belongs_to :changeset
   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       doc.find('//osm/relation').each do |pt|
  23         return Relation.from_xml_node(pt, create)
  24       end
  25     rescue
  26       return nil
  27     end
  28   end
  29
  30   def self.from_xml_node(pt, create=false)
  31     relation = Relation.new
  32
  33     if !create and pt['id'] != '0'
  34       relation.id = pt['id'].to_i
  35     end
  36
  37     relation.version = pt['version']
  38     relation.changeset_id = pt['changeset']
  39
  40     if create
  41       relation.timestamp = Time.now
  42       relation.visible = true
  43     else
  44       if pt['timestamp']
  45         relation.timestamp = Time.parse(pt['timestamp'])
  46       end
  47     end
  48
  49     pt.find('tag').each do |tag|
  50       relation.add_tag_keyval(tag['k'], tag['v'])
  51     end
  52
  53     pt.find('member').each do |member|
  54       relation.add_member(member['type'], member['ref'], member['role'])
  55     end
  56
  57     return relation
  58   end
  59
  60   def to_xml
  61     doc = OSM::API.new.get_xml_doc
  62     doc.root << to_xml_node()
  63     return doc
  64   end
  65
  66   def to_xml_node(user_display_name_cache = nil)
  67     el1 = XML::Node.new 'relation'
  68     el1['id'] = self.id.to_s
  69     el1['visible'] = self.visible.to_s
  70     el1['timestamp'] = self.timestamp.xmlschema
  71     el1['version'] = self.version.to_s
  72     el1['changeset'] = self.changeset_id.to_s
  73
  74     user_display_name_cache = {} if user_display_name_cache.nil?
  75
  76     if user_display_name_cache and user_display_name_cache.key?(self.changeset.user_id)
  77       # use the cache if available
  78     elsif self.user.data_public?
  79       user_display_name_cache[self.changeset.user_id] = self.changeset.user.display_name
  80     else
  81       user_display_name_cache[self.changeset.user_id] = nil
  82     end
  83
  84     el1['user'] = user_display_name_cache[self.changeset.user_id] unless user_display_name_cache[self.changeset.user_id].nil?
  85
  86     self.relation_members.each do |member|
  87       p=0
  88       #if visible_members
  89       #  # if there is a list of visible members then use that to weed out deleted segments
  90       #  if visible_members[member.member_type][member.member_id]
  91       #    p=1
  92       #  end
  93       #else
  94         # otherwise, manually go to the db to check things
  95         if member.member.visible?
  96           p=1
  97         end
  98       #end
  99       if p
 100         e = XML::Node.new 'member'
 101         e['type'] = member.member_type
 102         e['ref'] = member.member_id.to_s
 103         e['role'] = member.member_role
 104         el1 << e
 105        end
 106     end
 107
 108     self.relation_tags.each do |tag|
 109       e = XML::Node.new 'tag'
 110       e['k'] = tag.k
 111       e['v'] = tag.v
 112       el1 << e
 113     end
 114     return el1
 115   end
 116
 117   def self.find_for_nodes(ids, options = {})
 118     if ids.empty?
 119       return []
 120     else
 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 = 'node' AND current_relation_members.member_id IN (#{ids.join(',')})" }) do
 122         return self.find(:all, options)
 123       end
 124     end
 125   end
 126
 127   def self.find_for_ways(ids, options = {})
 128     if ids.empty?
 129       return []
 130     else
 131       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
 132         return self.find(:all, options)
 133       end
 134     end
 135   end
 136
 137   def self.find_for_relations(ids, options = {})
 138     if ids.empty?
 139       return []
 140     else
 141       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
 142         return self.find(:all, options)
 143       end
 144     end
 145   end
 146
 147   # FIXME is this really needed?
 148   def members
 149     unless @members
 150       @members = Array.new
 151       self.relation_members.each do |member|
 152         @members += [[member.member_type,member.member_id,member.member_role]]
 153       end
 154     end
 155     @members
 156   end
 157
 158   def tags
 159     unless @tags
 160       @tags = Hash.new
 161       self.relation_tags.each do |tag|
 162         @tags[tag.k] = tag.v
 163       end
 164     end
 165     @tags
 166   end
 167
 168   def members=(m)
 169     @members = m
 170   end
 171
 172   def tags=(t)
 173     @tags = t
 174   end
 175
 176   def add_member(type,id,role)
 177     @members = Array.new unless @members
 178     @members += [[type,id,role]]
 179   end
 180
 181   def add_tag_keyval(k, v)
 182     @tags = Hash.new unless @tags
 183     @tags[k] = v
 184   end
 185
 186   def save_with_history!
 187     Relation.transaction do
 188       t = Time.now
 189       self.version += 1
 190       self.timestamp = t
 191       self.save!
 192
 193       tags = self.tags
 194       RelationTag.delete_all(['id = ?', self.id])
 195       tags.each do |k,v|
 196         tag = RelationTag.new
 197         tag.k = k
 198         tag.v = v
 199         tag.id = self.id
 200         tag.save!
 201       end
 202
 203       members = self.members
 204       RelationMember.delete_all(['id = ?', self.id])
 205       members.each do |n|
 206         mem = RelationMember.new
 207         mem.id = self.id
 208         mem.member_type = n[0];
 209         mem.member_id = n[1];
 210         mem.member_role = n[2];
 211         mem.save!
 212       end
 213
 214       old_relation = OldRelation.from_relation(self)
 215       old_relation.timestamp = t
 216       old_relation.save_with_dependencies!
 217     end
 218   end
 219
 220   def delete_with_history(new_relation, user)
 221     if self.visible
 222       check_consistency(self, new_relation, user)
 223       if RelationMember.find(:first, :joins => "INNER JOIN current_relations ON current_relations.id=current_relation_members.id", :conditions => [ "visible = 1 AND member_type='relation' and member_id=?", self.id ])
 224         raise OSM::APIPreconditionFailedError.new
 225       else
 226         #self.user_id = user.id
 227         # FIXME we need to deal with changeset here, which is probably already dealt with
 228         self.changeset_id = new_relation.changeset_id
 229         self.tags = []
 230         self.members = []
 231         self.visible = false
 232         save_with_history!
 233       end
 234     else
 235       raise OSM::APIAlreadyDeletedError.new
 236     end
 237   end
 238
 239   def update_from(new_relation, user)
 240     check_consistency(self, new_relation, user)
 241     if !new_relation.preconditions_ok?
 242       raise OSM::APIPreconditionFailedError.new
 243     end
 244     # FIXME need to deal with changeset etc
 245     #self.user_id = user.id
 246     self.changeset_id = new_relation.changeset_id
 247     self.tags = new_relation.tags
 248     self.members = new_relation.members
 249     self.visible = true
 250     save_with_history!
 251   end
 252
 253   def preconditions_ok?
 254     # These are hastables that store an id in the index of all
 255     # the nodes/way/relations that have already been added.
 256     # Once we know the id of the node/way/relation exists
 257     # we check to see if it is already existing in the hashtable
 258     # if it does, then we return false. Otherwise
 259     # we add it to the relevant hash table, with the value true..
 260     # Thus if you have nodes with the ids of 50 and 1 already in the
 261     # relation, then the hash table nodes would contain:
 262     # => {50=>true, 1=>true}
 263     nodes = Hash.new
 264     ways = Hash.new
 265     relations = Hash.new
 266     self.members.each do |m|
 267       if (m[0] == "node")
 268         n = Node.find(:first, :conditions => ["id = ?", m[1]])
 269         unless n and n.visible
 270           return false
 271         end
 272         if nodes[m[1]]
 273           return false
 274         else
 275           nodes[m[1]] = true
 276         end
 277       elsif (m[0] == "way")
 278         w = Way.find(:first, :conditions => ["id = ?", m[1]])
 279         unless w and w.visible and w.preconditions_ok?
 280           return false
 281         end
 282         if ways[m[1]]
 283           return false
 284         else
 285           ways[m[1]] = true
 286         end
 287       elsif (m[0] == "relation")
 288         e = Relation.find(:first, :conditions => ["id = ?", m[1]])
 289         unless e and e.visible and e.preconditions_ok?
 290           return false
 291         end
 292         if relations[m[1]]
 293           return false
 294         else
 295           relations[m[1]] = true
 296         end
 297       else
 298         return false
 299       end
 300     end
 301     return true
 302   rescue
 303     return false
 304   end
 305
 306   # Temporary method to match interface to nodes
 307   def tags_as_hash
 308     return self.tags
 309   end
 310 end